Chemistry Paper 2 Topics Flashcards
What do steep lines mean on rates of reaction graphs?
Steep lines on reaction graphs = fast reaction
How can more products be formed in a reaction?
Increase products by increasing the reactants
What do flat lines represent on a rate of reaction graph?
Flat lines on reaction graphs mean that the reaction has stopped
What is activation energy?
Activation energy is the minimum amount of energy needed for particles to react
What two factors does the rate of reaction depend on?
The rate of reaction depends on collision frequency and collision energy
What is collision frequency?
The collision frequency is the number of collisions between particles in a reaction.
How does collision frequency affect the rate of reaction?
More collisions = faster rate of reaction (as there is more energy)
How does collision energy affect the rate of reaction?
Collision energy affects the rate of reaction as enough energy is needed to be transferred in a collision to overcome activation energy and break the bonds
How does temperature affect the rate of reaction?
Higher temp = faster rate of reaction
Lower temps = slower rate of reaction
How does concentration/pressure affect the rate of reaction?
High concentration/pressure = faster rates of reaction
Low concentration/pressure = slower rates of reaction
How does surface area affect the rate of reaction?
Large surface area = faster rates of reaction
Small surface area = slower rates of reaction
What is a catalyst?
A catalyst speeds up reactions by decreasing activation energy and providing an alternative pathway
How can we reach equilibrium in a reaction?
Equilibrium can be reached when a reversible reaction has taken place in a closed system
What is equilibrium?
Equilibrium is when both reactions happen and cancel each other out
What is a reversible reaction?
A reversible reaction is where the products can react to form the reactants again
Where does equilibrium lie if there are more reactants than products in a reaction?
The equilibrium lies on the left side of the reaction if there are more reactants than products
Where does equilibrium lie if there are more products than reactants in a reaction?
The equilibrium lies on the right side of the reaction if there are more products than reactants
What happens to the concentration of a reaction at equilibrium?
Concentration doesn’t change at equilibrium
What can happen if you change the reaction conditions of a reversible reaction?
Changing the reaction conditions of reversible reactions can cause the direction to change
Where does equilibrium lie if you cool the reaction?
Cooling the reaction means the equilibrium will lie on the left side of a reaction
Where does the equilibrium lie if you heat the reaction?
Heating the reaction means the equilibrium will lie on the right side of a reaction
What will the other direction be in a reaction if one is endothermic?
If one direction of a reaction is endothermic, the other reaction will be exothermic
What does le chatelier’s principle state?
le chatelier’s principle states that if the conditions in a reversible reaction at equilibrium are changed, the system tries to counteract that change
If the temperature of a reaction increases, what will the equilibrium shift to favour?
If the temperature of a reaction increases, the equilibrium shifts to favour the endothermic direction to take in heat energy
If the temperature of a reaction decreases, what will the equilibrium shift to favour?
If the temperature of a reaction decreases, the equilibrium will shift to favour the exothermic reaction to release heat energy
If the pressure increases in a reaction, what will the equilibrium shift to favour?
If pressure increases in a reaction, the equilibrium will shift to favour the side with fewer molecules of gas to reduce the pressure
If the pressure decreases in a reaction, what will the equilibrium shift to favour?
If pressure decreases in a reaction, the equilibrium will shift to favour the side with more molecules of gas to gain pressure
What happens if the concentration of a reagent is changed?
If the concentration of a reagent is changed, the system will respond to reverse the change
How will a system respond where there is an increase in the concentration of reactants?
If there is an increase in the concentration of reactants, the system will make more products
How will a system respond where there is a decrease in the pressure of reactants?
When there is a decrease in pressure of reactants, the system will make more reactants
What are flame tests used for?
Flame tests are used to test for cations in compounds
What colour flame will lithium appear as?
Lithium ions will have a red flame
What colour flame will sodium appear in?
Sodium ions will have a yellow flame
What colour flame will potassium appear in?
Potassium ions will have a purple flame
What colour flame will calcium appear in?
Calcium ions will have an orange flame
What colour flame will copper appear in?
Copper ions will have a green flame
What precipitate will form from sodium hydroxide + aluminium?
Sodium hydroxide + aluminium = white precipitate
What precipitate will form from sodium hydroxide + copper?
Sodium hydroxide + copper = blue precipitate
What precipitate will form from sodium hydroxide + Iron (Fe2+)?
Sodium hydroxide + Iron (Fe2+) = green precipitate
What precipitate will form from sodium hydroxide + Iron (Fe3+)?
