# Measuring the Specific Heat of a Metal

## Purpose:

• to determine the specific heat of brass (or other metal)

## Discussion:

Suppose you place a hot piece of metal into some room-temperature water. Heat will flow from the hot metal into the cool water until thermal equilibrium is reached. If no energy escapes from the water-metal system, the heat energy lost by the metal will equal the heat gained by the water. Since we know that heat energy is related to temperature change by:

you can calculate the specific heat of the metal.

## Equipment:

 calorimeter thermometer brass weight (or other metal object) string water graduated cylinder or beaker

## Safety Notes:

1. The water bath will be VERY HOT! Do not reach into it!
2. Be sure to handle the brass weight by the attached string - the brass weight will be HOT! DON'T TOUCH!
3. Do NOT stir the calorimeter with the thermometer!
4. If the thermometer breaks, report it to your instructor immediately. DO NOT attempt to clean up the broken glass yourself.

## Procedure:

1. Construct a data table. You will need to record the mass and starting temperature of the water in the calorimeter, the mass and starting temperature of the brass weight, and the final equilibrium temperature of the water and metal.
2. Measure about 200 ml (= 200 grams) of water into your calorimeter cup. Carefully measure the water's temperature and record it in your data table.
3. Measure and record the temperature of the hot-water bath that your teacher has set up, which contains the brass weights. Since the weights have been immersed in this bath for a long time, you can assume that the temperature of the brass weight equals the temperature of the water bath.
4. Place one of the brass weights into your calorimeter cup and close the top. Record the mass of the metal in your data table.
5. When it appears that the metal-water system has reached thermal equilibrium, record the final temperature in your data table.
6. If you have time, run another trial - you never have too much data.

## Results:

1. Calculate the specific heat of brass. (See Ch 21 Think & Solve Question #4 (p. 324) for an example) Show your calculation.
2. Look up a published value for the specific heat of brass (Handbook of Chemistry & Physics).
3. Calculate the percent of difference between your calculated value and the published value. Show your calculation.

## Conclusions:

How well does your value of specific heat compare to the published value? How do you account for any differences? If you were going to repeat this lab, what could you do to improve your results?

last update March 4, 2004 by JL Stanbrough