STATES OF MATTER AND ECM

Question 1

What is the interconversion called when water vapor changes into liquid water?

Answer 1

Condensation

Question 2

Describe what happens when water vapor cools to form liquid water in terms, (Change in energy, arrangement and movement of particles).

Answer 2

Change in energy: The particles lose kinetic energy

Arrangement: The particles move closer

Movement of particles: The particles do not move as freely

Question 3

Which state symbol is used most often for the elements of the Periodic Table at room temperature?

Answer 3

Solid

Question 4

Which term is used for a solid changing to a liquid?

Answer 4

Melting

Question 5

Describe the movement of particles in a gas.

Answer 5

The particles move in random motion

Question 6

Explain why heating a liquid causes it evaporate more quickly.

Answer 6

1. Kinetic energy of the particles increases
2. Particles overcome the forces of attraction between them

Question 7

Write an equation, including state symbols, for the change of state from steam to water.

Answer 7

H2O (g) —> H2O (l)

Question 8

Suggest why liquid in a beaker needs to be stirred constantly.

Answer 8

To keep the liquid at an even temperature

Question 9

What is the name of the interconversion that is used to separate the solution of the green coloring from the remaining grass?

Answer 9

Boiling

Question 10

Which separating technique should be used to separate calcium carbonate from a mixture of calcium carbonate and water?

Answer 10

Filtration

Question 11

Which separating technique should be used to separate CuSO4.5H2O(s) from CuSO4(aq)?

Answer 11

Crystallization

Question 12

What is the meaning of the term solvent?

Answer 12

It is the liquid the solute dissolves in

Question 13

Which separating technique should be used to separate the dilute solution of zinc nitrate from a mixture?

Answer 13

Filtration

Question 14

What is meant by the term compound?

Answer 14

Two or more elements that are chemically bonded

Question 15

Na - 2,8,1

Cl - 2,8,7

Describe the changes in the electronic configurations of sodium and chlorine when these atoms form sodium chloride.

Answer 15

Na loses 1 electron and Cl gains 1 electron to have a stable arrangement. Sodium(Na) becomes 2,8 and Chlorine (Cl) becomes 2,8,8.

Question 16

Which method of separation should be used to obtain sand from a mixture containing salt, sand, and water?

Answer 16

Filtration

Question 17

Which method of separation should be used to obtain copper(II) sulfate from a mixture containing copper (II) sulfate and water?

Answer 17

Crystallization

Question 18

Explain, in terms of particles why the white ring of NH4Cl form closest to HCl.

Answer 18

1. Ammonia diffuses at a faster rate compared to hydrochloric acid
2. Ammonia has a lower relative formula mass (RFM) - 17, compared to Hydrochloric acid - 36.5

Question 19

What factors affect Solubility?

Answer 19

1. The temperature
2. Stirring
3. Type of solvent
4. Type of solute

Question 20

What is simple distillation?

Answer 20

Used to separate a liquid and soluble solid from a solution ( water from a solution of salt water )

Question 21

What is filtration?

Answer 21

Used to separate an undissolved solid from a mixture of the solid and a liquid/solution ( Sand from a mixture of sand and water)

Question 22

Which method of separation should be used to obtain ethanol (alcohol) from a mixture of ethanol and water?

Answer 22

Fractional Distillation

Question 23

Which method of separation should be used to obtain kerosene from a mixture of crude oil?

Answer 23

Fractional distillation

Question 24

What is diffusion?

Answer 24

• Movement of particles from an area of high concentration to an area of low concentration
• For this to work, particles must be able to move

Question 25

Why does diffusion not occur in solids?

Answer 25

Diffusion does not occur in solids, since the particles cannot move from place to place (only vibrate)

Question 26

solubility of solids increases when ___________ increases

Answer 26

temperature

Question 27

solubility of ____ increases when ________ increases

Answer 27

gases, pressure

Question 28

any mass below the line for a _______ at a specific temperature would mean the solution was ________

Answer 28

solute, unsaturated

Question 29

any mass above the line for a _______ at a specific temperature would mean the solution was __________ and _______

Answer 29

solute, supersaturated, unstable

Question 30

What is a pure substance?

Answer 30

a single element or compound, not mixed with any other substance

Question 31

What is crystallization?

Answer 31

Used to separate a soluble salt from the solution it was dissolved in

Question 32

What is paper chromatography?

Answer 32

Used to separates different pigments in a coloured substance

Question 33

How to calculate the Rf value?

Answer 33

Rf value = distance moved by the substance/distance moved by the solvent

Question 34

How do we find out that there are compounds in the mixture and a pure compound on a chromatogram?

Answer 34

Compounds in a mixture may separate into different spots depending on the solvent but a pure compound will produce a single spot in all solvents

Question 35

Why should the water level be below the food dyes?

Answer 35

- To stop the dyes from mixing with water.

Question 36

Suggest why ethanol is used instead of water

Answer 36

The orange coloring dissolves in ethanol

Question 37

How would the student know when she has added an excess of zinc carbonate?

Answer 37

No more fizzing

Question 38

Why are alloys harder than pure metals?

Answer 38

This is because: - There are different sizes of atoms - that disrupts the regular arrangement - making it more difficult for them to slide over each other.