Specific Heat Capacity of Ethanol Lab

Background Information:

The heat capacity of the entire calorimeter system (C) is the sum of the heat capacities of the calorimeter (Ccal) and all of the substances in the calorimeter. Although water is the most frequently used liquid, it is possible to employ a liquid other than water in the calorimeter. In this example, suppose the calorimeter contains ethanol. The heat capacity of the entire calorimeter system is thus

C = Ccal + CEtOH

The heat capacity of the ethanol (CEtOH) depends upon how much ethanol is in the system.It is therefore more convenient to replace CEtOH with the specific heat capacity of ethanol (sEtOH) and the mass of ethanol (mEtOH).

C = Ccal + sEtOH mEtOH

Experimentally one knows the mass of ethanol used in the experiment, and one can measure the heat capacity of the entire calorimeter system. This leaves two unknowns, Ccal and sEtOH, in the above equation.

One approach to determining these values is to perform two experiments using two different masses of ethanol. Two equations involving Ccal and sEtOH may then be written. The simultaneous solution of these two equations yields values for Ccal and sEtOH.

A superior strategy for determining Ccal and sEtOH is to make a series of measurements of C at varying values of mEtOH. A plot of C vs mEtOH will yield of straight line with a slope ofsEtOH and an intercept of Ccal. This approach has the advantage of using multiple measurements to obtain "average" values of Ccal and sEtOH to reduce the experimental error. In addition, the linearity of the plot is a good diagnostic tool for checking the integrity of both the data and the theory used to generate the working equation.

Major Goals:-Finding the specific heat capacity of Ethanol by using the heat formula to solve for it.-Gain a better understanding of specific heat capacity and what it is-Observe temperature equilibrium and understand the Law of Conservation of Energy

Procedure: 1. Heat 400 mL of water in a 500 mL beaker.2. Place the test tube into a free beaker onto a scale and “zero out” the mass. 3. Using a pipet, pour 20 ml of ethanol into the test tube until the mass reaches about

10 grams and record mass.4. Use a utility clamp and suspend the test tube into the boiling water. The level of

the ethanol should be placed under the boiling water in the beaker. Constantly

read the temperature of the ethanol and stop heating process once it reaches 78.4°C, which is approximately 5 minutes in the boiling water.

5. Measure the temperature of the ethanol and record onto the data table. 6. Using the graduated cylinder measure a 200 mL of water and pour into the

calorimeter. Measure the temperature of the calorimeter of the water and record along with the 200 mL of water.

7. Remove the test tube from the boiling water and pour the ethanol into the calorimeter. Be sure to pour the ethanol into the calorimeter and close the lid.

8. Stir the contents in the calorimeter and record the maximum temperature it reaches.

9. Clean up.

Data Table:Mass of Boiling Water 400 mLMass of Ethanol 20gTemperature of EthanolVolume of Water in Calorimeter 200 mLTemperature of Water in CalorimeterFinal/Maximum Temperature in Calorimeter (w/ Ethanol)