C3 Flashcards
1
Q
Metals are represented in equations by what type of formula?
A
Empirical formula
2
Q
Ionic compounds are represented in equations by what type of formula?
A
Empirical formula
3
Q
Simple covalent molecules are represented in equations by what type of formula?
A
Molecular formula
4
Q
What is the formula for carbon dioxide?
A
CO2
5
Q
Bromine is a halogen
What is the formula for bromine?
A
Br2
6
Q
What is the formula for nitrogen?
A
N2
7
Q
What is the formula for oxygen?
A
O2
8
Q
What is the formula for sulfur?
A
S
9
Q
Potassium is a metal
What is the formula for potassium?
A
K
10
Q
Aluminium is a metal
What is the formula for aluminium?
A
Al
11
Q
What is the formula for sodium chloride?
A
NaCl
12
Q
What is the formula for magnesium bromide?
A
MgBr2
13
Q
What is the formula for lithium oxide?
A
Li2O
14
Q
Phosphorus exists as simple molecules
What is the formula for phosphorus?
A
P4
15
Q
Iodine is in group 7
What is the formula of an iodide ion?
A
I-
16
Q
Chlorine is in group 7
What is the formula of a chloride ion?
A
Cl-
17
Q
Sulfur is in group 6
What is the formula of a sulfide ion?
A
S2-
18
Q
Oxygen is in group 6
What is the formula of an oxide ion?
A
O2-
19
Q
Nitrogen is in group 5
What is the formula of a nitride ion?
A
N3-
20
Q
Sulfate is a complex ion
What is the formula of a sulfate ion?
A
SO42-
21
Q
Nitrate is a complex ion
What is the formula of a nitrate ion?
A
NO3-
22
Q
Carbonate is a complex ion
What is the formula of a carbonate ion?
A
CO32-
23
Q
Calcium is in group 2
What is the formula of a calcium ion?
A
Ca2+
24
Q
What is the formula for methane?
A
CH4
25
What is the formula for sulfur dioxide?
SO2
26
What is the formula for sulfur trioxide?
SO3
27
What is the formula for carbon monoxide?
CO
28
What is the formula for silicon dioxide?
SiO2
29
What is the formula for potassium nitrate?
KNO3
30
What is the formula for lithium carbonate?
Li2CO3
31
What is the formula for iron(III) oxide
Fe2O3
32
What is the formula for a copper(II) ion?
Cu2+
33
What is the formula for a silver ion?
Ag+
34
What is the formula of sodium sulfate?
Na2SO4
35
In terms of structure, how do the group 7 elements exist?
Diatomic molecules
36
In terms of structure, how do the group 0 elements exist?
Monatomic gases
37
What is the half equation for sodium ions being produced from sodium?
Na --> Na+ + e-
38
What is the half equation for magnesium ions being produced from magnesium?
Mg --> Mg2+ + 2e-
39
What is the half equation for magnesium ions being produced from aluminium?
Al --> Al3+ + 3e-
40
What is the half equation for oxide ions being produced from oxygen?
O2 + 4e- --> 2O2-
41
What is the half equation for bromide ions being produced from bromine?
Br2 + 2e- --> 2Br-
42
What does Avogadro's constant tell us?
The number of entities in one mole
43
What is the S.I. unit of measurement of amount of substance?
The mole (mol)
44
What is the value of Avogadro's constant (including units)?
6.02 x 1023 /mol
45
How many **moles** of hydrogen atoms are contained in 3 mol of water molecules?
6 mol
46
What is meant by molar mass?
The mass of 1 mole of a substance
47
What are the units for molar mass?
g/mol
48
What is the molar mass of methane?
| Ar of carbon = 12.0
Ar of hydrogen = 1.0
16 g/mol
49
What is an exothermic reaction?
A reaction where energy is transferred (given out) to the surroundings
50
What is an endothermic reaction?
A reaction where energy is transferred (taken in) from the surroundings
51
What happens to the temperature when an exothermic reaction takes place
The temperature increases
52
What happens to the temperature when an endothermic reaction takes place?
The temperature decreases
53
Are combustion reactions exothermic or endothermic?
Exothermic
54
What is the definition of bond energy?
The energy required to break 1 mole of a particular bond
55
Is bond breaking exothermic or endothermic?
Endothermic
56
Is bond making exothermic or endothermic?
Exothermic
57
What sort of reaction is this?
Endothermic
58
What sort of reaction is this?
Exothermic
59
Which arrow represents the overall energy change?
Arrow A
60
Which arrow represents the activation energy?
Arrow C
61
Define oxidation in terms of the transfer of oxygen
Gain of oxygen by a substance
62
Define reduction in terms of the transfer of oxygen
Loss of oxygen by a substance
63
Define oxidation in terms of electrons
Oxidation is a loss of electrons
64
Define reduction in terms of electrons
Reduction is a gain of electrons
65
What is a redox reaction?
A reaction where both oxidation and reduction happen at the same time
66
Oxidation or reduction?
Al --> Al3+ + 3e-
Oxidation
67
Oxidation or reduction?
Fe3+ + 3e- --> Fe
Reduction
68
What happens to an oxidising agent during a redox reaction?
It gets reduced
69
What happens to a reducing agent during a redox reaction?
It gets oxidised
70
Which species is being oxidised?
Mg(s) + CuO(s) --> MgO(s) + Cu(s)
Magnesium
71
Which species is the oxidising agent?
Mg(s) + CuO(s) --> MgO(s) + Cu(s)
Copper oxide
72
What is an acid?
A substance which releases H+ ions when dissolved in water
73
What is a base?
A substance which can neutralise acids
74
What is an alkali?
A base which is soluble in water
75
What is the pH of an acidic solution?