Sodium hydroxide + Iron (Fe3+) = brown precipitate
What is the product of ammonium being warmed up? (NH4)
Ammonium will release ammonia gas when warmed up
How do we test for carbonate ions? (CO3^2-)
Carbonate ions can be detected using any dilute acid (Eg hydrochloric acid). Carbon dioxide bubbles will be produced when acid is added. Passing CO2 through limewater will also make it turn cloudy, therefore testing positive for the presence of carbon dioxide /carbonate ions
How do we test for sulfate ions in a solution? (SO4^2-)
We can test for sulfate ions in a solution by adding a few drops of dilute hydrochloric acid and dilute barium chloride solution.
Why do we add acid first in the tests for sulfate and halide ions?
Adding the acid first means that it can react with any carbonate ions that are present so there won’t be any fake results.
What is the process of testing for halide ions?
We can test for halide ions by;
1) . Adding a few drops of dilute nitric acid to sample
2) . Add a few drops of dilute silver nitrate solution
3) . Observe and record the colour of the precipitate that’s formed
What precipitate will form from chloride ions + nitric acid?
Chloride ions + Nitric acid = white precipitate
What precipitate will form from bromide ions + nitric acid?
Bromide ions + nitric acid = cream precipitate
What precipitate will form from iodide ions + nitric acid?
Iodide ions + nitric acid = yellow precipitate
What are the advantages of modern instrumental methods of analysis?
The advantages of modern instrumental methods of analysis include:
- More rapid (produces results faster)
- More accurate (more reliable on identifying elements/compounds
- More sensitive (can detect very small amounts of a substance
What is the order of the method for instrumental methods of analysis?
Stimulus > sample > detector > sample processor (eg amplifier) > Readout (eg computer)
How do you use a flame emission spectroscope to identify metal ions
1) . Sample heated in a flame, light emitted from flame is passed through a spectroscope
2) . The resulting pattern is known as a spectrum
What does the intensity of light of a flame emission spectroscopy determine?
Intensity of light determines concentration the metal ions
How did the early atmosphere develop?
Intense volcanic activity over time caused the build-up of gases over time - originally mostly carbon dioxide
How were oceans formed?
Oceans were formed from water vapour condensing
What was formed from carbonate precipitates?
Carbonate precipitates lead to the formation of layers of sediment eg limestone and coal
What had led to the decrease of carbon dioxide?
The increase in plants’ photosynthesis caused carbon dioxide to decrease. Carbon dioxide also dissolved in the oceans and was trapped in the layers of sediment from carbon precipitates
What did the increase in oxygen from photosynthesis lead to?
Increased oxygen lead to the evolution of animals
What were crude oil and natural gas formed from?
Crude oil and natural gas were formed from compressed plankton deposits
What was coal formed from?
Coal was formed from compressed thick plant deposits
What was limestone formed from?
Limestone was formed from compressed calcium carbonate deposits from shells and marine skeletons
When did algae evolve?
Algae evolved 2.7 billion years ago
What is the symbol equation for photosynthesis?
Photosynthesis = 6CO2 + 6H20 > C6H1206 + 6O2
What percentage of gases make up the atmosphere today?
80% = Nitrogen, 20% = O2, H20 vapour, CO2 and noble gases
What do humans use natural resources for?
We use natural resources for heating, clothing, shelter, transport and food
What is a finite resource?
A finite resource will eventually run out, as it is being used faster than it is being produced
What is a renewable resource?
The renewable resource will never run out as they are made at a similar/faster rate than it is being used
What is a life cycle assessment?
A life cycle assessment is an assessment of the environmental impact of a product over each stage of its life
What is meant by sustainable development?
Sustainable development is meeting the needs of the present society whilst not damaging the lives of the future generation
What are three ways we can improve sustainability?
We can improve sustainability by reducing the number of raw materials used, reusing products, recycling products that can’t be reused
What is the process of phytomining?
Phytomining:
1) . Soil containing copper
2) . Plant in soil
3) . Copper builds up in leaves
4) . Harvested plants burnt - ash contains the copper compounds
What is the process of bioleaching?
Bioleaching:
1) . Low-grade ore + bacteria
2) . Bacteria converts copper compounds into soluble copper compounds
3) . Leachate solution > extracted via electrolysis
What is meant by potable water?
Potable water is safe to drink (not pure)
What is the process of treating groundwater?
Treating groundwater:
1) . Mesh - removing large debris
2) . Sand and gravel filtration - removing smaller solid bits
3) . Sterilisation - killing harmful bacteria/microbes using ozone, uv light or chlorine gas
What is desalination?
Desalination is carried out in areas without much fresh water to make sea water potable
What are the two methods of desalination?
Two methods of desalination include distillation and reverse osmosis
What does distillation do in desalination?
Distillation boils water to seperate it from dissolved salts
What does reverse osmosis do in desalination?
