Determining Heat Capacity of Water Lab Answers

Introduction

In this experiment you will measure the heat capacity of water using an electrical immersion heater.

Prediction

Throughout this experiment, we predict that the change in temperature compared to the amount of heat added to the water will be constant thus making it proportional.

Materials

• Power supply
• Immersion heater
• Connecting wire
• Thermometer
• Calorimeter
• Balance

Experiment

Temperature Chance Resulting From Energy Added to Water

Analysis

Variation Statement: E ~ T

General Equation: E = k * T

Note: K is equal to the slope of Energy vs Temperature

k = rise/run = 9000-450/46-23 = 8550/23 = 371.739

Specific Equation: E = 371.739 * T

Heat Capacity = 371.739 J/Kg/oC

Sources of Error

The capacitors suited in the power supply, may have not been functioning properly, or they were functioning poorly, thus the power supply that was directed into our water could have been even more uneven. Due to the fact that that electricity does not function in a digital system, it functions in an analog system; meaning that there is electrical noise, and thus that you will never have precision.

We were supposed to set this at 6 volts; however, we will never truly have 6 volts. We will always be >0.1 above the rated value, or below. Now accompany this by bad capacitors to filter the power, we will have some immense electrical noise. The water is tap water; it is not pure distilled water. Thus it is contaminated, and thus we cannot get a 100 percent pure result using only water.

The measurement of water added into the calorimeter was eyeballed to the best of our abilities, however, it is not exact, but an estimation. The thermometer does not record our results perfectly. We always round to get the best number possible, thus we forsake the decimal placements, which can have an impact on our precision.

Heat Capacity of 1 Kg from data collected:

Heat Capacity/Mass = 371/0.142 = 2612.676 J/Kg/oC

Additional Work

The specific heat capacity of a solid or liquid is defined as the quantity of heat required to change the temperature of a unit mass of a substance through a unit change in temperature. Our result from this experiment was somewhat close to the specific heat capacity for water, but still off the mark. We were off by 1588 J/Kg/oC from the specific heat capacity of water given in the textbook.

Our experiment could have used a digital system to reduce the amount of electrical noise and volts entering the water constantly. Another aspect of the experiment that was not perfect was the use of non-distilled water. Without the use of non-distilled water, the total heat capacity could not possibly have been measured.

Further Activity

In the world heat capacity is used on many different levels. One thing that affects most people, in Canada especially is the efficiency of their furnaces. Experts are able to find out the efficiency of our furnace thus finding the most efficient and cheapest way of warming our homes during the winter. Another application that heat capacity is commonly used is during the creation of certain types of pots and pans.

The pans must reach high levels of heat to cook the food while the handle must remain cool so that the cook will be able to hold it to put the food on plates. To achieve this, the pots must be made with something with a low heat capacity, such as aluminum, while the handles must be made with something with a high heat capacity, such as plastic.

Conclusion

Throughout this experiment, the heat capacity of water was proven to be proportional. This was proved by graphing the change in temperature and change in energy and the graph showing a straight, diagonal line showing the proportionality of heat capacity.