Less than 7
76
What is the pH of an alkaline solution?
Greater than 7
77
What is the pH of a neutral solution?
7
78
Name an indicator other than litmus or universal indicator
Methyl orange or phenolphthalein
79
What is the general word equation for neutralisation?
acid + base --> salt + water
80
What happens to the pH if a base or alkali is added to an acid?
It increases
81
What type of salts are formed from hydrochloric acid?
Chlorides
82
What type of salts are formed from nitric acid?
Nitrates
83
What type of salts are formed from sulfuric acid?
Sulfates
84
What type of salts are formed from phosphoric acid?
Phosphates
85
Which acid could have formed this salt?
Na3PO4
Phosphoric acid
86
Which acid could have formed this salt?
MgSO4
Sulfuric acid
87
Which compound would react with hydrochloric acid to produce CuCl2?
| More than one answer is possible
Copper oxide
OR
Copper hydroxide
OR
Copper carbonate
88
What is the ionic equation for neutralisation?
H+(aq) + OH-(aq) --> H2O(l)
89
What is the general word equation for the reaction between an acid and a carbonate?
acid + carbonate --> salt + water + carbon dioxide
90
What is the general word equation for the reaction between an acid and a metal?
acid + metal --> salt + hydrogen
91
What is a dilute acid?
A solution of acid with a low ratio of acid to volume of solution (i.e. a low concentration of acid)
92
What is a concentrated acid?
A solution of acid with a high ratio of acid to volume of solution (i.e. a high concentration of acid)
93
What is a strong acid?
An acid that is fully ionised in solution
94
What is a weak acid
An acid that is partially ionised in solution
95
What is the name of the type of graph shown?
pH titration curve
| for a **strong** acid added to a **strong** alkali
96
At what point on the graph is the concentration of hydroxide ions greatest?
0 cm3 (pH 13)
97
At what point on the graph is the concentration of H+ ions greatest?
50 cm3 (pH 1.4)
98
At what volume of acid added is the concetration of hydrogen and and hydroxide exactly equal?
25 cm3
99
What is electrolysis?
A process in which an electric current is passed through a compound, causing a chemical change.
100
What is the name for the solution or liquid in electrolysis which contains mobile ions and conducts electricity?
Electrolyte
101
What is the name for the two inert substances (often graphite) used in electrolysis.
Electrodes
102
What is the name of the positive electrode in electrolysis?
The anode
103
What is the name of the negative electrode in electrolysis?
The cathode
104
What happens to positive ions during electrolysis?
They gain electrons at the cathode
105
What happens to negative ions during electrolysis?
They lose electrons at the anode
106
What are positive ions known as?
Cations
107
What are negative ions known as?
Anions
108
What is meant by the term "discharged" in the context of electrolysis?
When ions gain or lose electrons to become atoms or molecules at an electrode
109
What would be the product formed at the anode in the electrolysis shown?
Bromine (Br2)
110
What would be the product formed at the cathode in the electrolysis shown?
Lead (Pb)
111
At which electrode is oxidation occuring?
Anode
112
At which electrode is reduction occuring?
Cathode
113
Why do salts need to be molten or dissolved in solution to be electrolysed?
Because the ions in a solid salt cannot move, so cannot conduct electricity.
114
What two ions are always present in the electrolysis of an aqueous solution?
H+ and OH-
115
During the electrolysis of water, what is produced at the cathode?
Hydrogen
116
During the electrolysis of water, what is produced at the anode?
Oxygen
117
When water is electrolysed, what is the half equation for the reaction that occurs at the cathode?
4H+ + 4e- --> 2H2
| OR 2H+ + 2e- --> H2
118
When water is electrolysed, what is the half equation for the reaction that occurs at the anode?
4OH- --> O2 + 2H2O + 4e-
119
In the electrolysis of solutions, what rule can be used to predict what is produced at the cathode?
If ions from a metal that is more reactive than hydrogen are present, hydrogen ions are discharged to form **hydrogen**. If ions from a metal that is less reactive than hydrogen are present, the metal ions are discharged to form the **metal**.
120
In the electrolysis of solutions, what rule can be used to predict what is produced at the anode?
Oxygen is produced at the anode, unless halide (group 7) ions are present (in high enough concentration), in which case the halogen (group 7 element) is produced.
| in GCSE chemistry, you can assume a suffiecient concentration of halide
121
Which of these metals are more reactive than hydrogen?
sodium; copper; gold
sodium
122
Which of these metals is less reactive than hydrogen?
platinum; lead; aluminium
platinum
123
What would be formed at the cathode during the electrolysis of aqueous potassium chloride?
hydrogen
124
What would be formed at the anode during the electrolysis of aqueous potassium chloride?
chlorine
125
What would be formed at the cathode during the electrolysis of aqueous copper sulfate?
copper
126
What would be formed at the anode during the electrolysis of aqueous copper sulfate?
oxygen
127
What would be formed at the cathode during the electrolysis of aqueous sodium hydroxide?
hydrogen
128
What would be formed at the anode during the electrolysis of aqueous sodium hydroxide?
oxygen
129
If you want to coat a piece of copper with silver by electroplating, what should the anode be made of?
silver
130
If you want to coat a piece of copper with silver by electroplating, what should the cathode be made of?
the piece of copper
131
If you want to coat a piece of copper with silver by electroplating, what would be a suitable electrolyte?
silver nitrate solution
| nitrate salts are commonly used as they have good solubility
132
In the purification of copper by electrolysis which electrode consists of the impure copper?
the anode
133
In the purification of copper by electrolysis which electrode consists of the pure copper?
the cathode
134
In the purification of copper by electrolysis what happens to the impurities?
They fall from the anode and collect at the bottom of the electrolyte
