C8 Rates and Equilibrium

Question 1

what is the rate of reaction like at the beginning of the reaction?

Answer 1

the reaction is very fast. there is a lot of product being made in a short amount of time

Question 2

why is the rate of reaction fast at the beginning of the reaction?

Answer 2

there are a lot of reactant molecules which can collide and form the products

Question 3

why does the rate of a reaction decrease over time?

Answer 3

a lot of the reactant molecules have already reacted and produced the products
this means there are less molecules to react and form the products

Question 4

why does a reaction stop?

Answer 4

all the reactant molecules have reacted

Question 5

how can you measure the rate of a reaction?

Answer 5

measure the amount of product formed or the amount of reactant used over time

Question 6

how do you work out the mean rate of reaction?

Answer 6

quantity of product formed or reactant used / time taken

Question 7

what does the slope of a graph give? (when measuring the amount of product formed/reactant used over time)

Answer 7

the rate of reaction

Question 8

if a graph has a curved line, what does this mean?

Answer 8

the slope is constantly changing so the rate is constantly changing

Question 9

what does a tangent do?

Answer 9

gives the rate of the reaction at a specific point when the graph is a curve

Question 10

what are the ways you increase the rate of reaction in terms of collisions?

Answer 10

the energy of collisions
the number of collisions

Question 11

what are the ways you increase the rate of reaction?

Answer 11

increase:
concentration
temperature
pressure
surface area
catalyst

Question 12

why does an increase in surface area, pressure and concentration increase the rate of reaction?

Answer 12

there are a greater number of collisions of the reactions likely to happen.

Question 13

why does a catalyst increase the rate of reaction?

Answer 13

it increases the likelihood of collisions as it provides an easier path for the reactants to meet

Question 14

how does temperature increase the rate of reaction?

Answer 14

it increases the energy of collisions and the likelihood of collisions happening

Question 15

what is a reversible reaction?

Answer 15

a reaction in which teh products can re-form the reactants

Question 16

what is a fact about the energy released and taken in in a reversible reaction?

Answer 16

the amount of energy transferred to the surroundings in one direction is equal to the energy transferred back in the opposite direction

Question 17

what are the properties of the forward and reverse reactions of a reversible reaction in terms of energy?

Answer 17

one is exothermic
the other is endothermic

Question 18

what is dynamic equilibrium?

Answer 18

in a reversible reaction, the rate of the forward reaction equals the rate of the reverse reaction

Question 19

what is Le Chatelier’s principle?

Answer 19

when a change in conditions is introduced to a system at equilibirum, the position of equilibrium shifts to cancel out the change

Question 20

what happens if pressure is increased in terms of a reversible reaction?

with gases

Answer 20

the reaction that has fewer molecules is favoured

Question 21

what happens if pressure is decreased in terms of a reversible reaction?

with gases

Answer 21

the reaction with the greater number of molecules is favoured

Question 22

what happens if the temperature is increased with reversible reactions?

Answer 22

the endothermic reaction is favoured

Question 23

what happens when the temperature is decreased with reversible reactions?

Answer 23

the exothermic reaction is favoured