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Section A : Multiple Choice Questions [30 marks] Answer all questions in this section in the Optical Answer Sheet provided. 1

Based on the particle theory of matter, ________________ would not be possible. A a solid changing to gas without an intermediate liquid state B a liquid changing to solid upon being heated C a gas being compressed into a very small volume D both liquids and gas taking the shape of the container

2

An atom of gold in the liquid state is ___________ an atom of gold in the solid state. A double the size of B slightly smaller than C the same size as D half the size of

3 Which one of the following facts provides the best evidence that matter may exist as tiny particles which can move at random? A A drop of oil forms a very thin layer on the surface of water. B Most metals will conduct electricity. C A quantity of air can be compressed into a much smaller volume. D People in an enclosed space soon notice when medicated oil is being used.

4 What happens to a piece of matter when the space between its particles is increased? A Its volume is changed. B Its shape is changed. C Its volume and shape are changed. D Its volume and shape remain unchanged.

4

5

Which of the following represents a mixture of an element and a compound?

A

B

C

D

6 Which of the following is made up of only one kind of atom? A A crystal of sugar. B A piece of aluminium foil. C A drop of pure water. D A speck of dust.

7 Methane gas can be represented by the chemical formula CH4. This means it contains _______________. A five elements of two different atoms B five atoms of two different elements C four atoms of two elements D four atoms of one element

8 The molecules of water present in ice, liquid water and steam ________________. A are different in size B contain different number of atoms C contain different types of atoms D differ in the amount of energy present

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9 The atom shown below is neutral. How many protons are there in this atom? A 1 B 2 C 3 D 4

10 Study the diagram below. What is the process that has taken place? A Boiling B Condensation C Freezing D Melting

11 Which statement about a chemical change is true? A A new substance is always formed. B Heat and light are always produced. C The substance always changes state. D There is always a colour change.

Y

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12 Mixing can produce both chemical or physical (non-chemical) changes. Which of the following is correct? Chemical change Physical change A Mixing common salt in water Mixing fruit salts and water B Mixing gases in the air Mixing vinegar and chalk dust C Mixing orange juice and lemonade Mixing air in water D Mixing vinegar and an alkali Mixing sugar in tea

13 When sugar in a crucible is heated, it produces carbon and water vapour. This is an example of ___________. A combustion B decomposition C melting D respiration

14 In which of these substances could passing electricity through cause a chemical change to occur? A Copper metal B Copper sulphate solution C Crude oil (petroleum) D Salt crystals

15 In which of these chemical reactions is oxygen one of the reactants? A Decomposing limestone by heating it to form lime. B Photosynthesis in plants. C Combustion of a fuel like petrol. D Neutralisation of an acid and an alkali.

16 Which one of the differences between inhaled air and exhaled air is incorrect? Inhaled air Exhaled air A contains more oxygen contains less oxygen B contains less carbon dioxide contains more carbon dioxide C is at a higher temperature is at a lower temperature D contains less water vapour contains more water vapour

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17 Study the experimental set-up below and answer Question 17 and 18. The gas given out during the above experiment ________________. A relights a glowing splinter B turns limewater milky C turns blue litmus paper red D Is greenish-yellow in colour

18 If the position of the experimental set-up is changed from sunlight to a dark room, the rate of bubble production will most likely ____________. A increase B decrease C remain D Increase, then decrease

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The arrows shown in the diagram indicate ____________. A direction of energy flow through the organisms of a food chain B direction in which organisms move in the surroundings C order of importance of organisms in the food chain D direction of gaseous exchange between organisms in the environment

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When air is exhaled onto a mirror, the mirror appears misty. This is due to the presence of _______________ in exhaled air. A carbon dioxide B nitrogen C oxygen D water vapour

21 Gas is leaking from the kitchen. You can smell the gas because ____________. A the gas molecules move from a region of higher concentration to a region of

lower concentration by osmosis B the gas molecules move from a region of lower concentration to a region of

higher concentration by diffusion C the gas molecules move from a region of lower concentration to a region of

higher concentration by osmosis D the gas molecules move from a region of higher concentration to a region of

lower concentration by diffusion

22 Which of the following involves osmosis only? A

B

C

D

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23 Oxygen diffuses into a cell because the oxygen concentration of the cell is lower than that of its surroundings. Carbon dioxide diffuses out of the cell when the cell has a higher concentration of carbon dioxide than its surroundings. Which of the following does the cell belong to? I Green plants in the day II Green plants in the dark III Animals in the day IV Animals in the dark A I, II and III only B I, II and IV only C I, III and IV only D II, III and IV only

24 A visking tubing was filled with distilled water and was immersed in a beaker of diluted sugar solution. After some time, the visking tubing _____________. A would become enlarged B would shrink in size C would change colour D remain unchanged

25 Which is the correct order of transport of water from the soil to the leaf of a plant? A Root, root hair, phloem, leaf B Root hair, root, phloem, leaf C Root hair, root, xylem, leaf D Root, root hair, xylem, leaf

26 Plasma in the blood transports ____________. I waste substances II oxygen III carbon dioxide IV digested food A I and II only B I, II and III only C I, III and IV only D All of the above

27 The absorption of mineral salts in plants involves ___________. A active transport B diffusion C osmosis D transpiration

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28 When a rubber tapper makes a shallow cut into the bark of the rubber tree, he is ________________________. A helping to remove some of the pressure in the xylem vessels B removing some of the rubber absorbed from the ground and transported by

the xylem C helping to remove some of the pressure in the phloem vessels D removing some of the rubber produced by photosynthesis and transported by

the phloem

29 All of the following features of the human circulatory system ensures efficient distribution of oxygen and nutrients except _____________. A branching network of capillaries B thin-walled capillaries C ensuring one-way flow of blood D liquid blood

30 The clotting of blood is to ____________________. A slow down its movement inside the blood vessels B trap oxygen inside the blood so that it can be carried around more easily C seal up the wound and prevent loss of blood. D trap harmful germs inside the blood and prevent them from harming the body

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Name : ………………………………. Reg No: …….… Class : …………

Ngee Ann Secondary School Mid Year Examination 2009

Science Sec 2 Express

FOR EXAMINER’S USE ONLY

Section Marks

A

/ 30

B

/ 40

C

/ 30

TOTAL

/ 100

After checking of answer scripts

Checked by Signature Date

Student

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Section B : Structured Questions [40 marks] Answer all questions in this section in the spaces provided. 1 A substance is heated and the following graph is obtained.

(a) Write down the state(s) of matter at the following stages:

(i) before A; …………………………………………………………………..

(ii) AB ; ………………………………………………………………………..

(iii) BC ; ………………………………………………………………………..

(iv) CD ; ……………………………………………………………………….. [4]

(b)

What is the melting point and boiling point of this substance? Melting point : ………………… Boiling point : ……………………… [2]

(c) Explain why is the temperature constant at stage BC? …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………… … ……………………………………………………………………………………….[1]

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2 Complete the table below. State of matter

Solid

Motion of particles

Vibrating around a fixed position

Arrangement of particles

No regular pattern, quite strong attraction between particles

Example

[4]

3 Shown below is a neutral atom.

(i) (ii)

(a) Which part of the atom contributes to its mass? ……………………………………………………………………………………….[1]

(b) Which part of the atom helps in conducting electricity? ……………………………………………………………………………………….[1]

(c) If the mass of the atom above is 12 times the mass of a proton, how many neutrons are there in the atom? ……………………………………………………………………………………….[1]

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4 Complete the following table by filling in the spaces.

Ion structure Element Number of protons Number of electrons Charge

L

20 18

M

18 M¯

N

13 N3+

[3]

5 Identify the process involved in bringing about each of the following changes as

being chemical or physical.

(a) A block of carbon dioxide disappearing as ‘smoke’: …………………………. [1]

(b) Dew forming on leaves in the morning: ……………………………………….. [1]

(c) A matchstick being struck: ……………………………………………………….[1]

(d) A railroad track buckling under the hot sun: ……………………………………[1]

6 The table below shows the effect of gentle heating on 4 different substances.

Substance Effect of heating

Margarine Iron Chalk powder Bread

Melts No visible reaction Calcium oxide + carbon dioxide Carbon + water vapour

(a) Which substance has undergone a physical change? …………………………. ………………………………………………………….[1]

(b) Which substance(s) has a smaller mass after heating? Why? ……………………………………….. ………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………….[2]

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(c) The iron is heated to 2000C and dropped into a beaker of cold water.

State two physical changes that might occur.

(i) ………………………………………………………………………………….. ……………………………………………………………………………………

(ii) ………….……………………………………………………………………….. ………………………………………………………………………………...[2]

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Study the experimental set-up shown above. Equal amounts of air were pumped into the bell jars A, B and C respectively. This experiment is carried out in bright sunlight.

(a) In which bell jar will the candle flame extinguish fastest? Explain your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. ………………………………………………………………………………………….. ………………………………………………………………………………………….. …………………………………………………………………………………………. ……………………………………………………………………………………….[3]

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(b) In which bell jar will the candle flame burn for the longest time period? Explain your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ……………………………………………………………………………………….[3]

8 Complete the table on the components of blood.

Component of blood Function

Some engulf germs and fight infection

Red blood cells

Helps in the clotting of blood

[3]

9 The diagram below shows the results of an experiment.

(a) Where do the red ink molecules in beaker B come from? ……………………………………………………………………………………….[1]

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(b) Is this process diffusion or osmosis? Explain your answer. …………………………………………………………………………………………. ………………………………………………………………………………………….. ……………………………………………………………………………………… [2]

(c) Is the visking tubing a permeable or partially permeable membrane? Explain your choice. …………………………………………………………………………………………. ………………………………………………………………………………………….. ……………………………………………………………………………………… [2]

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Section C : Free Response Questions [30 marks] Answer ALL questions in this section in the spaces provided. 1 (a) When a candle burns, there are both chemical and non-chemical (physical)

changes. Identify one chemical and one physical change when the candle burns and explain briefly the reasons for your choice. Chemical: …………………………………………………………………………….. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………….[2] Physical: ………………………………………………………………………………. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ……………………………………………………………………………………….[2]

(b) Two sets of apparatus, P and Q, are set up as shown. The thistle funnel in

P contains sugar solution whereas that in Q contains water. The beaker in P is filled with water and that in Q is filled with concentrated sugar solution. The two set-ups are set aside for one hour.

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What will happen to the level of solution in the thistle funnels? Explain your answers. At P: ……………………………………………………………………………….. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………..[2] At Q: ………………………………………………………………………………… ………………………………………………………………………………………. ………………………………………………………………………………………. …………………………………………………………………………………….[2]

(b) The diagram below represents a molecule of the substance C2H5Cl.

(i) Is the substance an element or a compound? Explain your answer. ………………………………………………………………………………….. ………………………………………………………………………………….. ……………………………………………………………………………….[1]

(ii) How many atoms are present in each molecule of the substance? ………………………………………………………………………………..[1]

C H

ClCH

H

H H

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2 Observe the experimental set-up shown below. Jill covered a part of a leaf of a potted plant with a black piece of paper and left it in bright sunlight for a few days. Then she plucked the leaf and carried out a test to determine if starch is present.

(a) First, she placed the leaf into boiling water for two minutes. Why? ……………………………………………………………………………………….[1]

(b) Next she placed the leaf into boiling alcohol for 10 minutes. Why? ……………………………………………………………………………………….[1]

(c) She then added a few drops of iodine solution. State the colour change, if any, will be observed at parts A, B and C. Part A: …………………………………………….. Part B: …………………………………………….. Part C: …………………………………………….. [3]

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(d) Explain your answer to (c). ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………………. ……………………………………………………………………………………… [3]

(e) Write the word equation for photosynthesis. ……………………………………………………………………………………….[2]

3 (a) The diagram below shows the structure of a vascular bundle taken from

cross-section of a stem of a woody plant. Name the parts of the diagram labeled P and Q. P …………………………………. Q ………………………………… [2]

(i) Some iodine Is dropped on the surface of the stem above. Which part of the vascular bundle will be stained dark blue? ……………………………………………………………………………….. [1]

(ii) Explain briefly your answer in part (i). …………………………………………………………………………………… …………………………………………………………………………………… ………………………………………………………………………………...[1]

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(b) Below is a simple diagram to show how blood flows around your body. Label on the diagram the following:

(i) left hand side of the heart (ii) two arteries (iii) two veins (iv) the lungs [4]

(c) Mexico City is at an altitude of 2 500 metres. People who live there have more

red blood cells than other people who live at lower altitudes. Give a reason for this difference. …………………………………………………………………………………………. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ………………………………………………………………………………………….. ……………………………………………………………………………………….[2]

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