Topic 3 States of matter separating and purifying Flashcards Preview

Edexcel GCSE Combined Science (Chemistry) 2022 > Topic 3 States of matter separating and purifying > Flashcards

Flashcards in Topic 3 States of matter separating and purifying Deck (60)
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1
Q

1 What are the three states of matter?

A

solid, liquid, gas

2
Q

2 In which state are the particles arranged regularly?

A

solid

3
Q

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

A

gas

4
Q

4 What state change happens when a substance melts?

A

solid to liquid

5
Q

5 What state change happens when a substance condenses?

A

gas to liquid

6
Q

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

A

gas

7
Q

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

A

0 oC

8
Q

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

A

100 oC

9
Q

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

A

from (The substance gains energy from the surroundsing)

10
Q

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

A

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

11
Q

11 Gold is a pure substance. T or F?

A

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

12
Q

12 Air is a mixture. T or F?

A

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

13
Q

13 Carbon dioxide is a mixture. T or F?

A

false (it is a compound of carbon and oxygen)

14
Q

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

A

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

15
Q

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

A

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

16
Q

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

A

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

17
Q

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

A

true (because it is a mixture)

18
Q

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

A

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

19
Q

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

A

true

20
Q

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

A

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

21
Q

21 What is a mixture?

A

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

22
Q

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

A

air (as long as the water is pure water)

23
Q

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

A

pure substance

24
Q

24 Name a pure substance.

A

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

25
Q

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

A

it has the same fixed composition in all of its parts

26
Q

26 Is melting a physical process or a chemical process?

A

physical

27
Q

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

A

mixture

28
Q

28 Give one safety precaution to take when heating substances.

A

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

29
Q

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

A

evaporation

30
Q

30 Name a mixture that could be separated by filtration?

A

any suitable e.g. sand and water

31
Q

31 What is a pure substance?

A

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

32
Q

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

A

in a compound, different elements are joined chemically

33
Q

33 Is salty water a mixture or a compound?

A

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

34
Q

34 How can you separate sand mixed with salty water?

A

filtration

35
Q

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

A

salt has dissolved; pieces are too small

36
Q

36 How can you get salt from salty water?

A

evaporate the water; crystallisation

37
Q

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

A

solution

38
Q

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

A

solvent

39
Q

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

A

solute

40
Q

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

A

only one spot/colour

41
Q

41 What are the three states of matter?

A

solid, liquid, gas

42
Q

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

A

solute or soluble

43
Q

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

A

solvent

44
Q

44 What is the boiling point of water?

A

100 °C

45
Q

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

A

filtration

46
Q

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

A

filtrate

47
Q

47 Is mineral water pure or impure?

A

impure (it contains dissolved salts)

48
Q

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

A

evaporation

49
Q

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

A

condensation

50
Q

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

A

boiling (evaporation is the surface process)

51
Q

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

A

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

52
Q

52 Give an everyday use of tap water.

A

drinking/cooking/washing/cleaning/flushing toilets

53
Q

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

A

salt

54
Q

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

A

filtration

55
Q

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

A

100 oC

56
Q

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

A

distillation/simple distillation

57
Q

57 Name the two state changes involved in distillation.

A

boiling/evaporating and condensing

58
Q

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

A

it is denser than water/does not dissolve

59
Q

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

A

chlorine

60
Q

60 Why does seawater taste salty?

A

it contains dissolved salt