Chemistry Paper 2 Flashcards
1
Q
Mean rate
A
Quantity of reactant used ÷ Time
2
Q
Mean rate (product)
A
Quantity of product formed ÷ Time
3
Q
Units of rate of reaction
A
g/s, cm³/s (or mol/s for HT)
4
Q
Graph interpretation
A
Draw graphs: amount vs time
5
Q
Tangents in graphs
A
Calculate rate at a specific time (HT)
6
Q
Steeper line in graphs
A
Indicates a faster rate
7
Q
Required Practical 5
A
Investigate how changes in concentration affect the rates of reactions by measuring gas volume and observing color change or turbidity.
8
Q
Method (gas production)
A
Add dilute HCl to a conical flask, add magnesium strip, quickly place bung and gas syringe, start timer and record gas volume every 10 seconds, repeat with different acid concentrations.
9
Q
Method (precipitate/cloudiness)
A
Mix sodium thiosulfate and HCl in a conical flask over a cross on paper, start timer and observe until cross disappears, repeat with different concentrations.
10
Q
Concentration/Pressure effect
A
Higher concentration/pressure = more collisions = faster rate
11
Q
Temperature effect
A
Higher temperature = more energetic collisions = faster rate
12
Q
Surface Area effect
A
Larger surface area = more particles exposed = faster rate
13
Q
Catalyst
A
Lowers activation energy = faster reaction
14
Q
Collision theory
A
Particles must collide with enough energy (activation energy) for a reaction to occur.
15
Q
Frequent & energetic collisions
A
More frequent & energetic collisions = faster reaction
16
Q
Catalysts characteristics
A
Not used up in reaction, provide alternative pathway with lower activation energy, increase reaction rate, not included in chemical equation.
17
Q
Example of a catalyst
A
Enzymes = biological catalysts
18
Q
Reversible Reaction
A
Products can react to form original reactants.
19
Q
Reversible Reactions
A
A + B ⇌ C + D
20
Q
Exothermic Reaction
A
One direction of a reversible reaction that releases energy.
21
Q
Endothermic Reaction
A
The reverse direction of a reversible reaction that absorbs energy.
22
Q
Equilibrium
A
In a closed system, forward and reverse reactions happen at the same rate with no overall change in amounts of reactants/products.
23
Q
Le Chatelier’s Principle
A
If a change is made to a system at equilibrium, the system adjusts to counteract that change.
24
Q
Concentration Increase
A
↑ Concentration of reactant shifts equilibrium right, making more product.
25
Product Concentration Decrease
↓ Product concentration shifts equilibrium right to replace product.
26
Temperature Increase
↑ Temperature favors the endothermic direction.
27
Temperature Decrease
↓ Temperature favors the exothermic direction.
28
Pressure Increase
↑ Pressure (gases) shifts equilibrium to the side with fewer molecules.
29
Pressure Decrease
↓ Pressure (gases) shifts equilibrium to the side with more molecules.
30
Crude Oil
A finite resource formed from ancient plankton, mostly made of hydrocarbons.
31
Alkanes
Saturated hydrocarbons with the general formula CₙH₂ₙ₊₂.
32
First Four Alkanes
Methane, Ethane, Propane, Butane.
33
Boiling Point
Increases with larger hydrocarbon molecules.
34
Viscosity
Increases with larger hydrocarbon molecules.
35
Flammability
Decreases with larger hydrocarbon molecules.
36
Complete Combustion
Hydrocarbon + Oxygen → Carbon dioxide + Water, releasing energy.
37
Fractional Distillation
Separates crude oil by boiling points to produce fuels and feedstock for petrochemicals.
38
Cracking
Breaks large hydrocarbons into smaller, useful ones, making alkenes.
39
Test for Alkenes
Bromine water goes from orange to colourless.
40
Alkenes
Functional group: C=C (double bond), general formula: CₙH₂ₙ.
41
Reactions of Alkenes
Combustion produces a smoky flame; addition reactions with Hydrogen, Water, Halogens.
42
Alcohols
Functional group: -OH, general formula: CₙH₂ₙ₊₁OH.
