Chemistry Paper 2 Flashcards
What two equations can be used to measure the rate of a reaction?
mean rate of reaction = (quantity of reactant used) / time
mean rate of reaction = (quantity of product formed) / time
List the 5 things that can affect the rate of a reaction.
Concentration (of solutions)
Pressure (of gases)
Surface area (of solids)
Temperature
Catalysts
What is the name for the minimum amount of energy needed for a reaction to happen?
Activation Energy
What theory states that chemical reactions only occur when reacting particles collude with enough energy?
Collision Theory
Explain how surface area affects the rate of reaction.
Increasing the surface area …
…increases the frequency of collisions…
…and so increases the rate of reaction.
What is a catalyst?
Something that increases the rate of a reaction without being used up in the reaction.
Explain how temperature affects the rate of reaction.
Increasing temperature…
…Increases the frequency of collisions…
…The collisions are more energetic.
What does ‘equilibrium’ mean?
In a reversible reaction, the forward and reverse reactions occur at exactly the same rate.
If a reversible reaction is endothermic in forward direction, what will it be in the reverse direction?
Exothermic
What is crude oil a mixture of?
Hydrocarbons
What is Le Chatelier’s Principle?
The idea that if you change the conditions(such as temperature and pressure) of a reversible reaction at equilibrium, the system will try to counteract the change.
The ancient remains of plankton and other marine organisms is the origin of what finite resource?
Crude oil
What is the general formula for a homologous series of alkanes?
CnH2n+2
Name three useful fuels obtained from crude oil.
Any three from:
petrol
diesel
kerosene
heavy fuel oil
liquefied petroleum gas
What process is used to separate the hydrocarbons found in crude oil?
Fractional Distillation
What are the products of cracking?
Alkanes and Alkenes
Name two useful materials that can be made from crude oil by the petrochemical industry.
Any two from:
solvents
lubricants
polymers
detergents.
What are the products of complete combustion of a hydrocarbon?
carbon dioxide (CO2) and water (H2O)
Explain how fractional distillation of crude oil works.
Crude oil (a mixture of different length hydrocarbons) is heated.
Different length fractions have different boiling points. When heated, the fractions evaporate and rise up the tower.
The fractions cool down as they rise up the tower. When they reach their condensing point, they will condense, turn into a liquid and flow out of the tower.
Which are more reactive? Alkanes or Alkenes?
Alkenes are more reactive than their related alkanes
What is the chemical meaning of a ‘pure’ substance?
What is the every day meaning of a ‘pure’ substance?
In Chemistry: A single element or compound that is not mixed with any other substance.
In everyday language: A substance that hasn’t had anything added to it, e.g. pure milk.