RPA 5 Rate Of Reaction

Question 1

Method

Answer 1

• measuring cylinder to put 10cm of sodium thiosulphate solution into a conical flask
• place on printed cross
• add 10cm of hydrochloric acid into conical flask
• swirl solution and start stopwatch
• look down into flask
• stop clock when no longer see cross
• repeat but with lower concentrations
• repeat and find mean

Question 2

Problem with the experiment

Answer 2

People have different eyesights
= some people see cross for longer

Question 3

How is problem prevented

Answer 3

By using the same size cross

Question 4

How to measure volume of gas

Answer 4

• use measuring cylinder and put 50cm of hydrochloric acid into a conical flask
• attach conical flask to bung and delivery tube
• place delivery tube into container filled with water
• place upturned measuring cylinder
• add 3cm of magnesium to hydrochloric acid and start stopwatch
• produces hydrogen gas trapped in cylinder