WJEC Level 3 Diploma in ENVIRONMENTAL SCIENCE€¦ · Level 3 Diploma in Environmental Science 4...

LEVEL 3

WJEC Level 3 Diploma in

ENVIRONMENTALSCIENCE

Teaching from 2015

SPECIMEN ASSESSMENTMATERIALS - External

Level 3 Diploma in Environmental Science 1

Contents

Page Unit 2 Details of assessment 4 Unit 2 Assessment materials 5 Unit 2 Assessment grid 18 Unit 2 Mark bands 19 Unit 4 Details of assessment 26 Unit 4 Administration of pre-release article 26 Unit 4 Pre-release article 27 Unit 4 Question paper 37 Unit 4 Mark scheme 55 Unit 4 Assessment grids 65


Unit 2 Details of assessment

This unit is externally assessed by an assignment which is set and marked by WJEC. The

assessment for the unit will be provided annually by WJEC in September of the academic

year in which it is to be taken via the WJEC secure website. The assessment must be

completed and submitted for marking in the same academic year as it is set. Centres are not

allowed to modify the provided assignment for units 2.


WJEC LEVEL 3 Diploma in Environmental Science /

Extended Diploma in Environmental Science

SPECIMEN ASSESSMENT MATERIALS

Unit 2 The living environment and conservation

Activity one: Investigation

Activity two: Data Analysis


Index

Page Number

Activity 1A/1B: Investigation into how human activity can affect ecosystems: comparison of biodiversity in two habitats

Information for learners

This section contains the assignment brief, tasks and evidence learners must complete to be submitted for assessment

7-9

Activity 2: Sand Dune analysis

Information for learners

This section contains the assignment brief, supporting data, tasks and evidence learners must complete to be submitted for assessment

10-13

Information for Supervisors: Managing Assessment

This section contains information on the controls which must be followed

14

Information for Supervisors: Accepted Changes to Assessment

15

Information for Supervisors: Mark Record sheets

This section includes the front authentication sheet which must be signed by both the candidate and supervisor and submitted along with the candidate evidence

The Mark Record Sheets must be returned to WJEC.

These will be completed by WJEC.

16-17

Assessment Grid for Unit 2 18


Either:

Activity One A: Investigation into how human activity can affect ecosystems:

comparison of biodiversity in two habitats

Eco-Systems is a company that has been asked to collect and analyse how a housing

development is impacting on nearby grassland for a local authority.

In order to do this they have decided to compare two similar habitats.

One habitat is grassland area near the housing development; the other is rural grassland

with no nearby development. You have been asked to carry out the comparison. You are

required to compare the number and types of organisms found in the two different habitats

and investigate how human activity can affect ecosystems, in particular the biodiversity

within these ecosystems. You will complete a scientific report on your investigation of the

two habitats for the company.

The company has also requested that you consider in more detail the inter-relationship

within the ecosystems in the grassland near the housing development and report separately

your findings.

Task 1: Plan your study

Plan to monitor the biodiversity of the two different habitats. You should consider the

properties of the habitat (e.g. weather conditions, pollution etc.). You should choose the

appropriate technique(s) to use and ensure that you consider any Health and Safety issues.

Task 2: Carry out your study

Follow your plan from task 1. Record any modifications to your plan as you carry out your

investigations. For each habitat you should record the species found and the numbers of

each of these species. You should also record any other data you think might be relevant,

such as soil pH, water oxygen levels and temperature of soil. It may be possible to record

the abundance of biotic indicators.

Task 3: Report on your investigation

Calculate species diversity for the two habitats you investigated. Process and display your

data in the most appropriate way. Draw conclusions about how human activity may have

affected the biodiversity in the two habitats you investigated. Comment on the range of

factors that affects biodiversity. Discuss the validity and reliability of your investigation and

any improvements that could be made.

Task 4: Report on the inter-relationships within ecosystems

For the grassland near the housing development you investigated explain:

a) how energy is transferred through the ecosystem;

b) the role of decomposers in the ecosystem.

Use the data you collected in your investigation to provide examples to support your

explanations.


OR

Activity One B: Investigation into how human activity can affect ecosystems:

comparison of biodiversity in two habitats

Ecosystems is a small company that has been asked to collect and analyse how a

recreational use is impacting on woodland for a local authority.

In order to do this they have decided to compare two similar habitats.

One habitat is woodland used for recreational purposes; the other is more remote woodland.

You have been asked to carry out the comparison. You are required to compare the number

and types of organisms found in the two different habitats and investigate how human

activity can affect ecosystems, in particular the biodiversity within these ecosystems. You will

complete a scientific report on your investigation of the two habitats for the company.

The company has also requested that you consider in more detail the inter-relationship

within the ecosystems in the grassland near the housing development and report separately

your findings.

Task 1: Plan your study

Plan to monitor the biodiversity of the two different habitats. You should consider the

properties of the habitat (e.g. weather conditions, pollution etc.). You should choose the

appropriate technique(s) to use and ensure that you consider any Health and Safety issues.

Task 2: Carry out your study

Follow your plan from task 1. Record any modifications to your plan as you carry out your

investigations. For each habitat you should record the species found and the numbers of

each of these species. You should also record any other data you think might be relevant,

such as soil pH, water oxygen levels and temperature of soil. It may be possible to record

the abundance of biotic indicators.

Task 3: Report on your investigation

Calculate species diversity for the two habitats you investigated. Process and display your

data in the most appropriate way. Draw conclusions about how human activity may have

affected the biodiversity in the two habitats you investigated. Comment on the range of

factors that affects biodiversity. Discuss the validity and reliability of your investigation and

any improvements that could be made.

Task 4: Report on the inter-relationships within ecosystems

For the grassland near the housing development you investigated explain:

c) how energy is transferred through the ecosystem;

d) the role of decomposers in the ecosystem.

Use the data you collected in your investigation to provide examples to support your

explanations.


LEARNER SUMMARY SHEET

Evidence for Activity 1A / Activity 1B

A summary of the tasks, evidence required and the assessment criteria you must evidence

is found below.

Task Number Evidence This is what you must produce.

Assessment Criteria You must make sure your work covers the following assessment criteria.

Controls This tells you the rules that your teacher must keep when you complete the tasks.

Task 1

Plan AC4.1; AC4.2

Time: 1 hour Resources: Access to appropriate ICT software;

access to appropriate health and safety advice; access to class notes NOT allowed. Supervision

You will be supervised throughout. Collaboration

Individual task. Feedback You cannot be given feedback on the work you

produce until it has been marked.

Task 2

Record of results, data tables

AC4.3; AC4.4 Time: Time for data recording: 1 hour in each

habitat. This does not include time to get to the habitat. It is permissible to split this task into two separate sessions. (one for each habitat). Resources: Plan from task 1; access to

appropriate fieldwork apparatus; access to class notes NOT allowed. Supervision




Task 3

Investigation report

AC1.4

AC2.1

AC2.2

AC4.5

AC4.6

AC4.7

Time: 2 hours Resources: Plan from task 1; data from task 2 ;

access to appropriate ICT hardware and software; access to class notes NOT allowed. Supervision




Task 4 Inter-relationship report

AC1.1

AC1.2

AC1.3

Time: 1 hour Resources: plan from task 1; data from task 2;

report from task 3; access to appropriate ICT hardware and software; access to class notes NOT allowed. Supervision





Activity Two: Sand dune data analysis

Scientists at a field-study centre on Anglesey have monitored the plant species present on

Newborough Warren sand dunes over a period of 20 years. The information they have

gathered is given below.