43
First Four Alcohols
Methanol, Ethanol, Propanol, Butanol.
44
Fermentation
Glucose → Ethanol + Carbon dioxide (uses yeast, 30°C, no oxygen).
45
Carboxylic Acids
Functional group: -COOH, first four: Methanoic, Ethanoic, Propanoic, Butanoic acids.
46
Addition Polymerisation
From alkenes where monomers join to form long chain polymers without releasing small molecules.
47
Condensation Polymerisation
Monomers with 2 functional groups form polymer + small molecule (e.g., water).
48
Amino Acids
Have both -NH₂ and -COOH groups, join by condensation to form polypeptides/proteins.
49
DNA
Two polymer chains made from nucleotides, forming a double helix.
50
Pure Substances
Only one element/compound with nothing added, having specific melting and boiling points.
51
Formulations
Useful mixtures made to precise recipes where every component has a specific purpose.
52
Chromatography
Used to separate mixtures (e.g., inks, dyes) involving stationary phase (paper) and mobile phase (solvent).
53
Rf Value
Rf = Distance moved by substance / Distance moved by solvent.
54
Concentration/Pressure
Higher = more collisions = faster rate
55
Temperature
Higher = more energetic collisions = faster rate
56
Surface Area
Larger = more particles exposed = faster
57
Collision Theory
Particles must collide with enough energy (activation energy)
58
Reversible Reaction
Products can react to form original reactants. Notation: A + B ⇌ C + D
59
Exothermic Reaction
One direction of a reversible reaction that releases energy
60
Endothermic Reaction
Reverse direction of a reversible reaction that absorbs energy
61
Equilibrium
In a closed system → forward and reverse reactions happen at same rate
62
Le Chatelier's Principle
Change in conditions shifts equilibrium to counteract the change
63
Crude Oil
Finite resource, formed from ancient plankton, mostly made of hydrocarbons
64
Alkanes
Saturated hydrocarbons, general formula CₙH₂ₙ₊₂
65
Complete Combustion
Hydrocarbon + Oxygen → Carbon dioxide + Water, releases energy
66
Fractional Distillation
Separates crude oil by boiling points to produce fuels and feedstock
67
Cracking
Breaks large hydrocarbons into smaller, useful ones
68
Alkenes
Functional group: C=C (double bond), general formula: CₙH₂ₙ
69
Alcohols
Functional group: -OH, general formula: CnH2n+1OH
70
Carboxylic Acids
Functional group: -COOH
71
Addition Polymerisation
From alkenes, monomers join to form long chain polymers with no small molecules released
72
Condensation Polymerisation
Monomers with 2 functional groups form polymer + small molecule (e.g. water)
73
Amino Acids
Have both: -NH₂ and -COOH groups, join by condensation to form polypeptides/proteins
74
Pure Substances
Only one element/compound with nothing added, have specific melting and boiling points
75
Formulations
Useful mixtures made to precise recipes where every component has a specific purpose
76
Chromatography
Used to separate mixtures (e.g. inks, dyes) involving stationary phase (paper) and mobile phase (solvent)
77
Rf Value
Rf = Distance moved by substance / Distance moved by solvent
78
Rf value
Rf=Distance moved by substance / Distance moved by solvent
79
Hydrogen Test
Burning splint produces a loud pop sound
80
Oxygen Test
Glowing splint relights
81
Carbon Dioxide Test
Bubble into limewater; limewater turns cloudy
82
Chlorine Test
Damp litmus paper bleaches paper white
83
Lithium Ion Flame Colour
Crimson
84
Aluminium Ion Flame Colour
White (dissolves in excess NaOH)
85
Sodium Ion Flame Colour
Yellow
86
Calcium Ion Flame Colour
White
87
Potassium Ion Flame Colour
Lilac
88
Magnesium Ion Flame Colour
White
89
Copper(II) Ion Flame Colour
Blue
90
Copper Ion Flame Colour
Green
91
Iron(II) Ion Flame Colour
Green
92
Iron(III) Ion Flame Colour
Brown
93
Carbonates Reaction
React with dilute acid → fizzing (CO₂)
94
Halides Precipitate with AgNO₃ + HNO₃
