Reactions, Chemicals, Substances etc. Flashcards
(110 cards)
1
Q
What is Hydroxide present in?
A
Alkaline solutions
2
Q
Can simple covalent molecules conduct electricity?
A
No
3
Q
Why do covalent compounds not conduct electricity?
A
Have no free-moving charged particles
4
Q
What force is present between ions?
A
Electrostatic force of attraction
5
Q
What force is present between molecules?
A
Intermolecular force of attraction
6
Q
How big are nanoparticles?
A
Between 1 and 100 nanometres
7
Q
What very useful property do nanoparticles have?
A
Very large surface area : volume ratio
8
Q
Name a product which commonly uses nanoparticles
A
Sun cream
9
Q
Are simple molecular substances usually soluble?
A
Yes
10
Q
Do fullerenes have high or low melting points?
A
Low
11
Q
Do nanotubes have high or low melting points?
A
High
12
Q
What is a substances RFM in grams equal to?
A
Equal to one mole of the substance
13
Q
Why is diamond hard?
A
It is a giant covalent structure, carbon atoms are held by strong covalent bonds
14
Q
What is the typical diameter of a simple covalent compound, such as water?
A
2.8 x 10^-10 m
15
Q
In metres, what is the typical diameter of an atom?
A
1 x 10^-10 m
16
Q
What type of substance usually contains two or more elements?
A
Ionic lattice
17
Q
What is the chemical symbol for hydrochloric acid?
A
HCl
18
Q
What is the chemical symbol for sulfuric acid?
A
H2SO4
19
Q
What is the chemical symbol for iron oxide?
A
Fe2O3
20
Q
What is the chemical symbol for citric acid?
A
C6H8O7
21
Q
Describe the atom arrangement in an ionic lattice
A
A regular arrangement, atoms with different charges are next to eachother
22
Q
Are ionic compounds soluble?
A
Yes
23
Q
Are giant covalent compounds soluble?
A
No
24
Q
Why are metals malleable?
A
Layers of metal ions free to slide over each other when a force is applied
25
What ions do acids produce when dissolved in water?
Hydrogen ions, H+
26
What ions do alkalis produce when dissolved in water?
Hydroxide ions, OH-
27
Name 2 standard lab acids
Hydrochloric, nitric, sulfuric
28
Name 2 standard lab alkalis
Sodium hydroxide, calcium hydroxide, potassium hydroxide
29
Name 3 acids
Hydrochloric, nitric, sulfuric
30
Name 2 bases
Calcium oxide, magnesium oxide, copper oxide
31
Name 2 alkalis
Sodium hydroxide, potassium hydroxide, calcium hydroxide
32
What are the chemical equations for:
-hydrochloric acid
-calcium oxide
-sodium hydroxide
HCl
CaO
NaOH
33
What are the chemical equations for:
-nitric acid
-magnesium oxide
HNO3
MgO
34
What are the chemical equations for:
-sulfuric acid
-copper oxide
H2SO4
CuO
35
What are the chemical equations for:
-potassium hydroxide
-calcium hydroxide
KOH
Ca(OH)2
36
What salts do the following make:
-hydrochloric acid
-sulfuric acid
-nitric acid
Chloride
Sulfate
Nitrate
37
What happens to acids in a solution?
Dissociate
38
What happens to *strong* acids in a solution?
Fully dissociate
39
What happens to *weak* acids in a solution?
Partially dissociate
40
With higher hydrogen concentration, is pH higher or lower?
Lower
41
What is the specific heat capacity of water?
4200 J/kg oC
42
What do alkalis release in water?
-what does this do to pH?
-why?
Hydroxide ions (OH-)
-increase pH
-decreases concentration of hydrogen ions (H+)
43
The ________ is logarithmic
pH scale
44
When pH changes by one, how much does hydrogen ion concentration change by?
10x
45
What is the chemical formula for an ammonium ion?
NH₄⁺
46
What is the chemical formula for a hydroxide ion?
OH⁻
47
What is the chemical formula for a sulphate ion?
SO₄²⁻
48
What is the chemical formula for a carbonate ion?
CO₃²⁻
49
What is the chemical formula for a nitrate ion?
NO₃⁻
50
Acid + ____ -> salt + water
Base
51
___ + base -> salt + water
Acid
52
Acid + base -> ______
Salt + water
53
Acid + ___ -> salt + hydrogen
Metal
54
___ + metal -> salt + hydrogen
Acid
55
Acid + metal -> ______
Salt + hydrogen
56
___ + carbonate -> salt + water + carbon dioxide
Acid
57
Acid + ___ -> salt + water + carbon dioxide
Carbonate
58
Acid + carbonate -> ___
Salt + water + carbon dioxide
59
During titration, are the acid and base partially or completely ionised?
Completely
60
What does titration result in the formation of?
Water and a soluble salt
61
Name the 14 common elements (including carbon and hydrogen) from the reactivity series in decreasing order of reactivity
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Lead
Hydrogen
Copper
Silver
Gold
Platinum
62
Name the 5 elements from the reactivity series which are extracted via electrolysis
Potassium
Sodium
Calcium
Magnesium
Aluminium
63
Name the 4 elements from the reactivity series which are extracted by reduction with carbon
Zinc
Iron
Lead
Copper
64
Name the 3 elements from the reactivity series which don’t need to be extracted
-why do they not need to be extracted?