The Welsh government is interested in the continued conservation of these dunes and in

particular how biodiversity has developed at the dunes over the last 20 years. They have

asked for a detailed report on this particular ecosystem. The report must be in four specific

sections:

Section 1: Succession

Section 2: Specific species population analysis

Section 3: Species adaptation

Section 4: Conservation

Task 1: Produce section 1 of the report. For this section of the report, analyse the data

given about the species found in these sand dunes. Explain the process of successions that

has occurred at these dunes. In this section of the report you should clearly reference the

data provided, and also use your own knowledge and understanding of ecosystems

Task 2: Produce section 2 of the report. For this section of the report you have been asked

to make reference to a particular species: Marram grass. This section of the report should

focus on the percentage cover of Marram grass. You should use the data provided to show

how the population of Marram grass has developed in these dunes, discussing factors that

may have affected population numbers.

Task 3: Produce section 3 of the report. In this section of the report you can again use

Marram grass as an example. Discuss why the dunes are a good example of the adaptation

of a species (such as Marram Grass) and suggest how these adaptations may have resulted

from evolutionary change.

Task 4: Produce section 4 of the report. In this section of the report you should use the provided data to explain why the conservation of the sand dunes is necessary. You should describe different conservation methods, explain how human activity could impact on this ecosystem and discuss the implications of not undertaking conservation in this area.

Field study data


Species

% Cover of plant species after 20 years of study

Drift line

Embryo Dunes

Fore dunes

Mobile dune ridges

Wet slack

fixed dunes

climax vegetation

Sea Rocket 1 3 0 0 0 0 0

Prickly Saltwort

4 0 0 0 0 0 0

Sand couch 0 11 0 0 0 0 0

Marram grass

0 5 94 54 0 0 0

Red fescue 0 4 12 13 0 0 0

Ragwort 0 0 0 6 0 0 0

Groundsel 0 0 3 23 9 0 2

Dune pansy 0 0 0 17 0 0 0

Heath dog violet

0 0 0 24 5 0 0

Sea Holly 0 0 2 0 0 0 0

Restharrow 0 0 0 47 8 0 0

Yarrow 0 0 0 0 7 6 0

Ribwort plantain

0 0 0 0 11 6 0

White clover 0 0 0 0 5 0 2

Burnet rose 0 0 0 0 32 0 0

Creeping willow

0 0 0 0 0 76 0

Meadowsweet 0 0 0 0 0 42 0

Marsh pennywort

0 0 0 0 0 0 10

Buttercups 0 0 0 6 6 1 2

Silverweed 0 0 0 0 0 12 0

Sedges 0 0 0 0 0 14 0

Bramble 0 0 0 0 3 0 3

Gorse 0 0 0 0 0 0 0

Other trees 0 0 0 0 0 0 54

Other plants 0 0 0 1 1 5 10


Percent cover of species at fore dune region

Year

% cover of species at fore dune region

marram grass prickly saltwort sea holly groundsel

0 1 0 0 0

1 1 1 1 0

2 1 2 2 0

3 2 3 3 0

4 3 4 4 1

5 4 4 5 1

6 6 5 6 1

7 9 4 6 1

8 14 3 6 1

9 24 2 6 1

10 37 0 6 2

11 55 0 6 2

12 71 0 6 2

13 80 0 6 2

14 84 0 5 2

15 93 0 5 2

16 95 0 4 3

17 94 0 4 3

18 95 0 3 3

19 95 0 3 3

20 94 0 2 3


LEARNER SUMMARY SHEET

Evidence for Activity Two

A summary of the tasks, evidence required and the assessment criteria you must evidence

is found in the Learner Summary Sheet (below).

Task Number Evidence This is what you must produce.

Assessment Criteria You must make sure your work covers the following assessment criteria.

Controls This tells you the rules that your teacher must keep when you complete the tasks.

Task 1

Section 1 of report

AC1.7

Time: 1 hour Resources: Given resource; Access to

appropriate ICT software; access to class notes NOT allowed. Supervision


individual task. Feedback You cannot be given feedback on the work

you produce until it has been marked.

Task 2

Section 2 of report

AC1.4

AC1.5

Time 1 hour Resources: Report form task 1; Access to

given resource; Access to appropriate ICT software; access to class notes NOT

allowed. Supervision


individual task. Feedback You cannot be given feedback on the work


Task 3

Section 3 of report

AC1.6

Time 1 hour Resources: Report form task 1 and 2;

Access to given resource; Access to appropriate ICT software; access to class notes NOT allowed. Supervision


Individual task. Feedback You cannot be given feedback on the work

you produce until it has been marked. Task 4

Section 4 of report

AC2.1

AC2.2

AC3.1

AC3.2

AC3.3

AC3.4

AC4.6

Time 1 hour Resources: Report form task 1, 2 and 3;

Access to given resource; Access to appropriate ICT software; access to class. notes NOT allowed Supervision


Individual task. Feedback You cannot be given feedback on the work



UNIT 2: External Assessment

Managing the assessment

Activities

Candidates must complete:

Either Activity 1A or Activity 1B AND Activity 2.

WJEC provides alternative field work activities (1A / 1B) to help centres access suitable

locations to assess learners in their locality.

Time

Activity one: Task 1, task 3 and task 4, have a total time of 4 hours. Task 2 will require

learners to undertake field activities - time to travel to and complete these

activities is not included in the time allocation - 1 hour for data collection in

each habitat.

Activity two: 4 hours are available for the completion of this activity.

The time suggested for the tasks in the two activities, as set out in the Learner Summary

Table, takes account of the contribution of the tasks to the overall assessment requirements.

There can be no changes to the total time available for this assessment.

Resources

Learners must have access to the assignment brief, the Learner Summary Table, the unit

performance bands and necessary equipment/apparatus to undertake the field activities in

activity one. Details of any other resources that are required are stipulated in the Learner

Summary Table.

Supervision

Learners will be supervised whilst completing externally set assessment tasks. The Learner

Summary Tables specify the level of supervision required in each task of the activities in this

assessment. Centres must have in place systems to ensure learners cannot access

evidence they have been developing outside of supervised activities.

Authentication

Supervision is in place to ensure the authenticity of evidence produced for summative

assessment. Supervisors are not to provide input or guidance to learners during the

assessment time. This includes providing formative feedback on the evidence being

produced. Supervisors can provide guidance on the requirements of the task and remind

learners of the performance bands and how they can be interpreted. Supervisors must

intervene where there a health and safety issue is observed.

Learners can review and redraft evidence independently within the time controls for the

assessment.

Learners must sign a declaration to confirm that all evidence submitted for marking by WJEC

is their own work and that any sources used have been acknowledged.

Supervisors must sign a declaration to confirm that evidence submitted for marking by

WJEC was completed under the controlled conditions set out in the assessment.


Collaboration

Group work is not allowed for the assessment.

Marking

This assessment will be marked by WJEC. The work must be submitted for marking in the

summer of the academic year in which the assessment is set. The date for submission of

external assessment can be found in the WJEC Examination Timetable published for each

academic year on the WJEC website.

WJEC will use the performance bands found in unit 2 of the specification.

Accepted changes

Activity one

No changes are permitted to Activity 1A or 1B.

Activity two

No changes are permitted to this activity.


