Energetics

Question 1

Which is the activation energy in an energetic graph?

Answer 1

The difference from the centre line and the highest point in the graph

Question 2

What is the enthalpy change in an energetic graph

Answer 2

The difference from the centre line to the finished products

Question 3

In an energetics graph, why does the line rise then sink

Answer 3

Energy is taken from the surroundings to break bonds (rise)

Energy is released from making new bonds (drop)

Question 4

What is calorimetry?

Answer 4

Determining the enthalpy change of a combustion reaction

Question 5

What 4 things do we need to know for calorimetry?

Answer 5

1. Mass of fuel
2. Mass of water
3. Specific heat capacity of water
4. Change in temperature

Question 6

What is the equation for energy change?

Answer 6

Q=CMtriangleT

Energy change = SHC of water x mass of water x temperature change

Question 7

What is specific heat?

Answer 7

The amount of heat per unit mass required to raise the temperature by one degrees c

Question 8

How do you calculate molar enthalpy changes?

Answer 8

1. Calculate the amount of energy transferred (calorimetry)