Rate of Reaction

Question 1

What is the rate of reaction equation?

Answer 1

Change in amount of reactant/product divided by time

Question 2

What is the average rate of reaction?

Answer 2

Rate of reaction up until the reaction stops

Question 3

How do you calculate the rate of reaction at a certain time?

Answer 3

Draw a tangent on the curve at the point of measuring and equate the gradient of the tangent

Question 4

What is collision theory?

Answer 4

In order for two chemicals to react, the reactants must collide and all the collision that occur must have the activation energy

Question 5

What is concentration?

Answer 5

number of particles in a given space, higher concentration means the number of particles in that given space is greater

Question 6

What does increased concentration mean in terms of collision theory?

Answer 6

Increased rate of reaction as more collisions occur in the same period of time as particles are closer together and hence more likely to collide

Question 7

What does increased temperature mean in terms of collision theory?

Answer 7

Increased rate of reaction as:
- particles have more kinetic energy (leading to more collisions in a given period of time)
- more particles have energy equal to or greater than the activation energy
- a greater proportion of collisions end in a reaction in the same period of time.

Question 8

What is the independent and dependent variables for the required practical?

Answer 8

IV - temperature
DV - rate of reaction

Question 9

What are the control variables for the required practical?

Answer 9

CV - size of conical flask
- concentration of solutions

Question 10

What is the equipment for the required practical?

Answer 10

-measuring cylinder
-thermometer
-conical flask
-paper with x
-bunsen burner
-ice water bath
-stop clock
-beaker
-boiling tubes

Question 11

What is the method for the required practical?

Answer 11

1. Place the paper with the x under the conical flask
2. Measure out 40cm of sodium thiosulphate solution and 10 cm of Hydrochloric acid and add them to two boiling tubes
3. Place the boiling tubes in a beaker of water at a temperature, wait for the temperature to stop fluctuating.
4. Record the temperature and remove the boiling tubes
5. Add the solutions to the conical flask and start the stop clock immediately.
6. Stop the stop clock when you can no longer see the x
7. Repeat the steps 3 times at each temperature, exclude anomalies and calculate a mean
8. Use 1/mean time to work out rate of reaction
9. Plot rate of reaction to temperature graph and draw line of best fit

Question 12

What is the job of a catalyst?

Answer 12

to speed up a reaction by providing an alternative pathway for the reaction which lowers the activation energy

Question 13

What is the significance of surface area?

Answer 13

the larger the surface area, the greater the number particles available for a reaction

Question 14

What does a greater surface area and a catalyst mean in terms of collision theory?

Answer 14

More particles with the activation energy in a certain period of time and more collisions occur in the same period of time.