WJEC LEVEL 3 ENVIRONMENTAL SCIENCE

EXTERNAL ASSESSMENT: MARK RECORD SHEET UNIT 2: The Living Environment and conservation Centre Name: …………………………………………………………………………………… Centre Number: …………………………… Candidate’s Name: …………………………………………………………………………………… Candidate Number: ……………………………… I confirm that the evidence submitted for assessment has been produced by me without any assistance beyond that allowed. Candidate’s Signature: ………………………………………………… Date: ......../……../20…… I confirm that the evidence submitted by the learner has been produced under the controlled conditions set out in the qualification specification and model assignment. Supervisor’s Signature: ………………………………… Name (printed) …………………………………..……… Date: ......../……../20……

(MARK RECORD SHEET P1 of 2)

WJEC LEVEL 3 DIPLOMA / EXTENDED DIPLOMA IN ENVIRONMENTAL SCIENCE

EXTERNAL ASSESSMENT: MARK RECORD SHEET UNIT 2: The living environment and conservation Centre Name: …………………………………………… Centre Number: ……………… Candidate’s Name: ……………………………………… Candidate Number: ………….

Assessment Criteria

Evidence Page

number(s)

Activity 1A/1B

Activity 2 Total Unit mark

AC1.1 /3 /3

AC1.2 /6 /6

AC1.3 /6 /6

AC1.4 /6 /6

AC1.5 /6 /6

AC1.6 /6 /6

AC1.7 /6 /6

AC2.1 /4 /4

AC2.2 /9 /9 /18 /9

AC3.1 /4 /4

AC3.2 /9 /9

AC3.3 /6 /6

AC3.4 /9 /9

AC4.1 /6 /6

AC4.2 /6 /6

AC4.3 /6 /6

AC4.4 /4 /4

AC4.5 /6 /6

AC4.6 /6 /6

AC4.7 /6 /6

TOTAL /120

(MARK RECORD SHEET P2 of 2)

WJEC – Examiner USE ONLY


Assessment Grid

AC Activity 1A/1B Activity 2

1 2 3 4 1 2 3 4

AC1.1

AC1.2

AC1.3

AC1.4

AC1.5

AC1.6

AC1.7

AC2.1

AC2.2

AC3.1

AC3.2

AC3.3

AC3.4

AC4.1

AC4.2

AC4.3

AC4.4

AC4.5

AC4.6

AC4.6


5



Unit 2: The living environment and

conservation

Generic Mark Bands

Learning Outcome The learner will:

Assessment criteria The learner can:

Performance bands

Band 1 Band 2 Band 3

LO1 understand the inter-relationships within ecosystems

AC1.1 define an ecosystem

Gives a definition of an ecosystem

1-2

Gives a detailed description of an ecosystem

3

AC1.2 explain energy transfers between organisms in an ecosystem

Gives an explanation of how energy is transferred between organisms with some accuracy Low level explanations may not always clearly show reasoning

1-2

Gives a mainly accurate and coherent explanation showing some detailed reasoning of how energy is transferred between organisms

3-4

Gives an accurate and coherent explanation showing detailed reasoning of how energy is transferred between organisms

5-6

AC1.3 explain the role of decomposers in ecosystems

Gives an explanation of the role of decomposers in ecosystems with some accuracy Low level explanations may not always clearly show reasoning

1-2

Gives a mainly accurate and coherent explanation showing some detailed reasoning of the role of decomposers in ecosystems

3-4

Gives an accurate, detailed and coherent explanation of the role of decomposers in ecosystems

5-6

AC1.4 explain how factors affect ecosystem populations

Gives an explanation of how some factors affect biodiversity Low level explanations may not always clearly show reasoning

1-2

Gives a mainly accurate and coherent explanation showing some detailed reasoning of how a range of factors affect biodiversity

3-4

Gives an accurate, detailed and coherent explanation of how a range of factors affect biodiversity

5-6

AC1.5 analyse patterns in population data

Makes some appropriate analysis of population data

1-2

Makes a mostly appropriate analysis of population data showing some detailed reasoning

3-4

Makes an appropriate analysis of population data showing detailed reasoning

5-6

AC1.6 describe how variation within a species brings about change

Gives a description of some aspects of how variation within a species brings about change

1-2

Gives a mainly clear description of how variation within a species brings about change Some parts are in detail

3-4

Gives a clear and detailed description of how variation within a species brings about change

5-6

AC1.7 explain the process of succession

Gives an explanation of the process of succession with some accuracy Low level explanations may not always clearly show reasoning

1-2

Gives a mainly accurate and coherent explanation showing some detailed reasoning of the process of succession

3-4

Gives an accurate and coherent explanation showing detailed reasoning of the process of succession

5-6

Zero marks to be awarded where there is insufficient evidence to achieve a mark at band 1




Performance bands


LO2 understand how human activity impacts on ecosystems

AC2.1 describe human activity in an environment

Gives a description of some human activities in an environment. Some aspects of the description is relevant to the environment studied

1-2

Gives a clear, detailed and relevant description of human activities in an environment. The description is relevant to the environment studied

3-4

AC2.2 explain how human activity affects ecosystems

Gives an explanation of how human activity affects an ecosystem Low level explanations may not always clearly show reasoning

1-3

Gives a mainly accurate and coherent explanation showing some detailed reasoning of how human activity affects an ecosystem

4-5

Gives an accurate and coherent explanation showing detailed reasoning of how human activity affects an ecosystem

6-9





Performance bands


LO3 understand how ecosystems can be conserved

AC3.1 describe what is meant by conservation

Gives a mostly clear description of what is meant by conservation

1-2

Gives a clear and detailed description of what is meant by conservation

3-4

AC3.2 explain why conservation of ecosystems is necessary

Gives an explanation of why conservation of ecosystems is necessary Low level explanations may not always clearly show reasoning

1-2

Gives a mainly accurate and coherent explanation showing some detailed reasoning why conservation of ecosystems is necessary

3-6

Gives an accurate and coherent explanation showing detailed reasoning why conservation of ecosystems is necessary

7-9

AC3.3 describe different conservation methods

Gives a description of some appropriate methods of conservation

1-2

Gives a mainly clear description of appropriate methods of conservation Some parts are in detail

3-4

Gives a clear and detailed description of appropriate methods of conservation

5-6

AC3.4 explain the reasons for extinction

Gives an explanation of some relevant reasons for extinction Low level explanations may not always clearly show reasoning

1-3

Gives a mainly accurate and coherent explanation showing some detailed reasoning of relevant reasons for extinction

4-6

Gives an accurate and coherent explanation showing detailed reasoning of relevant reasons for extinction

7-9





Performance bands


LO4 be able to monitor ecosystems

AC4.1 plan to obtain data about ecosystems

Identifies some information to collect Identifies some appropriate procedures and equipment to collect information Sets some achievable times to complete some aspects of the plan Devises a proforma to collect some suitable information

1-2

Identifies most information to collect Identifies mainly appropriate procedures and equipment to collect information Sets achievable times to complete most aspects of the plan Devises a mainly suitable proforma to collect most required information

3-4

Identifies the information to collect Identifies appropriate procedures and equipment to collect the information Sets achievable times to complete all aspects of the plan Devises a suitable proforma to collect all the required information

5-6

AC4.2 draw up a health and safety risk assessment

Identifies some hazards and risks to health and safety Suggests some suitable control measures Records some parts of risk assessment accurately

1-2

Identifies significant hazards and risks to safety. Suggests some suitable control measures for significant hazards and risks to health and safety Records most aspects of the risk assessment accurately and clearly

3-4

Identifies the significant hazards and risks to safety. Suggests suitable control measures for hazards and risks to health and safety Records clearly and accurately the risk assessment

5-6

AC4.3 obtain data about ecosystems

Obtains some suitable data about ecosystems Some data is obtained is within expected tolerance of procedures used to obtain data

1-2

Obtains mostly suitable and sufficient data about ecosystems Most data is obtained is within expected tolerance of procedures used to obtain data