Chloride (Cl⁻) forms white precipitate, Bromide (Br⁻) forms cream precipitate, Iodide (I⁻) forms yellow precipitate
95
Sulfates Reaction with BaCl₂ + HCl
Forms a white precipitate (BaSO₄)
96
Flame Tests Procedure
Clean a wire loop with acid, dip into solid/solution of metal ion and place in flame
97
Sodium Hydroxide Tests
Add a few drops of NaOH to solution
98
Al³⁺
white, redissolves in excess NaOH
99
Ca²⁺
white
100
Mg²⁺
white
101
Cu²⁺
blue
102
Fe²⁺
green
103
Fe³⁺
brown
104
Carbonates
Add dilute acid → fizzing → test gas with limewater → goes cloudy = CO₂
105
Sulfates
Add HCl and barium chloride → white precipitate = BaSO₄
106
Chloride
white precipitate when adding nitric acid and silver nitrate
107
Bromide
cream precipitate when adding nitric acid and silver nitrate
108
Iodide
yellow precipitate when adding nitric acid and silver nitrate
109
Advantages of Instrumental Methods
Fast, accurate, sensitive; work with tiny samples; used in forensics, drug testing, pollution analysis
110
Flame Emission Spectroscopy
Sample in flame → light passed through spectroscope; produces line spectrum (unique to each element)
111
Proportions Of Gases in the Atmosphere
~80% Nitrogen, ~20% Oxygen, small amounts of Carbon dioxide, water vapour, noble gases
112
Early Atmosphere
Formed by volcanic activity; mostly carbon dioxide, little/no oxygen; contained water vapour, nitrogen, methane, ammonia
113
Increase In Oxygen
Algae (2.7 billion years ago) and later plants carried out photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
114
Greenhouse Gases
Include CO₂, methane, water vapour; trap energy from the sun by allowing short wavelength radiation in and trapping long wavelength (infrared) radiation
115
Human Activities Increasing Greenhouse Gases
CO₂ from burning fossil fuels, deforestation; Methane from agriculture (cows), landfills
116
Climate Change
Global warming → a type of climate change; potential effects include rising sea levels, extreme weather, reduced biodiversity, changes in species distribution
117
Carbon Footprint
Total greenhouse gases emitted over a product/event's lifetime; reduced by using renewable energy, energy efficiency, carbon capture, eating less meat
118
Burning Fuels
CO₂ from complete combustion causes global warming; CO from incomplete combustion is a toxic gas that prevents O₂ transport in blood; SO₂ from sulfur in fuels causes acid rain and respiratory issues; NOₓ from high temps in engines causes acid rain and asthma; Particulates (soot) from incomplete combustion cause global dimming and health risks
119
Natural Resources and Sustainability
Natural + agricultural resources = food, fuel, clothing, shelter; finite resources are used faster than replaced; sustainable development meets needs now without compromising future generations
120
Potable Water
Choose source (river, lake, groundwater); filter beds remove solids; sterilisation (chlorine, ozone, UV light); for salty water, use desalination (distillation or reverse osmosis - energy intensive)
121
Required Practical 8
Analysis and purification of water samples from different sources, including pH, dissolved solids and distillation.
122
Chloride
Add nitric acid and silver nitrate → white precipitate
123
Bromide
Add nitric acid and silver nitrate → cream precipitate
124
Iodide
Add nitric acid and silver nitrate → yellow precipitate
125
Advantages of Instrumental Methods
Fast, accurate, sensitive; work with tiny samples; used in forensics, drug testing, pollution analysis.
126
Flame Emission Spectroscopy
Sample in flame → light passed through spectroscope; produces line spectrum (unique to each element); shows which metal ions are present and concentration of metal ions.
127
Proportions Of Gases in the Atmosphere
~80% Nitrogen, ~20% Oxygen, small amounts of: Carbon dioxide, water vapour, noble gases.
128
Early Atmosphere
Formed by volcanic activity; mostly carbon dioxide, little/no oxygen; also contained water vapour, nitrogen, methane, ammonia; water vapour condensed → formed oceans.
129
Carbon dioxide removal
Dissolved in oceans → formed carbonates; locked in fossil fuels and sedimentary rocks.
130
Increase In Oxygen
Algae (2.7 billion years ago) and later plants carried out photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
131
Greenhouse Gases
Include CO₂, methane, water vapour; trap energy from the sun: short wavelength radiation enters atmosphere, long wavelength (infrared) radiation is trapped.
132
Human Activities Increasing Greenhouse Gases
CO₂ from burning fossil fuels, deforestation; Methane from agriculture (cows), landfills.
133
Climate Change
Global warming → a type of climate change; potential effects include rising sea levels, extreme weather, reduced biodiversity, changes in species distribution.
134
Carbon Footprint
Total greenhouse gases emitted over a product/event's lifetime; reduced by using renewable energy, energy efficiency, carbon capture, eating less meat.
135
Challenges of Reducing Carbon Footprint
Lifestyle changes, cost, incomplete international cooperation.
136
Burning Fuels
CO₂ from complete combustion causes global warming; CO from incomplete combustion is a toxic gas, prevents O₂ transport in blood; SO₂ from sulfur in fuels causes acid rain, respiratory issues; NOₓ from high temps in engines causes acid rain, asthma; Particulates (soot) from incomplete combustion cause global dimming, health risks.
137
Natural Resources and Sustainability
Natural + agricultural resources = food, fuel, clothing, shelter; finite resources are used faster than replaced (e.g. metals, fossil fuels); sustainable development meets needs now without compromising future generations.
138
Potable Water
Choose source (river, lake, groundwater); filter beds remove solids; sterilisation (chlorine, ozone, UV light); for salty water, use desalination (distillation or reverse osmosis - energy intensive).
139
pH
Using a pH probe or universal indicator to measure the acidity or alkalinity of a solution.
140
Dissolved solids
Substances that remain after evaporating water and observing if residue is left.
141
Distillation
A method to purify water by heating it until it boils and evaporates, then condensing the steam back into a separate container.
142
Waste Water Treatment
The process of treating water from homes and industry through various steps.
143
Screening
The first step in waste water treatment that removes solids.
144
Sedimentation
The process that separates sludge and effluent in waste water treatment.
145
Anaerobic digestion
The breakdown of sludge in the absence of oxygen.
146
Aerobic treatment
The treatment of effluent using oxygen.
147
Phytomining
A process where plants absorb metal compounds, which are then burnt to produce metal-rich ash.
148
Bioleaching
A method where bacteria produce leachate, a solution of metal ions, to extract metals via displacement or electrolysis.
149
Life Cycle Assessment (LCA)
An assessment of the environmental impact of a product across its entire life cycle, including raw materials, manufacture, use, and disposal.
150
Recycling
The process of converting waste materials into new materials to save energy and raw materials.
151
Rusting
The chemical reaction of iron with oxygen and water.
152
Galvanising
The process of coating iron with zinc for sacrificial protection against corrosion.
153
Alloys
Materials made by combining two or more metals.
154
Bronze
An alloy made from copper and tin.
155
Brass
An alloy made from copper and zinc.
156
Gold alloys
Alloys that contain gold, such as 18 carat which is 75% gold.
157
High carbon steel
A type of steel that is strong but brittle.
158
Low carbon steel
A type of steel that is softer and easily shaped.
159
Stainless steel
An alloy of iron and chromium/nickel that is resistant to corrosion.
160
Common glass
Soda-lime glass made from sand, sodium carbonate, and limestone.
161
Borosilicate glass
Glass made from sand and boron trioxide, known for its higher melting point.
162
Thermosoftening plastics
Plastics with weak forces between chains that can melt.
163
Thermosetting plastics
Plastics with cross-links between chains that do not melt.
164
Haber Process
A method used to make ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) under specific conditions.
165
NPK Fertilisers
Fertilisers that contain nitrogen (N), phosphorus (P), and potassium (K) to improve crop yields.
