Unit 2 - WELCOME STUDENTS

Post on 16-Mar-2022

1 views 0 download

Transcript of Unit 2 - WELCOME STUDENTS

UNIT 2:

C L A S S I F I C AT I O N O F M AT T E R

MATTER

Reflect:

What is matter?

MATTER

Matter: Anything that

has mass and occupies

space.

You can describe matter in

terms of quantity by mass

NOT weight.

MATTERIn chemistry we will look at 3 different categories or phases of matter. Each

phase can be described and classified by using a PARTICLE MODEL.

Solid Liquid Gas

PROPERTIES OF MATTER

Particle Diagram

of a solid

= solid particle

Solid

Definite shape &

volume

PROPERTIES OF MATTER

Liquid

Definite volume, but

takes the shape of

its container

Particle Diagram

of a liquid

= liquid particle

PROPERTIES OF MATTER

Gas

Takes shape of

container. No

definite shape or

volume

Particle Diagram

of a gas

= gas particle

KINETIC MOLECULAR THEORY OF MATTER

• Atoms & molecules are constantly in motion

(kinetic energy) in any phase.

• We measure the average kinetic energy of these

movements of the molecules/atoms as

temperature!

• Avg. KE = Temp.

3 PHASES OF MATTER & KMT

Kinetic Molecular Theory

Solids

- Particles do move

(vibrate)

- Held tightly together

- Particles are ordered

- Least amount of energy

3 PHASES OF MATTER & KMT

Kinetic Molecular Theory

Liquids

- Some particle movement

- Still highly attracted to

each other

- Particles are disordered

- Moderate amount of energy

3 PHASES OF MATTER & KMT

Kinetic Molecular Theory

Gases:

- Lots of particle

movement

- Large distances

between the particles

- Particles are disordered

- Most amount of K.E.

HOW DO YOU CHANGE BETWEEN THE PHASES?

Big Idea:

You can change between the 3 phases of matter

by either putting energy IN or taking energy

OUT.

Increase in Temp. Causes atoms/molecules to gain more energy

(KE) and move faster

Sublimation

Fusion/Melting

Freezing

solidification

crystallization

Condensation

Vaporizing/evap

Deposition

Melting/Fusion

Freezing

Evap

Condensation

http://www.kentchemistry.com/links/Matter/HeatingCurve.htm

Big Idea: Temperature MEASURES the average kinetic energy of

particles in a sample of matter.

1. Convert 50 K to the Celsius scale.

2. Normal body temperature is 310 K. Convert this to the Celsius scale.

3. Antifreeze, or ethylene glycol, boils at 199 °C. Convert to the Kelvin scale.

Converting between Kelvin and Celsius:

Key Points on the temperature scales!

REAL GASES VS. IDEAL GASES

L I F E V S . I D E A

KINETIC MOLECULAR THEORY OF GASES: HOW CHANGES IN TEMPERATURE AFFECT VOLUME AND PRESSURE OF A GAS.

Demo Observable

Characteristic

of the Gas

Explain in terms of

particles.

Measuring

a Balloon

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic

of the Gas

Explain in terms of

particles.

Measuring

a Balloon

Gases have mass. Each particle has a mass

(total mass of the

sample is equal to the

sum of the masses of

the particles.

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic of

the Gas

Explain in terms of

particles.

Vapor

Ramp

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic of

the Gas

Explain in terms of

particles.

Vapor

Ramp

Gases have specific

densities.

The compactness of the

particles differs from gas

to gas.

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic

of the Gas

Explain in terms of

particles.

Compression(syringe)

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic

of the Gas

Explain in terms of

particles.

Compression(syringe)

Gases are

compressible

The space between

particles can be

reduced.

REA

L G

ASE

S

GASES & KMTDemo Observable

Characteristic of

the Gas

Explain in terms of

particles.

White

Smoke

(perfume)

REA

L G

ASE

S

GASES & KMT

Demo Observable

Characteristic of

the Gas

Explain in terms of

particles.

White

Smoke

(perfume)

Gases diffuse Because motion is

random, given enough

time particles will

spread out

evenly/randomly in the

given space.

REA

L G

ASE

S

When a ‘smelly gas’ such as a deodorant is let loose in a room, its particles mix

with the particles of air. The particles of ‘smelly gas’ are free to move quickly in all

directions. They eventually spread through the whole room. This is diffusion.

