3(a) Energetics

Question 1

Exothermic Reactions

Answer 1

Chemical reactions in which heat energy is released to the surroundings

Question 2

Endothermic Reactions

Answer 2

Chemical reactions in which heat energy is taken in from the surroundings

Question 3

Calorimetry Experiments: Combustion

Answer 3

1. Add cold water to copper can
2. Measure initial temp. of water
3. Weigh ethanol spirit burner with lif
4. Light wick
5. Heat till water reaches 40 degrees celsius
6. Put lid on spirit burner to extinguish flame
7. Stir water and measure final temp. of water
8. Reweigh spirit burner with lif
9. Work out mass of alcohol burnt

moles = mass/mr

Question 4

Calorimetry Experiments: Displacement

Answer 4

1. Add copper sulfate solution to polystyrene cup
2. Add zinc
3. Stir solution
4. Record max temp. reached

moles = vol x conc

Question 5

Calorimetry Experiments: Neutralisation

Answer 5

1. Fill burette with acid
2. Put alkali in polystyrene cup
3. Add acid 5cm3 at a time until 50 cm3 has been added

H+ OH- -> H2O

Question 6

Is bond breaking exo or endo?

Answer 6

Endo

Question 7

Is bond making exo or endo?

Answer 7

Exo

Question 8

Delta H

Answer 8

Bonds broken - bonds made