Rates Of Reaction

Question 1

The rate of chemical reaction

Answer 1

How fast the reactants are changed into products.

Question 2

Slow reactions

Answer 2

• rusting of iron

- chemical weathering-acid rains damage to limestone buildings

Question 3

Moderate reactions

Answer 3

Magnesium with acid

Question 4

Fast reactions

Answer 4

• burning

- explosion

Question 5

Factors affecting rates of reaction

Answer 5

• temperature
• concentration of the solution or the pressure of gas
• surface area
• use of catalyst

Question 6

The rate of reaction depends…

Answer 6

On the frequency of successful collisions.

Question 7

Temperature increases the rate

Answer 7

Particles move faster, they are going to collide more frequently

Question 8

A formula for a rate of reaction (reactant)

Answer 8

rate = amount of reactant / time

Question 9

A formula for a rate of reaction (product)

Answer 9

rate = amount of product / time

Question 10

The steeper the gradient of a line on the graph is…

Answer 10

the faster the reaction is.

Question 11

How can you measure the rate of reaction in experiments?

Answer 11

• measuring the decreasing mass of a reaction mixture
• measuring the increasing volume of gas given off
• measuring the decreasing light passing through a solution( decrease is caused by precipitate)

Question 12

Collision theory

Answer 12

Chemical reactions can only occur when reacting particles collide with each other and with sufficient amount of energy.

Question 13

Activation energy

Answer 13

The minimum amount of energy that particles must have to react.

Question 14

Increasing pressure of a gas or concentration of a solution

Answer 14

Increase the

Question 15

Reactions are rapid, initially…

Answer 15

because we have a large number of reactant molecules. So we have a large number of collision per second.

Question 16

Over time reactions…

Answer 16

slow down because the number of reactant molecules is running out. So smaller number of collisions per second.

Question 17

The reaction stops when…

Answer 17

all the reactant molecules have run out, so the number of collisions per second is 0.

Question 18

How does concentration/ pressure affect the rate?

Answer 18

The higher the concentration or pressure, the more reactant particles are available and so the frequency of successful collision is higher.

Question 19

How does surface area affect the rate?

Answer 19

The greater the surface area, the more particles can react with the solution/gas, so the frequency of collisions increases. The solution cannot react with particles which are not on the surface.