AQA GCSE Chemistry Paper 2 Exam
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How do you measure the rate of a reaction? -ANSWER By measuring the quantity of a
reactant used or the quantity of product formed over time
What is the equation for calculating the mean rate of a reaction by measuring the
amount of reactant used? -ANSWER Mean rate of reaction = quantity of reactant
used/time taken
What is the equation for calculating the mean rate of a reaction by measuring the
amount of product formed? -ANSWER Mean rate of reaction = quantity of product
formed/time taken
What units can you measure the rate of a reaction in? -ANSWER g/s or cm3/s or mol/s
How do you calculate the rate of a reaction at a specific time from graph of the quantity
of reactant used or the quantity of product formed? -ANSWER By measuring the gradient
of a tangent drawn at that specific time on the graph
What are the five factors that can affect the rate of a reaction? -ANSWER Concentration
of reactants in solution, pressure of reacting gases, surface area of solid reactants,
temperature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a reaction? -
ANSWER Collision theory
What is collision theory? -ANSWER Chemical reactions can occur only when reacting
particles collide with each other and with sufficient energy
What is the activation energy of a reaction? -ANSWER The minimum amount of energy
that particles must have to react
According to collision theory why does increasing concentration of reactant in solution
increase the rate of the reaction? -ANSWER It increases the frequency of collisions and
so increases the rate of reaction
According to collision theory why does increasing the pressure of reacting gases
increase the rate of the reaction? -ANSWER It increases the frequency of collisions and
so increases the rate of reaction
,According to collision theory why does increasing the surface area of solid reactants in
solution increase the rate of the reaction? -ANSWER It increases the frequency of
collisions and so increases the rate of reaction
According to collision theory why does increasing temperature increase the rate of the
reaction? -ANSWER It increases the frequency of collisions and makes the collision more
energetic and so increases the rate of reaction
How do you increase the surface area of a solid reactant? -ANSWER Grind it into a
powder that has smaller particle size
What effect does increasing the temperature of a reaction by 10°C have on the rate of a
reaction? -ANSWER It doubles it
What is a catalyst? -ANSWER A chemical that changes the rate of a chemical reaction
but is not used up in the reaction
How do catalysts increase the rate of a reaction? -ANSWER By providing a different
pathway for the reaction that has a lower activation energy
How do you know in a reaction that a chemical is used in a reaction is a catalyst? -
ANSWER It is not included in the chemical equation for the reaction
What is a reversible reaction? -ANSWER Where the products of a chemical reaction can
react to produce the original reactants
What is the symbol used in reversible reaction equations that shows that the reaction is
reversible? -ANSWER
How can you change the direction of a reversible reaction? -ANSWER By changing the
conditions; for example heating or cooling the reaction
Describe the energy changes in a reversible reaction -ANSWER One direction will be
exothermic and the other direction endothermic
When is equilibrium in a reversible reaction achieved in apparatus which prevents the
escape of reactants and products? -ANSWER When the rate of the forward and reverse
reactions occur at exactly the same rate
What affects the relative amount of all the reactants and products at equilibrium in a
reversible reaction? -ANSWER The conditions
What happens to an equilibrium if any of the conditions change? -ANSWER The system
responds to counteract the change
, What does Le Chatelier's principle predict? -ANSWER The effects of changing conditions
on a system at equilibrium
What affect will changing the concentration of one of the reactants in a reversible
reaction have on the equilibrium? -ANSWER The system will no longer be in equilibrium
and the concentration of all the substances will change until equilibrium is reached
again
What happens when the concentration of a reactant is increased in a reversible
reaction? -ANSWER More products will be formed until equilibrium is reached again
What happens when the concentration of a product is decreased in a reversible
reaction? -ANSWER More reactant will react until equilibrium is reached again
What happens when the temperature of a system in equilibrium is increased? -ANSWER
The relative amount of products at equilibrium increases for an endothermic reaction
OR The relative amount of products at equilibrium decreases for an exothermic reaction
What happens when the temperature of a system in equilibrium is decreased? -ANSWER
The relative amount of products at equilibrium decreases for an endothermic reaction
OR The relative amount of products at equilibrium increases for an exothermic reaction
What happens in gaseous reactions when the pressure of a system in equilibrium is
increased? -ANSWER The equilibrium position shifts towards the side with the smaller
number of molecules as shown by the symbol equation for the reaction
What happens in gaseous reactions when the pressure of a system in equilibrium is
decreased? -ANSWER The equilibrium position shifts towards the side with the larger
number of molecules as shown by the symbol equation for the reaction
Where is crude oil found? -ANSWER In rocks
What is crude oil formed from? -ANSWER The remains of an ancient biomass consisting
mainly of plankton that was buried in mud
What chemically is crude oil? -ANSWER A mixture of a large number of compounds;
mainly hydrocarbons
What is a hydrocarbon? -ANSWER A molecule made up of carbon and hydrogen only
What type of hydrocarbons are most of those found in crude oil? -ANSWER Alkanes
What is the general formula of alkanes? -ANSWER CnH2n + 2
What are the first four members of the homologous series of alkanes called? -ANSWER
Methane, ethane, propane and butane
With Questions And 100%Correct
