Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

LTS KS3 Science > C3 Pure and Impure Substances > Flashcards

C3 Pure and Impure Substances Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Define element

A

A substance made of only one type of atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define (chemical) compound

A

Substance made of more than one type of atom chemically bonded together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define (chemical) molecule

A

Two or more atoms, chemically bonded into a single particle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Does a molecule have to be a compound?

A

No, a molecule can be an element made of more than one of the same type of atom chemically bonded together into a single particle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define (chemically) pure

A

When a substance is made of only one element or compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define (chemically) impure

A

When a substance is made of more than one element or compound, or a mixture of elements and compounds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a mixture?

A

An impure substance that can be separated by physical (not chemical) processes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is spring water pure? Explain your answer.

A

No. Spring water contains minerals, as well as water molecules which are not chemically bonded.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Is air pure? Explain your answer.

A

No. Air contains a mixture of elements and compounds in their gaseous state which are not chemically bonded.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

State one similarity and one difference between boiling and evaporation?

A

Similarity: both a state change from liquid to gas
Difference: Evaporation can occur at any temperature, boiling occurs at the boiling point of the substance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define dissolve

A

When a substance is added to a solvent (liquid) and its particles spread out evenly within the liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define solute

A

A solid or gas that dissolves in a solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define solvent

A

A liquid that dissolves a solute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define solution

A

A mixture made when a solute dissolves in a solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define solubility

A

The mass of a solute that will dissolve in a given volume of solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define insoluble

A

A substance that does not dissolve in a liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define soluble

A

A substance that does dissolve in a liquid (solvent).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a saturated solution?

A

A solution where no more solute will dissolve in the solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Generally, what is the effect of increasing the temperature on solubility?

A

The greater the temperature, the greater the solubility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What piece of equipment could be used to separate marbles from sand, and what physical property does it separate them based on?

A

Sieve. Based on the size of the object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What physical property does filtration separate substances based on?

A

Size of particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What word could be used to describe the solubility of sand in water?

A

Insoluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the name of the substance left in the filter (paper) after filtration?

A

Residue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the name of the substance that passes through the filter (paper)?

A

Filtrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What types of substances are most commonly separated by filtration in chemistry?

A

Insoluble solids from liquids

26
Q

What types of substances are most commonly separated by evaporation in chemistry?

A

Soluble solids from liquids

27
Q

What is crystallisation?

A

Slow evaporation that allows crystals to form.

28
Q

What physical property does chromatography separate substances based on?

A

Solubility

29
Q

What is chromatography used to separate?

A

Pigments (colours) in a solution.

30
Q

Which part of the simple chromatography set-up is considered the stationary phase?

A

The paper.

31
Q

Which part of the set-up above is considered the mobile phase?

A

The solution moving up the paper.

32
Q

What formula can be used to calculate the retention factor (Rf) of the pigment?

A

Rf = Distance moved by pigment / Distance moved by solvent

33
Q

Calculate the Rf value of red pigment which has moved 2cm when the solvent has moved 10cm on a chromatogram.

A

Rf= 2/10 = 0.2

34
Q

Calculate the Rf value of the purple pigment which has moved 6cm when the solvent has moved 10cm on a chromatogram.

A

Rf= 6/10 = 0.6

35
Q

What is the piece of paper with separated pigments called, once chromatography is complete?

A

Chromatogram

36
Q

What process can be used to separate two liquids based on their boiling points?`

A

Distillation

37
Q

What is the state change that occurs in the round bottomed flask during simple distillation?

A

Boiling or evaporation (liquid to gas)

38
Q

What is the state change that occurs in the condenser during simple distillation?

A

Condensing (gas to liquid)

39
Q

What does desalination mean?

A

To remove salt from salt water (sea water)

40
Q

Why do we not use desalination to produce drinking water in the UK?

A

Very energy intensive. No need as we have a good supply of clean drinking water.

41
Q

Fractional distillation separates out a range of different chemicals based on their…

A

Boiling points.

42
Q

Give two mixtures that are commonly separated using fractional distillation.

A

Air and crude oil

43
Q

What scale is used to represent how acidic or alkaline something is?

A

pH scale

44
Q

What is the pH of a neutral substance?

A

7

45
Q

What is the pH of an acidic substance?

A

Less than 7

46
Q

What is the pH of an alkali substance?

A

More than 7

47
Q

How could you describe a substance of pH 8

A

(Weak) Alkali

48
Q

How could you describe a substance of pH 2

A

(Strong) Acid

49
Q

How could you describe a substance of pH 5

A

(Weak) Acid

50
Q

How could you describe a substance of pH 14

A

(Strong) Alkali

51
Q

What is the standard word equation for a reaction between an acid and an alkali?

A

Acid + Alkali → Salt + Water

52
Q

What type of salts are formed by hydrochloric acid?

A

Chloride salts

53
Q

What type of salts are formed by sulfuric acid?

A

Sulfate salts

54
Q

What type of salts are formed by nitric acid?

A

Nitrate salts

55
Q

Give the word equation for the reaction between copper oxide and sulphuric acid

A

Copper oxide + sulfuric acid → copper sulphate + water

56
Q

Give the word equation for the reaction between sodium hydroxide and hydrochloric acid

A

sodium hydroxide + hydrochloric acid → sodium chloride + water

57
Q

Give the word equation for the reaction between potassium hydroxide and nitric acid

A

potassium hydroxide + nitric acid → potassium nitrate + water

58
Q

What is the name for a reaction where the pH moves towards 7.

A

Neutralisation

59
Q

What colour of universal indicator is usually associated with acidic substances.

A

Red

60
Q

What colour of universal indicator is usually associated with alkaline substances.

A

Purple / Blue

61
Q

What colour of universal indicator is usually associated with neutral substances.

A

Green

LTS KS3 Science (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions