The rate and extent of chemical change

Question 1

what are the 2 ways of measuring rate of reaction?

Answer 1

how fast reactants are used up OR how fast products are being formed

Question 2

what are the equations for average rate of reaction?

Answer 2

quantity of products formed/ time OR quantity of reactants used/ time

Question 3

what are the factors affecting rate of reaction?

Answer 3

temp, concentration/ pressure, surface area, catalyst.

Question 4

what is collision theory?

Answer 4

in order for particles to react, they have to collide with each other with sufficient energy.

Question 5

what does the rate of collision theory depend on?

Answer 5

amount of energy particles have and the frequency of collisions.

Question 6

why does rate of reaction increase if energy particles have is higher?

Answer 6

they have more energy to transfer during collisions.

Question 7

why is frequency of collisions important for collision theory?

Answer 7

the particles will collide more so there will be more successful collisions.

Question 8

how does temperature increase rate of reaction?

Answer 8

as temp increases particles gain more energy which means they move faster, so they collide more frequently. they will also collide with more energy. higher rate of successful collisions

Question 9

how does increased concentration/ pressure increase rate of reaction?

Answer 9

more particles per unit of volume means collisions will be more frequent. this means increased successful collisions

Question 10

how does increasing the surface area (to volume ratio) increase the rate of reaction?

Answer 10

much higher area where collisions can take place meaning collisions frequency would increase.

Question 11

what is a catalyst?

Answer 11

substances that speed up a reaction but are not used up in the reaction themselves.

Question 12

how does a catalyst increase the rate of reactions?

Answer 12

creates an alternative reaction pathway with a smaller activation energy, meaning a higher proportion of successful collisions.

Question 13

what are the most common catalysts?

Answer 13

transition metals (e.g. cobalt and nickel) and enzymes.

Question 14

what is the equilibrium of reversible reactions?

Answer 14

concentrations of reactants used up and products won’t change anymore SO both reactions are still happening but they cancel each other out

Question 15

how does the position of equilibrium change?

Answer 15

when there are more products the equilibrium lies to the right but more reactants and less products it lies to the left.

Question 16

how does adding heat change the equilibrium?

Answer 16

it encourages the forward reaction meaning we will have more products. this means the position of equilibrium will move to the right.

Question 17

what is a closed system?

Answer 17

a sealed environment from which none of the reactants or products can escape.

Question 18

are reversible reactions endothermic or exothermic?

Answer 18

they are exothermic one way and endothermic the other way.

Question 19

what is le chatelier principle?

Answer 19

change in conditions of a reversible reaction then the position of equilibrium will shift to try to counteract the change

Question 20

what 3 factors affect position of equilibrium?

Answer 20

temp, concentration and pressure.

Question 21

if there is an increase in pressure which side will the equilibrium move to?

Answer 21

smaller number of gas molecules