Silver
Gold
Platinum
-are found naturally in their native state and not in an ore
65
Describe a technique to test whether hydrogen gas is produced in a chemical reaction
Put a lit splint into the reaction vessel. If hydrogen is present, a squeaky pop can be heard since hydrogen is flammable
66
By what method would iron be extracted from its ore?
-why?
Reduction, heated with carbon
-less reactive than carbon so it will be displaced by carbon dioxide
67
In the electrolysis of aluminium, what happens at the cathode?
Aluminium ions form atoms
68
In the electrolysis of aluminium, why is it dissolved in cryolite rather than being melted?
Reduces melting point of aluminium
69
What is cryolite?
An aluminium compound
70
What happens to aluminium metal during electrolysis?
It sinks to the bottom
71
In the electrolysis of aluminium, what happens to oxygen?
Reacts with carbon at the anode to form carbon dioxide
72
In the electrolysis of aluminium why does the anode need replacing?
It burns away
73
What is bauxite?
Aluminium ore
74
Why can aluminium *not* be extracted by heating with carbon?
Aluminium is more reactive so it won’t be displaced
75
During crystallisation, why is the base added in excess?
To ensure the acid fully reacts and to form a pure salt
76
During crystallisation, why is the base filtered?
Filtered to remove excess base and form a pure salt
77
During crystallisation, why is the solution heated *gently*?
To allow crystallisation
78
During calorimetry, why is an insulated cup with a lid used?
Minimise heat loss/gain from/to the surroundings
79
During calorimetry, what should you do to ensure the reactants are fully mixed?
Use a stirring rod
80
Is breaking bonds endo- or exothermic?
Endothermic
81
Is forming bonds endo- or exothermic?
Exothermic
82
What is activation energy?
Minimum energy required for a reaction to take place
83
What is a reaction profile?
A graph that shows how the energy in a reaction changes as the reaction progresses
84
How do you calculate bond energy? (Hint: BERP)
Bond Energy = Reactants - Products
85
Define an electric cell
A device that contains a store of chemicals that react to produce a voltage that can push current around an electric circuit
86
Give 2 examples of electric cells
Alkaline and Lithium cells
87
How can an electric cell be made?
Connecting two different metals in contact with an electrolyte
88
In an electric cell, the metal with the higher ______ pushes electrons towards the other metal
Reactivity
89
The bigger difference in reactivity of electrodes, the ______ the voltage (electric cell)
Greater
90
What is the unit for specific latent heat?
J/kg C (Celsius)
91
Define specific latent heat
The energy needed to change state of 1kg of a substance
92
Define fuel cell
-what is usually used as fuel?
A device that produces a voltage when supplied with a fuel and oxygen
-hydrogen
93
Give 2 examples of fuel cells
Methanol fuel cells, hydrogen fuel cells
94
What is the symbol equation for the reaction in a hydrogen fuel cell? Include state symbols
2H2 (g) + O2(g) -> 2H2O(g)
95
What are the 2 reactants in a hydrogen fuel cell?
-what waste product is formed?
Hydrogen and oxygen
-water
96
At the anode of a hydrogen fuel cell, what happens to hydrogen atoms?
Oxidised to become hydrogen ions
97
When hydrogen is oxidised at the anode of a hydrogen fuel cell, where do the electrons go?
Taken by the anode and pass through a wire to the cathode
98
When hydrogen is oxidised at the cathode of a hydrogen fuel cell, where do the hydrogen ions go? (And through what?)
Hydrogen ions move through the electrolyte to the cathode
99
What is the half (symbol) equation for hydrogen being oxidised at the anode of a hydrogen fuel cell?
H2 -> 2H+ + 2e-
100
At the cathode of a hydrogen fuel cell, what 2 particles react with oxygen molecules?
Electrons and hydrogen
101
At the cathode of a hydrogen fuel cell, what product is formed?
-what particle has been reduced?
Water
-oxygen
102
Where is energy released in a hydrogen fuel cell?
At the cathode
103
What is the half (symbol) equation for the reaction occurring at the cathode of a hydrogen fuel cell? Include electrons
02 + 4H+ + 4e- -> 2H20
104
In a hydrogen fuel cell, what is oxidised/reduced at both the anode and cathode?
At anode) hydrogen is oxidised
At cathode) oxygen is reduced
105
Name 2 advantages of hydrogen fuel cells
-no greenhouse gases formed
-longer lifespan
-good supply of oxygen and hydrogen gas
106
Name 2 disadvantages of hydrogen fuel cells
-dangerous (explosive) if hydrogen mixed with oxygen
-hydrogen not a renewable energy source
-fossil fuels used to extract
107
What is produced in a neutralisation reaction?
Salt and water
108
What colour does phenophthalein turn in an alkali?
Pink
109
Write a *word* equation for the overall reaction in a hydrogen fuel cell
Hydrogen + oxygen -> water
110
Define weak acid
An acid that partially ionises in an aqueous solution
