Paper 1 - Energetics

Question 1

Describe the simple calorimetry experiment: combustion

Answer 1

1. Fixed volume of water is measured and transferred to a copper can
2. The spirit burner, containing fuel, is weighed on a 2d.p. balance
3. Initial temperature of water is measured and recorded
4. Alcohol ignited and water stirred continuously
5. When the temperature has risen to approximately 50°C, flame is extinguished and spirit burner is re-weighed
6. Final temperature of water recorded

Question 2

What is the equation for heat energy change?

Answer 2

Q=mc∆T

Question 3

What is an exothermic reaction?

Answer 3

A chemical reaction in which heat energy is transferred to the surroundings

Question 4

What is an endothermic reaction?

Answer 4

A chemical reaction in which heat energy is absorbed from the surroundings

Question 5

What kind of reaction is displacement?

Answer 5

exothermic or endothermic

Question 6

What kind of reaction is dissolving?

Answer 6

Salts dissolving in water can be either exothermic or endothermic

Question 7

Describe the simple calorimetry experiment: neutralisation

Answer 7

• Put 25cm^3 of hydrochloric acid and sodium hydroxide in separate beakers
• Place the beakers in a water bath set to 25℃ until both beakers reach 25℃
• Add the HCl followed by the NaOH to a polystyrene cup with a lid
• Take the temperature of the mixture every 30 seconds, and record the highest temperature

Question 8

Describe the simple calorimetry experiment: displacement

Answer 8

• 50 cm3 of copper(II) sulfate is measured and transferred into a polystyrene cup.
• The initial temperature of the copper sulfate solution is measured and recorded.
• 5g of Magnesium is added and the maximum temperature is measured and recorded.
• The temperature rise is then calculated.