Measuring Rates Of Reaction

Question 1

What is rate of reaction?

Answer 1

The speed at which a reaction takes place

Question 2

What are the three main methods to measure rate of reaction?

Answer 2

Change in mass
Volume of gas formed
Formation of a precipitate

Question 3

What is collision theory?

Answer 3

For a reaction to happen the reacting particles must successfully colide

Question 4

How does temperature effect the rate of reaction?

Answer 4

At a higher temperature the particles have more kinetic energy making them move faster increasing the chances of successfull collisions.

Question 5

How does concentration effect the rate of reaction?

Answer 5

At a higher pressure there are more reacting particles in the same space leading to more successfull collisions

Question 6

How does surface area affect the rate of reaction?

Answer 6

• A larger surface area provides more space for the reacting particles to collide.
• This increases the chance of successful collisions - so a faster rate of reaction.

Question 7

How does a catalyst effect the rate of reaction?

Answer 7

• A catalyst is a substance that speeds up a reaction without being used up
• By lowering the activation energy it increases the chance of successful collisions - so a faster rate of reaction.

Question 8

Rate graphs

Answer 8

• A graph is used to follow the course of reaction
• Comparing graphs show the differences in the rates of similar reactions

Question 9

What is the rate of a reaction?

Answer 9

how quickly reactants are used up or products are produced

Question 10

What is the equation for calculating the mean rate of reaction?

Answer 10

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

Question 11

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

Answer 11

g/s

Question 12

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

Answer 12

cm3/s

Question 13

What is the activation energy?

Answer 13

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

Question 14

What effect does increasing concentration have on the rate of reaction?

Answer 14

Increases

Question 15

Why does increasing concentration have this effect?

Answer 15

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

Question 16

What effect does increasing pressure have on the rate of reaction?

Answer 16

Increases

Question 17

Why does increasing pressure have this effect?

Answer 17

less space between particles means more frequent collisions

Question 18

What effect does increasing surface area have on the rate of reaction?

Answer 18

Increases

Question 19

Why does increasing surface area have this effect?

Answer 19

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

Question 20

What effect does increasing temperature have on the rate of reaction?

Answer 20

Increases

Question 21

Why does increasing temperature have this effect?

Answer 21

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

Question 22

What is a catalyst?

Answer 22

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

Question 23

How do catalysts increase the rate of a reaction?

Answer 23

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