Answers|Graded A+|100%Guaranteed
Pass||Newest Exam
How do you measure the rate of a reaction? -ANSWER By measuring the quantity of a
reactant used or the quantity of product formed over time
What is the equation for calculating the mean rate of a reaction by measuring the
amount of reactant used? -ANSWER Mean rate of reaction = quantity of reactant
used/time taken
What is the equation for calculating the mean rate of a reaction by measuring the
amount of product formed? -ANSWER Mean rate of reaction = quantity of product
formed/time taken
What units can you measure the rate of a reaction in? -ANSWER g/s or cm3/s or mol/s
How do you calculate the rate of a reaction at a specific time from graph of the quantity
of reactant used or the quantity of product formed? -ANSWER By measuring the gradient
of a tangent drawn at that specific time on the graph
What are the five factors that can affect the rate of a reaction? -ANSWER Concentration
of reactants in solution, pressure of reacting gases, surface area of solid reactants,
temperature and the presence of a catalyst
What theory can we use to explain how various factors affect the rate of a reaction? -
ANSWER Collision theory
What is collision theory? -ANSWER Chemical reactions can occur only when reacting
particles collide with each other and with sufficient energy
What is the activation energy of a reaction? -ANSWER The minimum amount of energy
that particles must have to react
According to collision theory why does increasing concentration of reactant in solution
increase the rate of the reaction? -ANSWER It increases the frequency of collisions and
so increases the rate of reaction
According to collision theory why does increasing the pressure of reacting gases
increase the rate of the reaction? -ANSWER It increases the frequency of collisions and
so increases the rate of reaction
,According to collision theory why does increasing the surface area of solid reactants in
solution increase the rate of the reaction? -ANSWER It increases the frequency of
collisions and so increases the rate of reaction
According to collision theory why does increasing temperature increase the rate of the
reaction? -ANSWER It increases the frequency of collisions and makes the collision more
energetic and so increases the rate of reaction
How do you increase the surface area of a solid reactant? -ANSWER Grind it into a
powder that has smaller particle size
What effect does increasing the temperature of a reaction by 10°C have on the rate of a
reaction? -ANSWER It doubles it
What is a catalyst? -ANSWER A chemical that changes the rate of a chemical reaction
but is not used up in the reaction
How do catalysts increase the rate of a reaction? -ANSWER By providing a different
pathway for the reaction that has a lower activation energy
How do you know in a reaction that a chemical is used in a reaction is a catalyst? -
ANSWER It is not included in the chemical equation for the reaction
What is a reversible reaction? -ANSWER Where the products of a chemical reaction can
react to produce the original reactants
What is the symbol used in reversible reaction equations that shows that the reaction is
reversible? -ANSWER
How can you change the direction of a reversible reaction? -ANSWER By changing the
conditions; for example heating or cooling the reaction
Describe the energy changes in a reversible reaction -ANSWER One direction will be
exothermic and the other direction endothermic
When is equilibrium in a reversible reaction achieved in apparatus which prevents the
escape of reactants and products? -ANSWER When the rate of the forward and reverse
reactions occur at exactly the same rate
What affects the relative amount of all the reactants and products at equilibrium in a
reversible reaction? -ANSWER The conditions
What happens to an equilibrium if any of the conditions change? -ANSWER The system
responds to counteract the change
, What does Le Chatelier's principle predict? -ANSWER The effects of changing conditions
on a system at equilibrium
What affect will changing the concentration of one of the reactants in a reversible
reaction have on the equilibrium? -ANSWER The system will no longer be in equilibrium
and the concentration of all the substances will change until equilibrium is reached
again
What happens when the concentration of a reactant is increased in a reversible
reaction? -ANSWER More products will be formed until equilibrium is reached again
What happens when the concentration of a product is decreased in a reversible
reaction? -ANSWER More reactant will react until equilibrium is reached again
What happens when the temperature of a system in equilibrium is increased? -ANSWER
The relative amount of products at equilibrium increases for an endothermic reaction
OR The relative amount of products at equilibrium decreases for an exothermic reaction
What happens when the temperature of a system in equilibrium is decreased? -ANSWER
The relative amount of products at equilibrium decreases for an endothermic reaction
OR The relative amount of products at equilibrium increases for an exothermic reaction
What happens in gaseous reactions when the pressure of a system in equilibrium is
increased? -ANSWER The equilibrium position shifts towards the side with the smaller
number of molecules as shown by the symbol equation for the reaction
What happens in gaseous reactions when the pressure of a system in equilibrium is
decreased? -ANSWER The equilibrium position shifts towards the side with the larger
number of molecules as shown by the symbol equation for the reaction
Where is crude oil found? -ANSWER In rocks
What is crude oil formed from? -ANSWER The remains of an ancient biomass consisting
mainly of plankton that was buried in mud
What chemically is crude oil? -ANSWER A mixture of a large number of compounds;
mainly hydrocarbons
What is a hydrocarbon? -ANSWER A molecule made up of carbon and hydrogen only
What type of hydrocarbons are most of those found in crude oil? -ANSWER Alkanes
What is the general formula of alkanes? -ANSWER CnH2n + 2
What are the first four members of the homologous series of alkanes called? -ANSWER
Methane, ethane, propane and butane