3-4

Obtains suitable and sufficient data about ecosystems Consistently obtains data within expected tolerance of procedures used to obtain data

5-6




Performance bands


LO4 continued AC4.4 record data from ecosystems

Some key data is recorded Entries are generally legible Some data recorded to appropriate precision Some records are clear

1

Most key data is recorded Most entries are legible Most data recorded to appropriate precision Records are mostly clearly and logically presented

2-3

key data is recorded All entries are legible All data recorded to appropriate precision Records are clearly and logically presented

4

AC4.5 process data from investigations

Uses some suitable methods to process data Some aspects of graphs/calculations are clearly presented Makes a limited use of significant figures

1-2

Uses suitable methods to mostly accurately process data Graphs/calculations are mostly clearly and logically presented Makes some appropriate and accurate use of significant figures

3-4

Consistently uses suitable methods to accurately process data Graphs/calculations are clearly and logically presented Consistently makes appropriate and accurate use of significant figures

5-6

AC4.6 assess how human activity has affected an ecosystem

Gives an assessment of how human activity has affected biodiversity with reference to a limited range of relevant factors, with some reasoned judgements

1-2

Gives an assessment of how human activity has affected biodiversity with reference to relevant factors, with mainly reasoned judgements Some parts are in detail

3-4

Gives a detailed assessment of how human activity has affected biodiversity with reference to a range of relevant factors, with reasoned judgements

5-6

AC4.7 evaluate data and procedures

Makes some suitable judgements about data and procedures some Evaluation may be weighed towards data or procedures

1-2

Makes mainly suitable judgements showing clear reasoning about data and procedures against a range of criteria

3-4

Makes suitable judgements showing clear and detailed reasoning about data and procedures against a range of criteria

5-6


WJEC LEVEL 3

Diploma in Environmental Science / Extended Diploma in Environmental Science

SPECIMEN ASSESSMENT MATERIALS

External Assessment

UNIT 4 Scientific principles and the environment


Unit 4 Details of assessment

Unit 4 is assessed through one written two hour (90 marks) examination available in the summer of each year. Unit 4 is intended to examine the underpinning scientific concepts of units 1 to 3. Each paper will consist of two sections (Section A and B). All questions in the paper will be compulsory.

Section A

Questions will be based upon a pre-release article and connected specification content.

The pre-release article is intended to provide an environmental context for questions in section A. It will also contain environmental data and information for analysis and/or evaluation.

Between 22 and 25 marks will be available for Section A.

Section B

Questions set within an environmental context related to units 1 - 3. All questions will require the learner to engage with stimulus material. Stimulus material may include images, diagrams, photographs, graphs and information.

All papers will include synoptic questions that link to the context of units 1 to 3.

Assessment criteria from each learning outcome from unit 4 will be assessed in the

examination. Marks will be apportioned to each learning outcome of unit 4 as follows:

Learning

Outcome AO1 AO2 AO3 AO4 Total

Allowed

range 18-24 18-24 18-24 23-29 90

Unit 4 Administration of pre-release material

The pre-release article will be available for centres to download from the WJEC website from

the last week of April. Teachers can use the pre-release material in lessons with learners

after it has been released on the WJEC website.

Learners will be issued with a clean copy of the pre-release article for the examination.

Learners are not permitted to take an annotated copy of the pre-release article into the

examination.




Resource Folder (Pre-release Article)

For use with unit 4 Scientific principles and the environment examination

Specimen


Air Pollution

What is air pollution?

Air quality and the formulation and transport of air pollution is a highly complex subject that is

dependent on many things including the weather, the natural environment, demographics,

random and dynamic events, many of which cannot be predicted or forecast. Air pollution is 5

both naturally occurring (e.g. sulfurous gases from volcanos, smoke from forest fires) and

man-made (e.g. vehicle exhaust and power station emissions).

Those people who were around in the 1940s and 1950s will remember the smog and “pea-

soupers”, most notably the great London smog of 1952 which contributed to the death of up

to 5 000 people. Thankfully those days are gone (in the UK at least) and today’s air pollution 10

is very different. Unlike the great smogs of the 1950s, air pollution is now largely invisible

and often without odour. The main pollutants in our towns and cities are oxides of nitrogen

(NOx), respiratory particles (known as PM10), ozone (O3), volatile organic compounds

(VOCs), sulphur dioxide (SO2) and carbon monoxide (CO). There are, of course, many more

air-pollutants, especially near industrial plants such as chemical works, power stations etc. 15

Although we no longer suffer from the fatal smogs of the 1950s, air pollution still has many

serious consequences that impact on the environment and human health - particularly the

very young, the very old and those who suffer from asthma and other chronic respiratory

illnesses. Air pollution has been linked to such illnesses and proven to exacerbate the

degree of suffering. Other air pollutants, such as benzene have been linked with different 20

types of cancers in humans and animals.

Particulate matter, especially very fine particles (smaller than 10 microns – known as PM10),

is thought to have a very large impact on human health and is one of the major problems

facing environmental professionals. PM10 particles and even smaller fractions (PM2.5) can

reach deep into our lungs and can cause severe respiratory problems as well as possibly 25

contributing to many other conditions and diseases.

In towns and cities, the many individual pollutants can combine to form a "cocktail" which,

under certain weather conditions (i.e. still, hot summer days), can lead to modern day smogs

known as "photochemical smog". This is common in all large cities during this type of

weather; some of the best-known "smog cities" include Los Angeles, Mexico City and, closer 30

to home, even London.

Tropospheric ozone formation

Ozone (O3) is a constituent of the troposphere (it is also an important constituent of regions

of the stratosphere). Photochemical and chemical reactions involving it drive many of the

chemical processes that occur in the atmosphere by day and by night. 35

Although life on earth would not be possible without the ozone layer, tropospheric ozone is

regarded as a secondary pollutant. The majority of tropospheric ozone formation occurs

when nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)

react in the atmosphere in the presence of ultraviolet light. NOx, CO, and VOCs are called

ozone precursors. Motor vehicle exhaust, industrial emissions, and chemical solvents are 40

the major anthropogenic sources of these chemicals. Another source is windshield washer

fluid. Although these precursors often originate in urban areas, winds can carry NOx

hundreds of kilometres, causing ozone formation to occur in less populated regions as well.

Methane, a VOC whose atmospheric concentration has increased tremendously during the


last century, contributes to ozone formation but on a global scale rather than in local or 45

regional photochemical smog episodes. In situations where this exclusion of methane from

the VOC group of substances is not obvious, the term Non-Methane VOC (NMVOC) is often

used.

The chemical reactions involved in tropospheric ozone formation are a series of complex

cycles in which carbon monoxide and VOCs are oxidised to water vapour and carbon 50

dioxide. Some of these reactions are listed below.

OH + CO → HOCO

HOCO + O2 → HO2 + CO2

HO2 + NO → OH + NO2

NO2 + hf → NO + O* 55

O* + O2 → O3

The problem with tropospheric ozone

Ozone is a powerful oxidizing agent in the atmosphere readily reacting with other chemical compounds to make many different toxic oxides. Ozone is also known to have the following health effects (among others) at concentrations common in urban air: 60

Irritation of the respiratory system, causing coughing, throat irritation, and/or an

uncomfortable sensation in the chest.

Reduced lung function, making it more difficult to breathe deeply and vigorously.

Breathing may become more rapid and more shallow than normal, and a person's

ability to engage in vigorous activities may be limited. 65

Tropospheric ozone causes approximately 21 000 premature deaths per year in 25 countries

in the European Union. (WHO, 2008).

Tropospheric ozone is also a greenhouse gas.

