Topic 3 States of matter separating and purifying Flashcards by Oliver Bennett

1 What are the three states of matter?

solid, liquid, gas

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2 In which state are the particles arranged regularly?

solid

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

gas

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4 What state change happens when a substance melts?

solid to liquid

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5 What state change happens when a substance condenses?

gas to liquid

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

gas

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

0 ^oC

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

100 ^oC

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

from (The substance gains energy from the surroundsing)

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

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

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11 Gold is a pure substance. T or F?

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

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12 Air is a mixture. T or F?

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

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13 Carbon dioxide is a mixture. T or F?

false (it is a compound of carbon and oxygen)

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

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

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

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

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

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

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

true (because it is a mixture)

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

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

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

true

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

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

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21 What is a mixture?

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

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

air (as long as the water is pure water)

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

pure substance

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24 Name a pure substance.

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

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

it has the same fixed composition in all of its parts

26 Is melting a physical process or a chemical process?

physical

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

mixture

28 Give one safety precaution to take when heating substances.

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

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

evaporation

30 Name a mixture that could be separated by filtration?

any suitable e.g. sand and water

31 What is a pure substance?

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

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

in a compound, different elements are joined chemically

33 Is salty water a mixture or a compound?

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

34 How can you separate sand mixed with salty water?

filtration

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

salt has dissolved; pieces are too small

36 How can you get salt from salty water?

evaporate the water; crystallisation

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

solution

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

solvent

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

solute

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

only one spot/colour

41 What are the three states of matter?

solid, liquid, gas

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

solute or soluble

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

solvent

44 What is the boiling point of water?

100 °C

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

filtration

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

filtrate

47 Is mineral water pure or impure?

impure (it contains dissolved salts)

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

evaporation

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

condensation

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

boiling (evaporation is the surface process)

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

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

52 Give an everyday use of tap water.

drinking/cooking/washing/cleaning/flushing toilets

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

salt

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

filtration

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

100 ^oC

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

distillation/simple distillation

57 Name the two state changes involved in distillation.

boiling/evaporating and condensing

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

it is denser than water/does not dissolve

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

chlorine

60 Why does seawater taste salty?

it contains dissolved salt

61 How is water made for drinking? To remove impurities.

The water needs to be dealt with the impurities in it. 1. Put into a sedimentation tank, where small particles are allowed to settle out. 2. Filtrate the water in filtration towers containing sand and gravel. 3. Chlorine is added in chlorination which kills microorganisms in the treated water. 4. Piped into people’s homes and industry. 1. Course filtration - filtered to remove twigs etc. 2. Sedimentation - a chemical is added which makes particles sink to the bottom. 3. Fine filtration - filtered through sand. 4. Chlorination - chlorine is added which kills microorganisms in the treated water. 5. Piped to people's houses after being stored in towers.

62 If the heating curve for a substance is stationary at melting and boiling points then it is a pure or mixed substance?

Pure.

63 If the heating curve for a substance is moving at melting and boiling points then it is a pure or mixed substance?

Mixed or impure substance

64 What is it called you to from a gas to a solid?

Deposition

65 What is it called when you go from a solid to a gas?

Sublimation

66 What is a solution?

A mixture made of solutes (dissolved substances) in a liquid called the solvent.

67 What does crystallisation do?

Separates the solute from a solution by evaporating the solvent to leave the solutes behind.

68 What does filtration do?

Used to separate some mixtures. They let smaller pieces or liquids through but trap bigger pieces or insoluble substances.

69 Calculate the Rf value

Rf = distance moved by the spot/distance moved by the solvent

70 What is chromatography used to separate?

Used to find out which coloured compounds the mixture contains.

71 Why do we use pencil not pen, for the starting line when separating inks and dyes in paper chromatography?

The pencil doesn’t contain a mixture like pen does so won’t move up the paper making inaccurate results.

72 What is the mobile phase?

The solvent

73 What’s the stationary phase?

The paper contains the stationary phase.

74 What is the paper with the separated components on it called?

A chromatogram

75 What are the two distillation types?

Simple Fractional

76 What does simple distillation separate?

Soluble or dissolved solids from liquids.

77 What can fractional distillation be used for?

To separate the different products in crude oil. To make alcohol dunks, such as whisky and vodka. To separate out the gases in the air, after the air has been cooled and turned into a liquid at -200°C

78 Simple distillation set up with a condenser?

79 Fractional distillation set up?

80 Filtration set up?

81 Crystallisation set up?

82 Paper Chromatography set up?

83 What is a Hazard?

What is dangerous - Bunsen Burner

84 What is a risk?

The harm a hazard could do. e.g. Hair could catch fire.

85 What is the Control measure?

How you make it safe. e.g. Tie your hair back.