Required Practical 3 Effect of temperature

Question 1

How do you carry out the practical (steps 1-3)

Answer 1

1. Add 10 cm of 1 moldm-3 hydrochloric acid to the ‘acid’ tube. Place this tube into a plastic container
2. Use a measuring cylinder add 10.0 cm of 0.05 moldm-3 sodium thiosulfate solution to the second tube. Place this tube into the plastic container with the cross under it and place a thermometer in this tube.
3. Record the start temperature and then add 1 cm of the acid to the thiosulfate solution and start timing.

Question 2

How do you carry out the practical (steps 1-4-6)

Answer 2

4. Look down through the tube from above and record the time for the cross to disappear from view.
5. Record the final temperature of the reaction mixture, then pour the cloudy contents of the tube into the sodium carbonate solution.
6. Now add water from a very hot water
   to the plastic container. The water should be no hotter than 55 °C.

Question 3

How do you carry out the practical (steps 7-9)

Answer 3

7. Measure another 10.0 cm of 0.05 mol dm sodium thiosulfate solution into a clean tube. Insert this tube into the correct hole in the plastic container
8. Leave the tube to warm up for about 3 minutes.
9. Repeat steps (3) to (6) in order to obtain results for at least 5 different temperatures in total.

Question 4

What are some safety precautions that need to be taken

Answer 4

● To minimise the escape of toxic sulfur dioxide during the experiment a lid is advised.
● Wear eye protection, a lab coat and gloves as HCl is an irritant.
● Ensure that the investigation is carried out in a well-ventilated room and that appropriate measures are taken to dispose of waste solutions.