Lucius.Harrison, Enthlapy of soln, MM Lab 13 - Google Docs

Name: Lucius Harrison
SBA criteria: M/M and O/R/R
Aim: To determine the enthalpy of solution of ammonia nitrate
Apparatus and materials: Polystyrene or polythene cups, thermometer, measuring cylinder100cm3, distilled water, 8.0g sample of ammonia nitrate
1. The measuring cylinder was used to measure and pour 10cm3 of distilled water into the
polystyrene cup.
2. After waiting a few minutes the temperature measured was the initial temperature
3. The solid ammonia nitrate was added all at once to the water, it was then stirred gently to
dissolve the crystals.
4. The lowest temperature that the solution obtained was the final temperature.
Initial Temperature
Final Temperature
Treatment of results:
1. Maximum temperature change = Final temperature- Initial Temperature
2. Assuming that 1cm3 of water has a mass of 1g
Mass of solution=
3. Assuming the solution formed is dilute enough for the s.h.c. of water to be used
Specific heat capacity of water = 4.2JK-1g-1
Calculate the enthalpy change for the reaction using the formula
⩟H = m X c X ⩟ T
4. Calculate the number of the moles of ammonium nitrate in 0.8g
5. State the enthalpy change when the calculated number of moles from question 4, of
ammonium nitrate dissolves in water
6. Calculate the enthalpy change that occurs when one mole of the solid is completely
dissolved in water.
Sources of error: