Chemical Energy

Question 1

Enthalpy change (ΔH)

Answer 1

cmΔt

Question 2

What measurements must be taken to find the enthalpy of combustion

Answer 2

the starting temperature of the water
the final temperature of the water
the mass of the burner before the experiment
the mass of the burner after heating
the temperature change

Question 3

The enthalpy of combustion of a substance is defined as

Answer 3

the heat energy given out when one mole of a substance burns completely in oxygen

Question 4

Combustion reactions are exothermic so the value for the enthalpy change (ΔH) is always

Answer 4

Negative

Question 5

Hess’s Law states that

Answer 5

the enthalpy change for the overall process will be identical regardless of how many steps are take