Diffusion in gases is quick because the particles in a gas move quickly. It happens

even faster in hot gases

GASES & KMT

Demo Observable

Characteristic of

the Gas

Explain in terms of

particles.

Ethanol

Canon(potato gun)

REA

L G

ASE

S

GASES & KMTDemo Observable

Characteristic of

the Gas

Explain in terms of

particles.

Ethanol

Canon

(potato gun)

Gases exert pressure.

This pressure exists

as a force.

Particles collide more

(create pressure) in

smaller spaces or when

they are moving faster.

REA

L G

ASE

S

Big Idea

Pressure:

Pressure is created when atoms/molecules

collide with other particles or the walls of

their container.

KMT & IDEAL GASES

THEORETICAL CHARACTERISTICS OF AN IDEAL GAS

Gases:

Postulate #1

Gas particles travel in

straight lines.

IDEA

L G

ASE

S

THEORETICAL CHARACTERISTICS OF AN IDEAL GAS

Gases:

Postulate #2

Particles collide with the walls of the

container & each other with elastic collisions.

Elastic collisions = Complete transfer of

energy.

IDEA

L G

ASE

S

INELASTIC VS. ELASTIC COLLISIONS

There are no bonds between the particles in a gas, so they are free to move

in any direction. They strike the walls of their container and create a

pressure.

THEORETICAL CHARACTERISTICS OF AN IDEAL GAS

Gases:

Postulate #3

Particles have no volume themselves.

(Exist as points)

IDEA

L G

ASE

S

THEORETICAL CHARACTERISTICS OF AN IDEAL GAS

Gases: IDEA

L G

ASE

S

Postulate #4

There are no attractive

forces between

molecules

Big Idea

Real gases act most ideal at HIGH

temperatures and LOW pressure.

KMT

Practice Regents Questions

PRESSURE & VOLUME

Boyle’s Law:

TEMPERATURE & VOLUME

Charles’ Law:

TEMPERATURE & PRESSURE

Gay – Lussac/Amonton:

GAS LAWS

Combined Gas Law:

P1V1 = P2V2

T1 T2

(temperature must be in Kelvin)

GAS LAWS Practice Problem 1: A gas at 608mm Hg is held in

a container with a volume of 545 cm3. The volume of

the container is increased to 1065 cm3 without a

change in temperature. Calculate the new pressure of

the gas.

GAS LAWS

Practice Problem 2: What will be the volume of a gas

sample at 335 K if its volume at 273 K is 8.57 L?

Assume pressure remains unchanged.

GAS LAWS Practice Problem 3: A sample of oxygen gas has a

volume of 205 cm3 when its temperature is 22.0 °C

and its pressure is 30.8 kPa. What volume will the gas

occupy at STP? (Hint: Table A)

GAS LAWS

Avogadro’s Law:

Gases with the same

Volume (at the same

temperature and

pressure) have the same

number of particles.

GAS LAWS

Practice Regents Questions.

PLEASE CREATE AN ACCOUNT

• Go to testwizard.com

• Create an account using your gmail account

• Please join the class using the following code: CCOS-2CIM-XV

PLEASE GO TO GOOGLE CLASSROOM

• Complete the assignment U1V4 Classification of Matter

• RESULTS WILL BE SUBMITTED AND SENT IN FOR A GRADE!!

PURE SUBSTANCE: ONE TYPE OF

PARTICLE.

Definition: Made of 1 type of atom

Representation:

Characteristics:

- Cannot be broken down/separated (chemically)

- Pure Substances (contains only 1 type of particle)

- Written w/ symbols

- 92 natural, aprox 118 total (named after people, places, Latin names, etc)

- Ex: Copper, Calcium, Hydrogen, O2, Mg, Cu, F2

Elements

COMPOUNDSDefinition: Made up of 2 or more elements chemically combined.

(bonded together)

Representation:

Characteristics:

- Chemically bonded (can be chemically separated)

- Pure substance

- Have different properties than the elements that make them up

- Specific ratio of elements within the compound

- Written with formulas

Examples: Copper (II) Chloride, Sodium Chloride, H2O, C6H12O6

CLASSIFICATION OF MATTERParticle Diagram Practice: Label the boxes below

as an element, mixture or compound.

