Topic 3 States of matter separating and purifying

Question 1

1 What are the three states of matter?

Answer 1

solid, liquid, gas

Question 2

2 In which state are the particles arranged regularly?

Answer 2

solid

Question 3

3 In which state do particles move quickly in all directions?

Answer 3

gas

Question 4

4 What state change happens when a substance melts?

Answer 4

solid to liquid

Question 5

5 What state change happens when a substance condenses?

Answer 5

gas to liquid

Question 6

6 In general, which state of matter has particles with the highest energy?

Answer 6

gas

Question 7

7 What is the melting point of water in °C?

Answer 7

0 ^oC

Question 8

8 What is the boiling point of water in °C?

Answer 8

100 ^oC

Question 9

9 When a substance is melted, is energy transferred to or from the surroundings?

Answer 9

from (The substance gains energy from the surroundsing)

Question 10

10 The melting point of sodium is 97.7 °C. What is the state of sodium at 25.0 °C?

Answer 10

solid (The temperature is below the melting point, so it hasnt yet melted!)

Question 11

11 Gold is a pure substance. T or F?

Answer 11

true (although you can get alloys of gold which are mixtures and not pure substances)

Question 12

12 Air is a mixture. T or F?

Answer 12

true (it is mixture mostly of the elements Nitrogen (N₂) and Oxygen (O₂))

Question 13

13 Carbon dioxide is a mixture. T or F?

Answer 13

false (it is a compound of carbon and oxygen)

Question 14

14 Pure substances only have one type of atom present T or F?

Answer 14

false (you can get pure compounds e.g. you can get pure salt, NaCl)

Question 15

15 All mixtures are made up of compounds. T or F?

Answer 15

false (you can get a mixture of elements, for example air)

Question 16

16 Pure substances have a sharp melting temperature. T or F?

Answer 16

true (as opposed to mixtures which melt over a temperature range)

Question 17

17 A metal alloy is likely to melt over a range of temperatures. T or F?

Answer 17

true (because it is a mixture)

Question 18

18 The temperature changes as a pure substance melts. T or F?

Answer 18

false (the temperatue stays constant as the energy is used to change state (break bonds))

Question 19

19 When a substance melts, its particles move around and become less ordered. T or F?

Answer 19

true

Question 20

20 A heating curve with an upward sloping gradient during melting indicates a pure substance is present. T or F?

Answer 20

false (for a pure substance the heating curve is flat during a state change)

Question 21

21 What is a mixture?

Answer 21

different elements and/or compounds that are not chemically joined together

Question 22

22 Which is a mixture, air or water or both?

Answer 22

air (as long as the water is pure water)

Question 23

23 Which of a ‘mixture’ or a ‘pure substance’ has a fixed composition?

Answer 23

pure substance

Question 24

24 Name a pure substance.

Answer 24

any suitable e.g. gold, salt, water can all be pure

Question 25

25 Why can’t a pure substance be separated into other substances using physical means?

Answer 25

it has the same fixed composition in all of its parts

Question 26

26 Is melting a physical process or a chemical process?

Answer 26

physical

Question 27

27 Is a material that melts over a range of temperatures likely to be a mixture or a pure substance?

Answer 27

mixture

Question 28

28 Give one safety precaution to take when heating substances.

Answer 28

any suitable, tie hair back, tuck tie in, wear safety specs

Question 29

29 What do we call the change of state from a liquid to a gas?

Answer 29

evaporation

Question 30

30 Name a mixture that could be separated by filtration?

Answer 30

any suitable e.g. sand and water

Question 31

31 What is a pure substance?

Answer 31

any from: cannot be separated by physical means; same composition throughout; same properties throughout; constant chemical composition

Question 32

32 What is the difference between a mixture and a compound?

Answer 32

in a compound, different elements are joined chemically

Question 33

33 Is salty water a mixture or a compound?

Answer 33

mixture; strictly, a mixture of two compounds, water and salt

Question 34

34 How can you separate sand mixed with salty water?

Answer 34

filtration

Question 35

35 Why can’t you use filtration to get the salt from salty water?

Answer 35

salt has dissolved; pieces are too small

Question 36

36 How can you get salt from salty water?

Answer 36

evaporate the water; crystallisation

Question 37

37 What is the scientific name for a mixture like salty water?

Answer 37

solution

Question 38

38 What is the term used for the liquid in a solution?

Answer 38

solvent

Question 39

39 What is the term for the substance that has dissolved in the solution?

Answer 39

solute

Question 40

40 How can you identify a pure substance on a chromatogram?

Answer 40

only one spot/colour

Question 41

41 What are the three states of matter?

Answer 41

solid, liquid, gas

Question 42

42 What word describes a solid that dissolves in a liquid?

Answer 42

solute or soluble

Question 43

43 What name is given to a liquid that will dissolve a particular solid?

Answer 43

solvent

Question 44

44 What is the boiling point of water?

Answer 44

100 °C

Question 45

45 How can we separate an insoluble solid from a liquid?

Answer 45

filtration

Question 46

46 What word describes the clear liquid that comes through the filter paper?

Answer 46

filtrate

Question 47

47 Is mineral water pure or impure?

Answer 47

impure (it contains dissolved salts)

Question 48

48 What process takes place when a liquid turns into a gas?

Answer 48

evaporation

Question 49

49 What process takes place when a gas turns into a liquid?

Answer 49

condensation

Question 50

50 What process takes place when a liquid is changing from a liquid to a gas throughout its volume (not just at its surface)?

Answer 50

boiling (evaporation is the surface process)

Question 51

51 Which of these, if any, is pure water? Mineral water, tap water, seawater.

Answer 51

none of them (distilled water is pure water all of these contian dissolved salts (ions))

Question 52

52 Give an everyday use of tap water.

Answer 52

drinking/cooking/washing/cleaning/flushing toilets

Question 53

53 Which of these is soluble in water – sand or salt?

Answer 53

salt

Question 54

54 What separation method is used to remove insoluble solids from a liquid?

Answer 54

filtration

Question 55

55 What is the boiling point of water in degrees Celsius?

Answer 55

100 ^oC

Question 56

56 What separation method could you use to separate water from ink?

Answer 56

distillation/simple distillation

Question 57

57 Name the two state changes involved in distillation.

Answer 57

boiling/evaporating and condensing

Question 58

58 Why does sand sink to the bottom of a bucket of water?

Answer 58

it is denser than water/does not dissolve

Question 59

59 What gas with a sharp smell is used to kill bacteria in swimming pool water?

Answer 59

chlorine

Question 60

60 Why does seawater taste salty?

Answer 60

it contains dissolved salt