Chemistry Revision Flashcards
(102 cards)
1
Q
Atom
A
A basic unit of matter that cannot be broken down by chemical reactions.
2
Q
Element
A
A pure substance made of only one type of atom.
3
Q
Mixture
A
A combination of substances that can be separated by physical means.
4
Q
Compound
A
A substance formed when two or more elements are chemically bonded.
5
Q
Atomic Number
A
The number of protons in an atom’s nucleus.
6
Q
Atomic Mass
A
The total number of protons and neutrons in an atom.
7
Q
Positive ion
A
An atom that has lost one or more electrons (usually metals).
8
Q
Negative ion
A
An atom that has gained one or more electrons (usually non-metals).
9
Q
Alloy
A
A mixture of metals.
10
Q
Solvent
A
A liquid in which a solute dissolves.
11
Q
Solute
A
The substance that dissolves in a solvent.
12
Q
Solution
A
A mixture formed when a solute dissolves in a solvent.
13
Q
Saturated solution
A
A solution where no more solute can dissolve at a given temperature.
14
Q
Demokritos
A
Ancient Greek who proposed the idea of the indivisible atom.
15
Q
John Dalton
A
Scientist who developed early atomic theory in the 1800s.
16
Q
Dalton’s atomic theory
A
All matter is made of atoms; atoms are indestructible and identical in an element.
17
Q
Proton
A
Subatomic particle with a positive charge and mass of 1.
18
Q
Neutron
A
Subatomic particle with no charge and mass of 1.
19
Q
Electron
A
Subatomic particle with a negative charge and negligible mass.
20
Q
Relative mass of proton
A
1
21
Q
Relative mass of neutron
A
1
22
Q
Relative mass of electron
A
1/1850
23
Q
Relative charge of proton
A
1
24
Q
Relative charge of neutron
A
0
25
Relative charge of electron
-1
26
Group
Vertical columns in the periodic table with similar properties.
27
Period
Horizontal rows in the periodic table.
28
Periodic table
Arrangement of elements by atomic number.
29
Group 1 elements
Alkali metals, very reactive.
30
Group 7 elements
Halogens, very reactive non-metals.
31
Group 8 elements
Noble gases, unreactive.
32
Chemical symbol
A one or two-letter abbreviation for an element.
33
Chemical formula
Tells the number and type of atoms in a compound.
34
FeS
Chemical formula for iron sulphide.
35
Na₂O
Chemical formula for sodium oxide.
36
CO₂
Chemical formula for carbon dioxide.
37
Balanced equation
Shows equal numbers of each atom on both sides.
38
Unbalanced equation
Has unequal atoms on both sides.
39
Example of balanced equation
2Cu + O₂ → 2CuO
40
Iron
Fe
41
Sulphur
S
42
Sodium
Na
43
Oxygen
O
44
Hydrogen
H
45
Chlorine
Cl
46
Carbon
C
47
Nitrogen
N
48
Helium
He
49
Neon
Ne
50
Solid
State of matter with fixed shape and volume.
51
Liquid
State of matter that flows and takes shape of container.
52
Gas
State of matter that fills the container and is easily compressed.
53
Properties of metals
Strong, shiny, conductors, high melting points, malleable.
54
Properties of non-metals
Brittle, dull, poor conductors, low melting points.
55
How does Filtering work?
If your solid does not dissolve in water, separate the solid from the liquid by filtering the suspension through filter paper.
56
How does Evaporating work?
If your mixture is a solution, heat the liquid and it will evaporate away to leave the solid.
57
How does Crystallising work
You can separate many solids contained in saturated solutions by leaving them to form crystals.
58
How does Centrifuging work.
A centrifuge is used to separate small amounts of solid held in suspension from the liquid. For example, chalk from water. The centrifuge contains test-tubes that are spun around at high speed that causes the solid to sink to the bottom of the tube. The liquid is the decanted (poured off) leaving the solid behind.
59
How does Simple distillation work
The solution is heated in the round-bottomed flask. As it boils,
steam rises into the condenser (this cools the steam back to water). Eventually the salt (solute) is left behind. The water collected in the beaker is called distilled water.
60
Fractional distillation
If two liquids are miscible (i.e. they mix together well),Since, ethanol boils at 78oC and water at 100oC, then by gradually heating the
mixture, ethanol and water vapour rises up the column making the glass beads hot as they condense on them. Once the beads are 78C, the ethanol vapour is forced into the condenser, whilst the water vapour continues to condense and drip back into the flask. Mean while the ethanol, now in the condenser, condenses and drips into the beaker as liquid ethanol.
61
Separating funnel
Used to separate immiscible liquids.
62
Paper chromatography
Separates mixtures of coloured compounds.
63
Chromatogram
The result of chromatography.
64
Most soluble component
In chromatography, moves furthest from the original spot.
65
Rf value
Distance moved by compound ÷ distance moved by solvent.
66
CO₂ test
Turns limewater cloudy.
67
H₂ test
Lit splint causes a squeaky pop.
68
O₂ test
Glowing splint relights.
69
Thermal decomposition
Breakdown of compound using heat.
70
Example of decomposition
CaCO₃ → CaO + CO₂
71
Combination reaction
Two reactants form one product.
72
Example of combination
2Na + Cl₂ → 2NaCl
73
Electrolysis
Uses electricity to break down compounds.
74
Example of electrolysis
PbBr₂ → Pb + Br₂
75
Precipitation reaction
Forms insoluble solid from two solutions.
76
Combustion
Reaction with oxygen producing oxide and releasing heat.
77
Oxidation
Gain of oxygen.
78
Reduction
Loss of oxygen.
79
Displacement reaction
More reactive element replaces less reactive one.
80
Neutralisation
Acid + base reaction forming salt and water.
81
Metal + acid → salt + H₂
E.g. Ca + 2HCl → CaCl₂ + H₂
82
Base + acid → ?
salt + water
83
Alkali + acid → ?
salt + water
84
Metal carbonate + acid → ?
salt + water + CO₂
85
Acids
Taste sour, pH < 7, turn blue litmus red.
86
Alkalis
Soapy, pH > 7, turn red litmus blue.
87
Neutral substances
pH = 7, do not affect litmus.
88
Hydrochloric acid
Forms chlorides in reactions.
89
Nitric acid
Forms nitrates in reactions.
90
Sulphuric acid
Forms sulphates in reactions.
91
How do you name a salt?
The metal's name in the alkali/base goes first followed by:
Chloride for Hydrochloric Acid
Nitrate for Nitric Acid
Sulphate for Sulphuric Acid
E.g:
Sodium hydroxide + Hydrochloric acid → Sodium chloride + Water
92
pH scale
Measures acidity/alkalinity from 0–14.
93
Acid rain
Formed when SO₂ dissolves in rainwater.
94
Reactivity series
Ranking of metals by reactivity.
95
More reactive metals
Form stronger compounds, harder to extract.
96
Native metals
Unreactive metals found as elements (e.g. gold).
97
What is the reactivity trend for Group 1 & 2 metals
Reactivity increases down the group.
98
What is the reactivity trend for the Halogens
Decreases as you go down the group
99
Halogens
Group 7 elements.
100
Colour of halogens
Light to dark as you go down the group.
101
Displacement among halogens
More reactive halogen displaces less reactive one.
102
Example of halogen displacement
Cl₂ + 2NaBr → 2NaCl + Br₂
