C8: Rates and equilibrium 1

Question 1

what is the rate of a reaction

Answer 1

how quickly reactants are used up or products are produced

Question 2

what is the equation for calculating the mean rate of reaction

Answer 2

mean rate = change in quantity of product or reactant/time taken

Question 3

what is the unit for rate of reaction in a reaction involving a change in mass

Answer 3

g/s

Question 4

what is the unit for rate of reaction in a reaction involving a change in volume

Answer 4

cm/s

Question 5

what is the activation energy

Answer 5

the minimum amount of energy colliding particles have to have before a reaction will take place

Question 6

what effect does increasing concentration have on the rate of reaction

Answer 6

increases

Question 7

why does increasing the concentration have this effect

Answer 7

more reactant particles in the same volume lead to more frequent collisions

Question 8

what does the effect of increasing the pressure have on the rate of reaction

Answer 8

increases

Question 9

why does increasing the pressure cause this effect

Answer 9

less space between particles means more frequent collisions

Question 10

what effect does increasing the surface area have on the rate of reaction

Answer 10

increases

Question 11

why does increasing surface area have on the rate of reaction

Answer 11

more reactant particles are exposed and able to collide leading to more frequent collisions

Question 12

what effect does increasing temperature have on the rate of reaction

Answer 12

increases

Question 13

why does increasing temperature have this effect

Answer 13

particles move faster, leading to more frequent collision - particles have the same activation energy, so more collisions result in a reaction

Question 14

what is a catalyst

Answer 14

a substance that increases the rate of a reaction but is not used up in the reaction

Question 15

how do catalysts increase the rate of reaction

Answer 15

lower the activation energy of the reaction, so more collisions result in a reaction

Question 16

what is a reversible reaction

Answer 16

the reactants turn into products and the products turn into reactants

Question 17

which symbol shows a reversible reaction

Answer 17

⇌

Question 18

what is dynamic equilibrium

Answer 18

the point in a reversible reaction when the rate of the forward and reverse reactions are the same

Question 19

what are the three reaction conditions that can be changed

Answer 19

concentration, temperature, pressure

Question 20

what is Le Chatelier’s principle

Answer 20

the position of equilibrium will shift to oppose external changes

Question 21

what is the effect of increasing the concentration of reactants on a reaction at dynamic equilibrium

Answer 21

favours the forward reaction

Question 22

what is the effect of decreasing the concentration of products on a reaction at dynamic equilibrium

Answer 22

favours the forward reaction

Question 23

what is the effect of increasing pressure on a reaction at dynamic equilibrium

Answer 23

favours the reaction with the fewest molecules

Question 24

what is the effect of decreasing pressure on a reaction at dynamic equilibrium

Answer 24

favours the reaction that leads to the most molecules

Question 25

what is the effect of increasing temperature on a reaction at dynamic equilibrium

Answer 25

favours the endothermic reaction

Question 26

what is the effect of decreasing temperature on a reaction at dynamic equilibrium

Answer 26

favours the exothermic reaction