Reverse osmosis is when you pass water through a membrane that only allows water molecules through
What is the method of treating waste water?
Treating waste water:
Screening > sedimentation > anaerobic digestion of organic matter > natural gas or feteriliser
or
screening > sedimentation > aerobic digestion of organic matter > released back into environment
What is ammonia produced in the haber process used for?
Ammonia produced in the haber process is used to make nitrogen-based fertiliser
Describe the method of using the Haber process to make ammonia?
Production of ammonia:
Hydrogen and nitrogen mixed in 3:1 ratio > passes through reaction vessels through trays of iron catalyst > condenser makes liquid ammonia > ammonia removed > unused hydrogen and nitrogen recycled
Why is the Haber process suitable for an industrial scale?
The Haber process is suitable for an industrial scale as the reactants arent too difficult or expensive to obtain
How does a higher temperature affect the yield of the reaction of ammonia?
Higher temperature lowers the yield as it favours the endothermic reverse reaction
How does pressure affect yield?
Pressure and yield is inversely proportional
High pressure = high yield = fast reaction
Low pressure = low yield = slower rate
What are the three key elements of NPK fertilisers?
The three key elements of NPK fertilisers are nitrogen, phosphorus and potassium
What are NPK fertilisers?
NPK fertilisers are formulations of salts containing the right percentages of elements to help plants to grow
What are the product of the reaction between ammonia and nitric acid?
Ammonia + Nitric acid > Ammonium nitrate
Why is ammonium nitrate a good fertiliser?
Ammonium nitrate is a good fertiliser because it contains nitrogen from two sources
How is ammonium nitrate produced in the industry?
In industry, NPK fertilisers are produced in giant vats at a high concentration
What is the result of ammonia being produced in giant vats at high concentrations?
When ammonia is produced in giant vats at high concentrations, it will be a very exothermic reaction, producing a very concentrated ammonium nitrate product
How is ammonium nitrate produced in labs?
Ammonium nitrate is produced by titration and crystallisation at lower concentrations in labs
What is the result of ammonia nitrate being produced by titration and crystallization at low concentrations?
Ammonium nitrate will be a very slow reaction, producing pure ammonium nitrate crystals
How can soluble phosphate salts form?
Soluble phosphate salts form when phosphate rock reacts with acid
Phosphate rock + nitric acid > ?
Phosphate rock + nitric acid > Phosphoric acid + calcium nitrate
Phosphate rock + sulfuric acid > ?
Phosphate rock + sulfuric acid > Calcium sulphate + calcium phosphate
Phosphate rock + phosphoric acid > ?
Calcium phosphate
What are the independent and dependant variables of finding the rate of reaction practical? (magnesium + HCl reacting with hydrogen)
Independent variable = concentration of acid
Dependant variable = volume of gas given off
What are the independent and dependant variables for calculating the rate of reaction by the precipitates formed from a solution
Independant variable = concentration of acid
Dependant variable = time taken for the cross to disappear
How do we identify anions?
Anions can be identified by using a dropping pipette to add a few drops of reagent to a mystery solution
What precipitates is formed from chloride/bromide / iodide reacting with dilute nitric acid and silver nitrate solution
Chloride = white precipitate Bromide = Cream precipitate Iodide = Yellow precipitate
What precipitate is formed from sulfur dioxide reacting with dilute hydrochloric acid and barium chloride solution?
Sulfur dioxide = white precipitate
What observation can be made from carbon dioxide reacting with dilute acid and limewater?
Limewater will turn cloudy in presence of carbon dioxide
What is the general formula for alkanes?
Alkanaes = CNH2N+2
What is the method of catalytic cracking?
Catalytic cracking is when long-chain hydrocarbon vapour reacts with a hot powdered aluminium catalyst
What is the method of steam cracking
Steam cracking is when long-chain hydrocarbon vapour reacts with steam and heat at high temperatures
Why are alkenes more reactive than alkanes?
Alkenes are more reactive than alkanes due to their double bound, making them more useful
What is the general formula for alkenes?
Alkenes = CNH2N
What the uses of alkenes?
Alkenes are used to produce polymers and starting materials of chemicals such as alcohol and plastics
What is incomplete combustion?
Incomplete combustion is when there isnt enough oxygen for fuel to burn completely
What is the reaction for incomplete combustion?
Incomplete combustion = alkene + oxygen > carbon + carbon monoxide + carbon dioxide + water
Why can the production of ammonia nitrate in the industry be more dangerous than in labs?
In industry, the reactants of ammonia nitrate is much more concentrated making it a very exothermic reaction. This danger can be reduced by having heat removed and using it in later stages
