Chemistry - States of Matter and Mixtures

Question 1

Describe the arrangement and motion of particles in a solid

Answer 1

Vibrate around a fixed position

Question 2

Describe the arrangement and motion of particles in a liquid

Answer 2

Move around each other randomly close together

Question 3

Describe the arrangement and motion of particles in a gas

Answer 3

Move randomly far apart

Question 4

What word describes the change of a solid into a liquid

Answer 4

melting

Question 5

What word describes the change of a liquid to a gas

Answer 5

evaporation

Question 6

What word describes the change of a gas into a liquid

Answer 6

condensation

Question 7

What word describes the change of a liquid into a solid

Answer 7

freezing

Question 8

What word describes the change of a solid into a gas

Answer 8

sublimation

Question 9

Describe what happens to the stored energy of the particles when a solid changes to a liquid

Answer 9

stored energy increases (liquid has more energy than solid)

Question 10

Describe what happens to the stored energy of the particles when a gas changes into a liquid

Answer 10

stored energy decreases (liquid has less energy than gas)

Question 11

Chlorine has a boiling point of -34^oC. Predict its state at room temperature

Answer 11

Gas (Room temperature (25^oC, is higher than the boiling point)

Question 12

Describe the difference between a pure and impure substance

Answer 12

pure substance is made of only one type of atom, has a uniform structure. Impure substance contains different types of atoms.

Question 13

Describe the difference in the melting point of a pure and impure substance

Answer 13

A pure substance has a single sharp melting point. An impure substance melts over a range.

Question 14

Explain how distillation separates a mixture of ethanol and water

Answer 14

Ethanol has a lower boiling point than water Ethanol evaporates first Then condenses in the condenser

Question 15

State the four methods of separation

Answer 15

Distillation Filtration Crystallisation Chromatography

Question 16

Which separation technique could be used to separate a mixture of sand and water

Answer 16

Filtration as sand particles can’t fit through the filter paper

Question 17

Which separation technique could be used to separate a mixture of coloured inks

Answer 17

Chromatography

Question 18

Which separation technique could be used to separate a mixture of water and ink

Answer 18

Distillation

Question 19

What is the mobile phase in chromatography

Answer 19

The solvent (water)

Question 20

What is the stationary phase in paper chromatography

Answer 20

paper

Question 21

Describe how to set up chromatography to separate the inks in a coloured pen

Answer 21

-Draw a line on a piece of chromatography in pencil -Put a dot of the pen on the pencil line -Suspend the paper in the chromatography tank so the paper just touches the water -Wait for the inks to separate -Calculate the Rf values

Question 22

What is the equation to calculate Rf value

Answer 22

Rf value = distance substance moved ÷ distance solvent moved

Question 23

What are the three stages of water treatment

Answer 23

Sedimentation, filtration, chlorination

Question 24

Describe sedimentation of water

Answer 24

Sand and grit are allowed to settle at the bottom of the tank

Question 25

Describe filtration of water

Answer 25

Insoluble solids are removed from the water

Question 26

Describe chlorination of water

Answer 26

Chlorine is added to the water to kill bacteria

Question 27

Explain how sea water is made potable using distillation

Answer 27

sea water is heated until it evaporates water condenses leaving salt behind

Question 28

Explain why distilled water must be used for analysis

Answer 28

Tap water contains dissolved salts which can give false results

Question 29

What conclusions can be made from this chromatogram

Answer 29

* S contains six / 6 colourings * P contains five / 5 colourings if neither of first 2 bullet points given allow 1 mark for S contains more colours than P or converse • both S and P contain the same five / 5 colourings * both contain W and Y * both sweets (may) cause hyperactivity ignore unsafe • neither contain X and Z

Question 30

Calculate the Rf value of W

Answer 30

3 ÷ 10 = 0.3

Question 31

Label parts A and B on the diagram

Answer 31

A - round bottomed flask B - condenser

Question 32

Does this melting point graph show a pure or impure substance

Answer 32

Pure as it has a sharp melting point (horizontal line)