Factors effecting rates of reaction

Question 1

What four things do the rate of reaction depend on ?

Answer 1

1. Temperature
2. The concentration of a solution or the pressure of gas.
3. Surface area- this changes depending on the size of the lumps of a solid.
4. The presence of a catalyst.

Question 2

How do all four methods help speed up the rate of reaction?

Answer 2

They increase the number of successful collisions between the reacting particles.

Question 3

How does increasing the temperature, increase the rate of reaction ?

Answer 3

1. When the temperature is increase, the particles all move faster.
2. If they’re moving faster, they’re going to collide more frequently.
3. Also the faster they move the more energy they have, so more of the collisions will have enough energy to make the reaction happen.

Question 4

How does increasing the concentration of pressure,
increase the rate of reaction?

Answer 4

1. If u have a more concentrated solution, it means there are more particles knocking about in the same volume of water ( or other solvent )
2. When the pressure of gas is increased, it means that the same number of particles occupies a smaller space.This makes collision between the reactant particles more frequent.

Question 5

How does increasing the surface area, increase the rate of reaction ?

Answer 5

1. If one of the reactants ins a solid, then breaking it up into smaller pieces will increase its surface area to volume ratio.
2. This means that for the same volume of solid. the particles around it will have more are to work on- so there will be collisions more frequently.

Question 6

How does using a catalyst, increase the rate of reaction ?

Answer 6

1. A catalyst is a substance that speed up a reaction, without being used up in the reaction itself. This means it’s not part of the overall reaction equation
2. Different catalysts are needed for different reactions, but they all work by decreasing the activation energy needed for the reaction to occur. They do this by providing an alternative reaction pathway with a lower activation energy.
3. Enzymes are biological catalysts- they catalyse reactions in living things.