Topic 3 States of matter separating and purifying Flashcards Preview

Edexcel GCSE Combined Science (Chemistry) > 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

1 What are the three states of matter?

solid, liquid, gas

2

2 In which state are the particles arranged regularly?

solid

3

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

gas

4

4 What state change happens when a substance melts?

solid to liquid

5

5 What state change happens when a substance condenses?

gas to liquid

6

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

gas

7

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

0 oC

8

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

100 oC

9

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

from   (The substance gains energy from the surroundsing)

10

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!)

11

11 Gold is a pure substance. T or F?

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

12

12 Air is a mixture. T or F?

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

13

13 Carbon dioxide is a mixture. T or F?

false (it is a compound of carbon and oxygen)

14

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)

15

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

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

16

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

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

17

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

true (because it is a mixture)

18

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))

19

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

true

20

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)

21

21 What is a mixture?

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

22

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

air (as long as the water is pure water)

23

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

pure substance

24

24 Name a pure substance.

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

25

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

26 Is melting a physical process or a chemical process?

physical

27

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

mixture

28

28 Give one safety precaution to take when heating substances.

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

29

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

evaporation

30

30 Name a mixture that could be separated by filtration?

any suitable e.g. sand and water

31

31 What is a pure substance?

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

32

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

in a compound, different elements are joined chemically

33

33 Is salty water a mixture or a compound?

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

34

34 How can you separate sand mixed with salty water?

filtration

35

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

salt has dissolved; pieces are too small

36

36 How can you get salt from salty water?

evaporate the water; crystallisation

37

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

solution

38

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

solvent

39

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

solute

40

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

only one spot/colour

41

41 What are the three states of matter?

solid, liquid, gas

42

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

solute or soluble

43

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

solvent

44

44 What is the boiling point of water?

100 °C

45

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

filtration

46

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

filtrate

47

47 Is mineral water pure or impure?

impure (it contains dissolved salts)

48

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

evaporation

49

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

condensation

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)?

boiling (evaporation is the surface process)

51

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

52 Give an everyday use of tap water.

drinking/cooking/washing/cleaning/flushing toilets

53

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

salt

54

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

filtration

55

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

100 oC

56

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

distillation/simple distillation

57

57 Name the two state changes involved in distillation.

boiling/evaporating and condensing

58

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

it is denser than water/does not dissolve

59

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

chlorine

60

60 Why does seawater taste salty?

it contains dissolved salt