Temperature changes RPA

Question 1

what is the aim of the temperature changes RPA?

Answer 1

investigate the temperature change in exothermic neutralisation reactions?

Question 2

how do we investigate temperature change in a exothermic neutralisation reaction?

Answer 2

we add increasing hydroxide solution to acid and measure maximum temperature reached

Question 3

what is the independent variable?

Answer 3

volume of hydroxide solution

Question 4

what is the dependent variable?

Answer 4

maximum temperature

Question 5

what is the control variables?

Answer 5

volume of acid, concentration of acid and hydroxide solutions

Question 6

method of temperature changes RPA

Answer 6

1. add 30cm^3 of dilute acid to a polystyrene cup in a beaker
2. use a thermometer to record the temperature of the acid
3. add 5cm^3 of hydroxide solution and immediately attach the plastic lid so that the thermometer goes through the hole
   4.gently stir solution with thermometer
4. when the reading on the thermometer stops changing, record maximum temperature reached
5. clean all apparatuses and repeat with 10 cm^3 of hydroxide solution
6. carry out experiment several more times, each time increasing hydroxide solution volume by 5cm^3
7. repeat twice and calculate a mean for each volume of hydroxide solution

Question 7

explain the trend of the results of the temperature changes RPA

Answer 7

more hydroxide solution added means more particles react, increasing the energy released and resulting in higher temperature. Amount of energy released reaches a maximum and then stays because there is more hydroxide solution than acid and they no longer react. Temperature decreases because energy released is spread out

Question 8

why do we use a polystyrene cup

Answer 8

polystyrene is a good insulator, which removes heat lost and provides accurate results