Measuring the Enthalpy Change

Question 1

calorimetry (polystrene cup method)

Answer 1

1) washes the equipment (cup and pipettes etc) with the solutions to be used

2) dry the cup after washing

3) put polystyrene cup in a glass beaker for insulation and support

4) Measure out desired volumes of solutions with volumetric pipettes and transfer to
insulated cup
clamp thermometer into place making sure the thermometer bulb is immersed in
solution

5) measure the initial temperatures of the solution or both solutions if 2 are used

6) Do this
every minute for 2-3 minutes

7) stirs mixture (ensures that all of the solution is at the same temperature)

8) Record temperature every minute after addition for several minutes

Question 2

Error with this method

Answer 2

1) reaction or dissolving may be incomplete or slow
2) Density of solution is taken to be the same as water
3) heat loss to the surroundings

Question 3

Flame Calorimetry method

Answer 3

1) fuel is burnt and the flame is used to heat up water in a metal cup.

Question 4

errors of flame calor

Answer 4

1) incomplete combustion of fuel
2 Incomplete transfer of energy
3) Evaporation of fuel after weighing