Rate of reaction

Question 1

What is reaction rate?

Answer 1

The reaction rate is the number of effective collisions per unit time (e.g per second)

Question 2

What factors affect the rate of reaction?

Answer 2

Temperature
- Increases the motion of particles, increasing the rate they collide and making collisions more energetic to overcome the activation energy.
Surface area
- Increases the number of particles exposed and available to be collected with.
Concentration
- Increases number of particles per unit volume, making collisions more likely.
Use of catalyst
- Provide alternate pathways for reactions that require less activation energy or control the orientation of particles during reaction.

Question 3

What happens at the start of a reaction?

Answer 3

At the start of a reaction the rate is highest as all reactant particles are available.

Question 4

What happens in the middle of a reaction?

Answer 4

In the middle of a reaction the rate is lower as some reactant particles have been converted into product particles.

Question 5

What happens at the end of a reaction?

Answer 5

At the end of the reaction all reactant particles have been converted into products

Question 6

What two things change when concentration/surface area/temperature increase?

Answer 6

1. The initial slope of the line is steeper
   (the reaction rate is faster)
2. The line become horizontal sooner
   (the reactants are used up more quickly)
   *important - the total concentration of products produced does not change