required practical - temperature change

Question 1

what does the temperature change experiment investigate

Answer 1

how to investigate the variables that effect temperature change in chemical reactions

Question 2

explain the experiment

Answer 2

1. use a measuring cylinder to measure the dilute hydrochloric acid
2. transfer this acid into a polystyrene cup which is then stood in a beaker
3. use a thermometer to measure the temperature of the acid and record
4. use a measuring cylinder to measure sodium hydroxide solution and transfer to polystyrene cup. fit a plastic lid to the cup and place thermometer through hole. use this thermometer to gently stir solution
5. because the reaction is exothermic it releases energy - the temperature of the solution will increase. look for a temperature rise on the thermometer and record when it stops ( this is the maximum temperature)
6. rinse the cup and complete the experiment again, each time increasing the amount of sodium hydroxide by 5cm cubed until 40cm cubed is reached
7. complete the WHOLE experiment again to find the mean of the results

Question 3

what are the results of the experiment

Answer 3

• as the amount of sodium hydroxide added increases so does the maximum temperature. this is the same pattern up until a certain point.
• at a certain volume, the maximum temperature begins to decrease. this is because there is so much hydroxide and not enough hydraulic acid. some sodium hydroxide is unable to react

Question 4

why use polystyrene

Answer 4

reduces any heat loss because it is a good thermal insulator