Practical 2- Paper 1,2,3- Topic Energetics To Measure An Enthalpy Change

Question 1

Describe how you would carry out an experiment to determine the enthalpy of solution of an anhydrous magnesium chloride

Answer 1

Stage 1
- measures water with named appropriate apparatus (volumetric pipette)
- suitable mass in the range of 100-200cm3
- intro insulated container such as polystyrene cup
- add known mass of MgCl2
- measure mass before, measure weighing boat, and calculate the difference in mass

Stage 2
- record initial temperature
- record temperature at regular timed intervals for 5+ minutes, until a trend is seen
- plot temperature vs time graph

Stage 3
- extrapolate curve back to the point of addition
- find delta T
- q=mcdeltaT
- amount=mol/mr
- delta H= Q/moles

Question 2

Improvements for the burning fuel experiment

Answer 2

• reduce the distance between the flame and the beaker
• put a sleeve around the flame to protect it from draft

Question 3

improvements for addition of solution and adding two solutions together

Answer 3

add a lid and insulate the beaker