To use Hess' law to find the hydration enthalpy of MgSO4
Hydration enthalpy can be defined as the energy change when 1 mole of
an anyhydrous salt forms 1 mole of a hydrated salt:
MgSO4 + 7H2O
- Measure approximately 50ml of water into a weighed polystyrene cup.
- Record the temperature over 1 minute to ensure stability.
- Add approximately 5 g of anhydrous magnesium sulphate (you must know
the mass exactly)
- Stir to dissolve noting the highest temperature reached.
- Repeat the procedure using hydrated magnesium sulphate in place of
anhydrous magnesium sulphate.
The following factors must be considered:
- Accurate recording of raw data
- Choice of suitable apparatus and method
- Presentation of raw data
- Data analysis and presentation
- Evaluation of errors both qualitative and numerical
Assessment suitable for: