A reaction mixture changes colour as the reaction proceeds. The light sensor reading is 100 units when the reactants are mixed.

Student 1 records the light sensor reading 30 s after mixing at two temperatures.

Temperature in $∘C^\circ\mathrm{C}$	Light sensor reading after 30 s in units
20	82
40	55

Student 2 investigates the same reaction by recording the time taken for the light sensor reading to decrease from 100 units to 40 units.

Compare the dependent variables used by Student 1 and Student 2.

Calculate the difference between the mean rates at $∘C20\,^\circ\mathrm{C}$ and $∘C40\,^\circ\mathrm{C}$ during the first 30 s.

Give your answer in light sensor units per second.

A reaction mixture changes colour as the reaction proceeds. The light sensor reading is 100 units when the reactants are mixed.

Student 1 records the light sensor reading 30 s after mixing at two temperatures.

Temperature in $∘C^\circ\mathrm{C}$	Light sensor reading after 30 s in units
20	82
40	55

Student 2 investigates the same reaction by recording the time taken for the light sensor reading to decrease from 100 units to 40 units.

Compare the dependent variables used by Student 1 and Student 2.

Calculate the difference between the mean rates at $∘C20\,^\circ\mathrm{C}$ and $∘C40\,^\circ\mathrm{C}$ during the first 30 s.

Give your answer in light sensor units per second.

8.1 Rates of reaction

8.1 Rates of reaction Questions