measuring rate of reaction

• method:

  1. add 50cm of 8g/cm sodium thiosulfate solution to conical flask
  2. place conical flask on piece of paper with black cross drawn on it
  3. use different measuring cylinder and add 10cm of dilute hydrochloric acid to conical flask
  4. swirl flask immediately and start stopwatch
  5. when cross can no longer be seen, stop timer on stopwatch
  6. repeat using different starting concentrations of sodium thiosulfate solution