CLASSIFICATION OF MATTER

Reflect:

If solid water melts into liquid water, has the basic identity of the water changed? Explain.

No, it is still water, it is just in a different phase.

If water is decomposed into oxygen and hydrogen gas, has the basic identity of the water changed? Explain.

Yes, it is no longer 2 hydrogens and an oxygen bonded together. The molecule has been separated into two distinct different elements.

Big Idea

Regardless if matter is going through a physical change or a

chemical change, the amount of matter ALWAYS STAYS

CONSTANT.

Amount of matter before the change = Amount of matter

after the change

Law of Conservation of Matter:

Matter (mass) can not be created or destroyed, it just changes form.

Complete the Practice Regents Questions

SEPARATING MIXTURES BASED ON THEIR COMPOSITION:SEPARATION OF HETEROGENEOUS MIXTURESFiltration

• Based on differences in phase

• Works on separating particles

that do NOT dissolve.

• Ex: separating sand and water

mixture

Magnetism

• Based on magnetic/ metallic

properties

Ex: separating iron filings from a

nonmetallic substance (sulfur).

SEPARATING MIXTURES BASED ON THEIR COMPOSITION:SEPARATION OF HOMOGENEOUS MIXTURES

Distillation

• Based on differences in boiling

points

• Separates liquids from each

other. Liquid w/ the lower boiling

point boils off first.

Ex: separating

crude oil

Chromatography

• Based on differences in solubility

& polarity

Ex: separating plant pigments or

ink

SEPARATING MIXTURES BASED ON THEIR COMPOSITION:SEPARATION OF HOMOGENEOUS MIXTURES

Evaporation/Crystallization:

• For use in separating solids dissolved in a liquid.

Ex: aqueous salt solution (separating the salt from salt

water).

KINETIC MOLECULAR THEORY

Kinetic Molecular Theory: The theory of the

movement of molecules at different pressures

and temperatures.

GASES & KMT

Temperature:

Total average kinetic energy of

particles

Pressure:

Sum of collisions between

particles/walls of container

GAS LAWS II

Reflect: Explain, in terms of kinetic molecular theory, why the pressure increases in a gas sample if you increase temperature (assume the volume remains constant)

GAS LAWS IIGraham’s Law: The lighter a gas is, the quicker it

diffuses (or effuses – goes through a small hole).

Which gas would diffuse (or

effuse) fastest?

CH4

CO2

He

H2

GAS LAWS II

Dalton’s Law of Partial Pressures:

The total pressure of a gas is equal to the sum of

the partial pressures of the individual gases that

make up the sample. Pt = Pa + Pb + Pc….

GAS LAWS II

Practice Problem 1: What is the atmospheric

pressure if the partial pressure of nitrogen,

oxygen and argon are 604.5 mm Hg, 162.8 mm

Hg, and 0.5 mm Hg, respectively?

GAS LAWS IIPractice Problem 2: If the total pressure of a gas

sample is 33.9 atm, what is the partial pressure

of an unknown gas if the other gases have partial

pressures as follows: oxygen gas is 10.4 atm,

hydrogen 7.8, and carbon dioxide is 4.2 atm?

CLASSIFICATION OF MATTER

Reflect:

State the term for as many phase changes as you can.

CLASSIFICATION OF MATTER

PURE SUBSTANCE: ONE TYPE OF

PARTICLE.

Definition: Made of 1 type of atom

Representation:

Characteristics:

- Cannot be broken down/separated (chemically)

- Pure Substances

- Written w/ symbols

- 92 natural, aprox 118 total (named after people, places, Latin names, etc)

- Ex: Copper, Calcium, Hydrogen, O2, Mg, Cu, F2

Elements

COMPOUNDSDefinition: Made up of 2 or more elements chemically combined.

(bonded together)

Representation:

Characteristics:

- Chemically bonded (can be chemically separated)

- Pure substance

- Have different properties than the elements that make them up

- Specific ratio of atoms

- Written with formulas

Examples: Copper (II) Chloride, Sodium Chloride, H2O, C6H12O6

CLASSIFICATION OF MATTERParticle Diagram Practice: Label the boxes below

as an element, mixture or compound.

Answer Practice Regents Questions