practical 3- paper 2 and 3- kinetics/rates

Question 1

how to measure an initial rates reaction

Answer 1

investigate how the rate of reaction changes with temperature
- rate between sodium thiosulfate and hydrochloric acid can be monitored by the time taken for a fixed amount of sulfur to be produced

Question 2

reaction equation for sodium thiosulfate and hydrochloric acid

Answer 2

Na2SO3 + 2HCl–> 2 NaCl + SO2 + S + H2O

Question 3

describe an experiment to investigate the effect of temperature on the initial rate of this reaction

Answer 3

stage 1:
- use colorimeter to measure the absorbance
- add acid or thiosulfate into a colorimeter
- add second reactant and start timing

stage 2:
- repeat at different temperatures
- record time for the cross to disappear or reach a specific reading on the colorimeter
- keep the volumes and concentrations constant
stage 3:
- 1/T is a measure of rate
- plot a rate against temperature axis
- sketch a graph that curves