Determine the Enthalpy Change During the Interaction (Hydrogen Bond Formation) Between Acetone and Chloroform
When acetone is mixed with chloroform, heat is evolved due to formation of hydrogen bonds between chloroform and acetone :
Heat evolved during this interaction can be determined experimentally by mixing the two liquids and measuring the heat change by using a calorimeter.
(a) Apparatus. A wide mouthed polythene bottle fitted with a thermometer ( 1/10 th degree) and a stirrer (to serve as calorimeter), 100 ml measuring cylinder.
(b) Chemicals. Pure acetone and pure chloroform.
A. Determination of Calorimeter Constant
- Put 100 ml of distilled water in polythene bottle with a thermometer and stirrer Fig.
- Note the temperature (t1°C).
- Heat some water in a beaker to a temperature 20-30°C higher than that of room temperature.
- Put 100 ml of this warm water in another beaker.
- Note the temperature of this water. Let it be t2°C.
- Add warm water from the beaker into the polythene bottle without any loss of time.
- Stir the contents.
- Read the temperature attained after mixing. Let it be t3°C.
B. Determination of Enthalpy of Interaction of Acetone and Chloroform
- Take a clean and dry polythene bottle calorimeter.
- Place 100 ml acetone in it.
- Note the temperature of acetone.
- Take 100 ml of chloroform in a beaker and note its temperature. Both the solutions should have same temperature otherwise wait for sometime so that they attain same temperature.
- Transfer the chloroform into the calorimeter and immediately fit the cork (or lid) having thermometer and stirrer. Stir gently.
- Note the temperature after small intervals till it becomes constant.
- Record the highest temperature reached.
Enthalpy change during mixing of 100 ml of acetone with 100 ml of chloroform = – X Joules.