What is the daily air quality index?

In deriving a daily air pollution indicator an approach must be developed to combine 70

concentrations of different measured pollutants. A number of alternative approaches have

been proposed to present air pollution information from a range of pollutants in a single

index. The most widely known of these is the United States Pollution Standards Index which

is used in a number of countries. In the UK, DEFRA have established an Air Pollution Public

Information System. DEFRA's System is based upon three air pollution thresholds 75

(Standard, Information and Alert) and four bands (Low, Moderate, High and Very High

Pollution). The effects on sensitive individuals described for 'high' levels of pollution may

worsen. Table 1 describes the possible health effects associated with different bands of air

pollution.

80


Table 1 Banding and health effects

Banding Index Health Effects

Low 1, 2, or 3 Effects are unlikely to be noticed even by individuals who know they are sensitive to air pollutants.

Moderate 4, 5, or 6 Mild effects, unlikely to require action, may be noticed amongst sensitive individuals.

High 7, 8, or 9

Significant effects may be noticed by sensitive individuals and action to avoid or reduce these effects may be needed (e.g. reducing exposure by spending less time in polluted areas outdoors). Asthmatics will find that their 'reliever' inhaler is likely to reverse the effects on the lung.

Very High

10

Employing the DEFRA Air Pollution Public Information System limits the Indicator to those

pollutants for which there are potential acute health effects. An indicator, based upon this

approach does not therefore include pollutants in the National Strategy with only chronic

health impacts: benzene, 1,3-butadiene and lead. 85

Combining chronic and acute health effects from air pollution within a single indicator would

require impacts to be evaluated in terms of a life-time or annual risk. The resulting indicator

would be extremely complex to calculate and highly dependent upon the assumptions

employed. In particular, long-term exposure to each pollutant would need to be assessed. A

recent study (Development of Aggregated UK Indicators of Air Quality, 1998, DETR, HMSO) 90

concluded that there is no current methodology for estimating population exposure [to air

pollution] which is sufficiently robust to derive a meaningful indicator.

An Indicator based upon the frequency of pollution episodes (and potential acute health

effects), as opposed to one of chronic air pollution toxicity is considered to be more:

scientifically robust; 95

readily understood by the public;

readily reflects at least some public concerns (air pollution as a precursor to acute

respiratory disease).

The Index is therefore based upon the five pollutants included in the DEFRA Air Pollution

Public Information System. If, in the future, the National Air Quality Strategy is extended to 100

include other pollutants with acute health effects, it would be appropriate to re-examine the

pollutants to be included both within the Indicator and Public Information System. If the

national standards and/or Public Information System were amended, for example to reflect

improved scientific knowledge of air pollution health impacts, it would be necessary to re-

examine the Indicator. 105

The overall daily air quality index for Swansea or an individual site is calculated from the

highest concentration of the five pollutants included within the banding system. All data

presented within these pages is shown as micro grams per cubic meter of air (µgm-3).


Table 2 Boundaries between index points for each pollutant

Band Index

Ozone Running 8 hourly mean

Nitrogen dioxide hourly mean

µgm-3 µgm-3

Low 1 0-33 0-66

Low 2 34-65 67-133

Low 3 66-99 134-199

Moderate 4 100-120 200-267

Moderate 5 121-140 268-334

Moderate 6 141-159 335-399

High 7 160-187 400-467

High 8 188-213 468-534

High 9 214-239 535-599

Very high 10 240 or more

600 or more

110


Air quality in Swansea

The following measurements show data on air quality and meteorological data in Swansea

for two periods between 14th and 21st July 2013. There was no rainfall in this period.

Chart A UV Intensity in Swansea 14 – 21 July 2013

Chart B Wind speed in Swansea 14 – 21 July 2013 115


Chart C Wind direction at 10 m in Swansea 14 – 21 July 2013

Chart D Ozone levels in Swansea14 – 21 July 2013

120

Chart E Nitrogen dioxide levels in Swansea14 – 21 July 2013


Ozone Levels

Every 30 minutes, the 8 hour mean value of ozone is updated . The running 8 hour mean

level of ozone during the period 17-19 July is shown in Table 2. These values are obtained 125

by averaging all the ozone reading in the previous 8 hours.

Table 3 Ozone levels – Running 8 hour mean values

Time

Ozone (8 hour mean value)

µg/m3

17/07/2013 18/07/2013 19/07/2013

00:00 79.8697 73.34758 112.6415

00:30 78.50364 71.30697 109.6627

01:00 77.45303 68.90697 106.5339

01:30 76.3 66.75333 104.5797

02:00 75.30121 64.9297 101.2015

02:30 74.48758 62.50121 96.66697

03:00 72.85212 60.90848 93.04303

03:30 71.52394 60.16182 90.09818

04:00 69.21061 60.23939 87.43182

04:30 67.07515 61.4597 84.91848

05:00 66.32697 60.96364 82.41212

05:30 64.81727 59.7197 81.77545

06:00 62.64364 59.74667 81.47273

06:30 60.95576 60.31182 81.12394

07:00 59.13394 60.40515 78.53212

07:30 57.21848 60.45636 75.42333

08:00 56.18333 60.08667 72.15152

08:30 55.43606 61.08424 70.0097

09:00 54.5497 61.85515 68.41848

09:30 53.74879 62.94455 67.1497

10:00 55.14879 63.27939 66.39939

10:30 56.52909 63.55091 66.06848

11:00 60.8382 63.60242 66.04543

11:30 72.9651 63.70244 66.11854


12:00 76.8697 63.75091 66.24303

12:30 78.50364 63.85545 66.62061

13:00 77.45303 63.9703 66.77667

13:30 76.3 63.95273 66.82939

14:00 75.30121 63.75455 66.97697

14:30 74.48758 64.77515 67.1103

15:00 72.85212 67.40303 67.41333

15:30 71.52394 69.81636 67.40879

16:00 69.21061 72.95758 67.70303

16:30 67.07515 75.74788 68.00545

17:00 66.32697 79.00909 68.6697

17:30 64.81727 83.1197 69.39273

18:00 62.64364 86.78242 70.71636

18:30 60.95576 90.3 72.43152

19:00 59.13394 93.34182 73.77788

19:30 57.21848 98.2997 74.87727

20:00 56.18333 102.4436 76.67879

20:30 55.43606 105.6509 77.57242

21:00 54.5497 108.1788 77.30636

21:30 53.74879 110.7879 76.37636

22:00 53.14879 112.6836 75.96879

22:30 52.52909 113.5503 75.66242

23:00 52.25273 112.457 75.37333

23:30 53.53606 111.2615 74.69333


Candidate Name Centre Number Candidate Number


WJEC Level 3 Extended Diploma in Environmental Science

SPECIMEN EXTERNAL ASSESSMENT

AM/PM xxxday xx June 20**

Unit 4: Scientific principles and the environment (2 hours)

Instructions to candidates

Answer all questions.

Write your answers in the spaces provided in this

booklet.

Information for candidates

The total mark for the paper is 90 marks.

You are reminded of the necessity of good English

and orderly presentation of your answers.

The number of marks is given in brackets at the end of each question or part question.

Questions in section A are based on the pre-release article.

You will need the resource folder that contains the pre-release article.

You will need a calculator and ruler for this exam.

You should show your workings to calculations.

For Examiner’s use

only

Section Question Maximum

Mark

Mark

Awarded

A 1-4 25

B 5 10

6 14

7 14

8 7

9 5

10 10

11 5

Total 90


Section A

Answer all questions in the spaces provided.

These questions are based upon the pre-release article

1. (a) ‘Ozone (O3) is a constituent of the troposphere (it is also an important constituent

of some regions of the stratosphere)’ (lines 33-34).

The diagram that follows shows the structure of the atmosphere. Label the

following diagram (not drawn to scale) using the following terms: [3]

stratopause troposphere stratosphere ozone layer tropopause


(b) “Life on earth would be impossible without the ozone layer” (line 36). Explain this statement. [3] ……………………………………………………………………..…………….…. ……………………………………………………………………..…....……….…. ……………………………………………………………………………..….….…. …………………………………………….…………………………..………….…. ………………………………………………….………………………..……….….

2. (a) This question refers to the section on tropospheric ozone formation (lines 33-56).

(i) ‘Photochemical and chemical reactions drive many of the chemical processes

that occur in the atmosphere’ (lines 34-35). State what you understand by a photochemical reaction. [2]

............................................................................................................................ ............................................................................................................................ (ii) State what is indicated by the ‘*’ in the formula ‘O*’ (line 55). [1] ............................................................................................................................

(iii) Show a dot and cross diagram for the OH(g) free radical (line 34). [1] (iv) With reference to one of the equations in the reaction sequence (lines 52-56),

explain what is meant by a propagation step. [3] ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………………..

(v) The sequence of reactions (lines 52-56) can be summarised as a single

balanced chemical equation. Complete the equation below. [2]

CO + ……O2 + hν → …………. + ……………..


(b) ‘The majority of tropospheric ozone formation occurs ..…. in the presence of ultraviolet light’ (lines 37-39).

(i) Support this statement by making reference to suitable air quality graphs for

Swansea. (page 32-33) [2]

………………………………………………………………………………………….

…………………………………………………………………………………………..

………………………………………………………………………………………….

………………………………………………………………………………………….

…………………………………………………………………………………………..

(ii) Explain why ultraviolet light is required in this process by making reference to the atmospheric reactions (lines 52-56). [2]

………………………………………………………….……………………………….

………………………………………………………….………………………………..

……………………………………………………………………………………………

..…………………………………………………………………………………………..

3. The running eight hour mean ozone data was obtained by averaging the ozone

levels recorded every 30 minutes over an eight hour period. The raw data used to obtain the mean 55.14879 µg/m3 (Date 17/07/2013. Time

10:00) was:

78.23, 77.34, 78.62, 63.17, 41.96, 51.63, 53.30, 42.53, 40.9, 35.84, 41.7, 65.63,55.27, 39.3, 47.53, 39.78, 50.82, 57.87, 44.81, 43.06, 46.84, 44.61, 47.15, 50.23, 50.03, 56.26, 54.49, 51.87, 60.25, 56.67, 58.99, 58.77, 68.46

(i) Rewrite the mean value showing the correct number of significant figures. [1]

……………… µg/m3


(ii) It is sometimes more useful to quote concentration in parts per billion rather than units of μg/m3. Convert 100 μg/m3 of ozone to units of ppb, if the temperature is 20oC. [3] Use the formula:

ppb x 12.187 x M (273 + °C)

where M = molar mass of substance; Ar(O) =16

Answer ……………….ppm 4. One of the reactions of ozone which takes place in the atmosphere is:

C2H4 + O3 2CO + 2HO2 + other products

Use oxidation numbers to explain whether the carbon atom is oxidised or reduced in this reaction. [2] ………………………………………………………….………………………………..…..… ……………………………………………………………………………………….….……… ..……………………………………………………………………………………..….………

μg/m3 =


Section B Answer all questions in the spaces provided.

5. Heat energy is lost from houses.

(a) The table shows the percentage of the external area and percentage heat loss from different parts of a house.

Area (%) Heat loss (%)

Roof 25 25

Windows 5 20

Walls (air cavity) 48 30

Floor 22 15

(i) Explain how cavity wall insulation reduces heat loss through the walls. [2]

…...................................................................................................................

…………………….……….……………………………………………………… …………………….……….………………………………………………………

(ii) Use the information in the table to determine which part of the house allows the greatest heat energy loss per unit area. Explain why this is the case. [2]

................................................................................................................... ……………….……….…………………………………….……………………

..................................................................................................................

(iii) Explain why double glazing reduces the amount of heat lost through a

window. [2]

..................................................................................................................... ………………….……….………………………………………………………… …..................................................................................................................


(b) The graph shows the effect of gap size on the rate of heat loss when the outside temperature is 10 °C lower than that inside the house.

(i) Show on the graph, the optimum gap between the panes to reduce heat loss.

[1] (ii) Most modern double glazed units use a gap of 20 mm. The total window area

for a house is 20 m2.

Use the graph to estimate the heat (energy) loss in eight hours. [3] Include the unit in your answer.

Answer …………. ……….


6. There are fears of winter black-outs in the UK due to insufficient capacity to generate electricity. It is proposed that the site of the derelict Battersea power station in central London be used to build a new power generation plant. There are two options for the new power station - a coal powered station or a nuclear powered station.

©Shutterstock/Iain McGillivray

(a) Compare and contrast the two options for generating power. Discuss whether

central London is a suitable location for such power stations. [7]

….....................................................................................................................

…………………….……….…………………………………………………………

……..................................................................................................................

……..................................................................................................................

…………………….……….…………………………………………………………

……..................................................................................................................

……..................................................................................................................

….………………….……….………………………………………..…….…………

……..................................................................................................................

……..................................................................................................................

…………………….……….…………………………………………………………

……..................................................................................................................

……..................................................................................................................

……...................................................................................................................


(b) Coal produces 25 GJ of thermal energy per tonne (1000 kg) and a 35% efficient coal power station produces 3.6 GW of electrical power.

(i) Differentiate between the terms power and energy used in this sentence. [2]

……..................................................................................................................

……...................................................................................................................

..…………………….……….…………………………………………………………

(ii) Calculate the mass of coal burned per second by the power station. [3]

(iii) Each GJ of energy produced by the power station releases 2.1 kg of pollutants (other than CO2) into the atmosphere. Calculate the mass of these other pollutants produced by the power station every day.

[2]

Answer …………………………


7. The ‘hygenia Aquasnap’ is a user friendly, self-contained water sampling device. It is used as a water testing device for testing the biomass of living organisms in cultures, water, and waste waters. The test relies on the fact that all living things require energy and usually this is used in the form of the ‘universal’ energy molecule ATP.

(a) The schematic diagram below shows the molecule ATP that the ‘aqasnap’ detects.

(i) State the name of the parts labelled A, B and C. [3] A ………………………………………… B ……………………………………….… C …………………………………………. (ii) Describe how energy is released from ATP. [3] ……………………………………………………………………………………… ………………………………………………………………………………………

…………………………………………………………………………………………

C

B

A

http://www.google.co.uk/imgres?biw=1301&bih=548&tbm=isch&tbnid=L7DiTOLkTmVgfM:&imgrefurl=http://www.biology-books.com/Standard/standard.html&docid=4YbHvk4VEGZ5SM&imgurl=http://www.biology-books.com/Standard/ch2/30a.jpg&w=450&h=140&ei=wVdeUurjGJGb0wX2mYGQDg&zoom=1&ved=1t:3588,r:48,s:0,i:232&iact=rc&page=4&tbnh=112&tbnw=310&start=40&ndsp=15&tx=151.09527587890625&ty=51.28572082519531


(iii) Give three advantages of ATP as an energy source. [3]

1. ……………………………………………………………………………………

2. …………………………………………………………………………………… 3. …………………………………………………………………………………… (iv) Name two process inside a cell that requires energy in the form of ATP. [2] 1. …………………………………………………….. 2. ……………………………………………………..

(b) The ATP detected by the aquasnap is produced in small steps in the process of

respiration. The main steps are outlined below.

Describe the reactions that link glycolysis to the Krebs cycle. [3]

…………………………………………………………………………………………

…………………………………………………………………………………………

…………………………………………………………………………………………

Glycolysis

Krebs cycle

Electron

transport

chain

Link reaction


8) Throughout Indonesia tropical forests have been extensively cleared to make land available for agriculture. In these forests nitrogen was made available to growing plants by the action of bacteria. (a) Explain how the clearing of forests can affect the amount of carbon dioxide in the

atmosphere. [2]

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………… (b) Describe the role of bacteria in making the nitrogen in dead leaves available. [5]

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………… ……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

…………………………………………………………………………………………… ……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………


9. Iron is found naturally in some underground water. At sources where natural iron levels are high, treatment plants are provided to remove it. In the UK, the national

requirements specify a maximum of 200 gFe/l (0.200 ppm of iron) in drinking water at the consumer taps.

A water sample taken from a consumer water tap is analysed by atomic absorption spectroscopy at 248.3 nm for iron. The absorbance of the water, after twofold dilution, was 0.430 at 248.3 nm.

Conc of Fe (ppm)

Absorbance

0.00 0.000

0.59 0.115

1.78 0.335

2.97 0.530

4.15 0.670

5.93 0.815

Construct a suitable calibration curve and use this curve to determine the concentration of the iron in the original water sample. State whether this water sample is within national requirements. [5] The graph paper for this question is on the facing page.

………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………………


Graph paper for use with question 9.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.5 1 1.5 2 2.5 3 3.5 4


10. The following table contains information about two different pesticides.

Common name

Pesticide Movement

Rating

Soil half-life

(days)

Water solubility

(mg/l)

Sorption coefficient

Koc

log10(Sorption coefficient) log10(Koc)

DDT Extremely

Low 2000 0.0055 2 000 000 6.301

dicamba salt Very High 14 400 000 2 0.301

(a) (i) The soil DDT concentration of DDT was found to be in 12.8 ppm. Estimate the concentration in the soil after 6 000 days. [2]

Answer ……………….

(ii) DDT was banned from use in the UK in 1984. Thirteen years after DDT was banned, it could be still detected in soil samples.

Explain this observation in light of the information given above. [3]

..…….…………………………………………………………………………….. ……..……………………………………………………………………..….…… …………………………………………………………………………….………. ……………………………………………………………………..………………. (b) Explain which pesticide is likely to show higher concentrations in ground water

near application sites. [1] ……………………………………………………………………………………………. ……………………………………………………………………………………………. (c) Half-lives for pesticides in the environment are sensitive to a number of factors

and should only be treated as a guide. State two factors that may affect the half-life of a pesticide in soil. [2]

……………………………………………………………………………………….……. …………………………………………………………………………………….……….

………………………………………………………………………………….………….


(d) The pesticide movement rate is determined by making use of Groundwater Ubiquity (GUS) scores. If the GUS value is higher than 4.0, then the pesticide has a very high potential to move towards groundwater.

Use the following expression to calculate the GUS value for Diacamba salt and confirm that it should be ranked as ‘very high’. [1]

GUS = log10(half-life) x [4 - log10(Koc)].

…………………………………………………………………………………………… ……………………………………………………………………………………………

(e) State which of the following rate equations describes the rate of decomposition of DDT in soil. [1] A rate = k[DDT]0 B rate =k[DDT]1 C rate =k[DDT]2 D rate =k[DDT]3 ………………….


11. Copper in high concentrations can be toxic. Copper complexes, such as copper tetraaqa(ethylenediamine)copper(II) and aqua(triethanolammine)copper(II) have been developed that serve to decrease the availability of the copper ion in the water column through chelation. Ionic copper in solution normally forms complexes with carbonates. The chelated copper complexes prevent these copper carbonates from forming, thereby decreasing the toxicity to non-target organisms including humans and fish.

Tetraaqa(ethylenediamine)copper(II)

Aqua(triethanolamine)copper(II)

(a) Explain the term chelating agent with reference to ethylenediamine. [2]

……………………………………………………………………………………………

…………………………………………………………………………………………….


(b) Give the coordination number of the copper in both the

tetraaqa(ethylenediamine)copper(II) and the aqua(triethanolamine)copper(II) complexes. [1]

…………………………………………………………………………………………….

…………………………………………………………………………………………….

(c) The pH of pond water on an old copper smelting site has a pH of 4.8.

(i) Define pH. [1]

……………………………………………………………………………………….

……………………………………………………………………………………….

(ii) Calculate the H+ concentration of the water. [1]

…………… mol dm-3




Unit 4: Scientific principles and the environment

Specimen Mark Scheme


SECTION A

Question Marking point Clarification Mark

1. (a) (b)

All labelling points correct (3) 3 or 4 labelling points correct (2) 2 points correct (1) Ozone layer/stratospheric ozone (is referred to) (1) Ozone absorbs UV light (1) preventing penetration to ground level where it damages DNA in organisms (1)

Less than two labelling points correct (0)

3

3

2 (a) (i) (ii) (iii)

(iv)

(v) (b) (i) (ii)

A chemical reaction initiated by the absorption (1) of energy in the form of light/light energy/electromagnetic radiation(1) Activated oxygen/ excited oxygen (1)

A step in a free radical reaction mechanism (1) in which has free radical reactant and free radical product. (1)

e.g. HOCO + O2 → HO2 + CO2 (1) 2, CO2, O3 Graph A shows a periodic change in UV levels (between day and night) (1) These periodic changes are mirrored in similar periodic variation in the ozone levels in graph D (1) Step 4 involves the absorption of light from the UV part of the spectrum (1). Without the formation of (activated/excited) oxygen, step 5 could not take place (1)

7 electrons must be shown around the O atom.

2 marks all correct, 1 mark products correct Graphs A and D should be referred to in each case Two points must be correctly and coherently connected for 2 marks

2

1

1

3

2

2

2



3 (i) (ii)

55.15 ppb = µgm-3 x (273 + oC) (1) 12.187 x M M(O3) = 3 x 16.00 = 48.00 (1) ppb = 100 x 293 = 50.09 (1) 12.187x48

1 3

4 C2H4 ON(C) = -2 CO ON(C) = +2 Carbon is oxidised

2 marks. The answer must give correct ON and correct conclusion (oxidised) 1 mark can be awarded for two parts correct. If the conclusion is deemed correct in spite of one wrong oxidation number then the answer must be consistent with the candidate’s oxidation numbers.

2

TOTAL SECTION A 25


SECTION B


5. (a) (i) (ii) (iii) (b) (i) (ii)

Cavity wall filling involves using packing cavity with a material with poor heat conductor/material with high U value (1) Inhibiting heat flow so reducing % heat loss. owtee (1) Windows (1) Have higher thermal conductivity/ lower thermal resistance/ lower U value (than other parts of the house). (1) Trapped layer of air/air between two sheets of glass (1) reduces thermal conductivity/increases thermal resistance thus reducing heat loss / which is poor conductor of heat. (1) Graph marked at 30 mm. Heat loss = 2.85 x 8 x 60 x 60 x 20 = 1624320 (2) Joules. (1) or =2.85 x 8 x 20 = 451.2 (2) Wh (1)

Two points must be correctly and coherently connected for 2 marks. Do not accept: easier passage of heat than other parts of house. Points must be correctly and clearly connected for 2 marks. Accept mark at 31 mm. If correct calculation shown but wrong answer recorded. (1) Other appropriate units may be used e.g. kWh.

2

2

2

1

3



6 (a)

(b) (i) (ii)

(iii)

Coal Any two from:

Acid rain

Global warming/CO2 emitting

Other specified pollution e.g. smog & carcinogenic Particulates

Causes asthma

Can be very high output power. Nuclear Any two from:

Danger of accident/leak in high population area

Decommissioning very expensive, waste radioactive for many years and must be contained

Expensive in general

no CO2 emission, can be very high output power.

Local points Any three from:

Large number of local jobs (and plenty of people to fill vacancies),

Plenty of water available (Thames),

Less need for long power cables,

Good rail links,

Very expensive land prices,

Causes asthma (but cannot be counted twice),

Risk of radioactive leak in high population area (but cannot be counted twice),

Reduces already poor air quality in London etc.

Energy is the capacity to do work. (1) Power is the rate at which work is done, or energy is transmitted. (1) 3.6 GW = 3.6 GJs-1 3.6 x 100/35 = 10.3 (GJs-)1 of energy from coal (1) 10.3/25 (1) = 0.41 tonnes per second. (1) Energy produced per day = 3.6x60x60x24= 311 040 GJ (1) Mass pollutants = 311 040 x 2.1 =653 184 kg/ (1)

Incorrect answer but all workings correct = 2m Allow error carried forward to second and third steps Allow error carried forward Also accept 653.184/653 tonnes

7

2

3

2



7 (a) (i) (ii) (iii) (iv)

A - Adenine B - Ribose C – Phosphate ATP converted to ADP + Phosphate ATP - hydrolysed High energy phosphate bonds ATPase 30kJ mol-1 Energy released in small amounts Only requires one enzyme Universal/common energy source Any two from – Protein synthesis Biosynthesis Active transport Nerve conduction Cell division

Nitrogenous or organic base Pentose. Easily moves across a membrane Easily regenerated Do not accept: metabolism growth movement

3

3

3

2

(b) Pyruvate is converted to acetyl /Pyruvic acid is converted to a two carbon structure.(1) Reduced NAD formed/dehydrogenation Loss of carbon dioxide/decarboxylation Forms acetyl CoA

3

8 (a) (b)

Reduced photosynthesis / reduced carbon dioxide uptake (1) which will in turn lead to increase in carbon dioxide in atmosphere (1) Amino acids/protein in plants contain nitrogen (1) Decomposition / Putrefaction occurs caused by saprophytic bacteria) (1) produce ammonium compounds (1) and any two of:

Deamination of protein occurs

Nitrifying bacteria /nitrobacter produces nitrites (nitrification)

Nitrosomas - produces nitrates – absorbed by plants

Points must be coherently linked to obtain 2 marks

2

3

2



9 Graph constructed correctly: Axis (X = conc (ppm), Y absorbance) and must also be correctly labelled. (1) Suitable scale. (1) Best fit curve used. (1) Concentration of diluted Fe3+ (2.05; 2.00-2.10 = allowed range). (1) Iron sample = 4.20 and is outside national guidelines. (1) Completed calibration curve for reference purposes is shown in appendix A.

If the axis is wrong way around but otherwise drawn correctly (1). Use candidate workings from graph in marking other parts. If best straight line is used give no marks for this point. If straight calibration line used then mark from this point on using the value candidate should get if he/she correctly uses the straight line to obtain concentration. Must be 2x answer for diluted sample.

5



10 (a) (i)

(ii)

(b)

(c) (d) (e)

Three half-lives (1) 1.6 ppm (1) Any three of:

It has an extremely low pesticide movement rate and so is unlikely to be transported out of the system

It has a relatively long half-life and so persists in environment

It has a low water solubility so will not be washed away

It has a relatively high log10(sorption coefficient)/ sorption coefficient so binds to soil.

Dicamba salt since it has a much higher water solubility than DDT. Any two of: soil type, soil temperature, soil moisture content, amount of sunlight, microbial populations. GUS = log10(14) x [4 – 0.301] = 1.146 x 3.699 =4.24 (1) Higher than 4 therefore very high mobility. B

Unit must also be recorded to be awarded 2 marks In each case the significance of the data must be given to obtain the mark. Candidate must give the name of pesticide and correct reason to obtain the mark.

Accept 4.2390/.2391 mark given for value only

2

3

1

2

1

1

11 (a) A chelating agent can form more than one (coordinate) bond with a metal. ethylenediamine can form two such bonds. (1)

Alternative: a compound that can coordinate to more than one coordination position/site. (1) Ethylenediamine can coordinate to two metal positions/sites. (1)

2

(b) Both have coordination number of 6. (1) It must be clear that the candidate realises that both complexes have same coordination number of 6.

1

(c) (i) (ii)

pH = -log10[H+] [H+] = 1.58 x 10-5

Alternative: negative log to base 10 of hydrogen ion concentration. Also accept 1.6 x 10-5 Do not accept 1.5 x 10-5

1

1

TOTAL SECTION B 65


Appendix: Q9 iron calibration graph

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.5 1 1.5 2 2.5 3 3.5 4

Ab

sorb

ance

conc iron (ppm)

Iron calibration graph


Unit 4 Assessment Grids


WJEC Level 3 Diploma / Extended Diploma in Environmental Science Unit 4 Scientific principles and the environment External Assessment: documentation

Year specimen

Examiner

Reviser

Specification link SECTION A (pre-release section)

LO Unit link

AC 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.3 2.4 2.5 2.6 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.3 4.4 1 2 3

Question

1 a 3

b 3

2 a i 2

ii 1

iii 1

iv 2 1

v 2

b i 1 1

ii 1 1

3 a i 1

ii 3

4 2

Total 2 8 6 2 6 1 25

Allowed range for Section A 22-25


SECTION B

LO 1 2 3 4 Unit link

AC 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.3 2.4 2.5 2.6 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.3 4.4

1 2 3

Question

5 a i 1 1

ii 1 1

iii 2

b i 1

ii 3

6 a 7

b i 2

ii 3

iii 2

7 a i 3

ii 3

iii 3

iv 2

b 3

8 a 2

b 5

9 1 3 1

10 a i 1 1

ii 3

b 1

c 2

d 1

e 1

11 a 2

b 1

c i 1

ii 1

Section B 11 3 2 5 1 3 8 2 4 2 7 2 14 1

Section A 2 8 6 2 6 1

Total 21 22 21 26 90

Allowed range

18-23 18-23 18-23 23-29 90


WJEC Level 3 Diploma / Extended Diploma in Environmental Science Unit 4 Scientific principles and the environment Coverage

Specimen 2016 2017 2018

All AC covered in last three

years?

2019 2020 2021

All AC covered in last three

years?

2022

Section A marks in range 22-25 marks

25

LO1 marks in range 18-23 21




Synoptic links to units 1, 2 & 3

Minimum of two extended questions (>5 marks)

Principal Examiner

Reviser


WJEC Level 3 Diploma / Extended Diploma Environmental Science Unit 4 Scientific principles and the environment Assessment criteria: annual coverage

LO 1 2 3 4 Verified

AC 1.1 1.2 1.3 1.4 1.5 2.1 2.2 2.3 2.4 2.5 2.6 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 4.1 4.2 4.3 4.4

Princip

al

Exam

iner

Revis

er

YEAR

SPECIMEN 11 3 2 5 1 2 3 8 8 2 4 2 7 6 4 20 2

2016

2017

2018

2019

2020

2021

2022

WJEC Level 3 Diploma in ENVIRONMENTAL SCIENCE€¦ · Level 3 Diploma in Environmental Science 4...

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