How to Find the Specific Heat of a Metal
The amount of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius is known as the specific heat capacity. It is usually expressed in units of Joules per grams per degree Celsius or calories per gram per degree Celsius. Scientists have developed a method known as calorimetry to determine the specific heat of any substance. The process usually involves heating the substance then placing it in cool water. Heat transferred to the sample can be determined by using the value of heat transferred to the water from the metal.
Instructions
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1
Consider weighing about 20 grams of the unknown metal and place the metal in a large test tube. Use grams as units of measurement. Take an empty cup and record its mass. Fill it with about 4.5 ounces of distilled water and take another weight measurement. Record the mass as “Mass of water plus mass of cup”.
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2
You will be required to determine the mass of water inside the cup. This can be done by subtracting the mass of the empty cup from the mass of the cup plus mass of water. So, if the mass of the cup is 5 grams and mass of water plus mass of cup is 80 grams, then mass of water can be calculated very easily;
80-5 = 75 grams. -
3
Temperature change can be calculated by subtracting the initial water temperature from the final temperature Tf. For example, if the initial water temperature reading was 25 degree Celsius and the final temperature reading is 45 degree Celsius, then change in temperature will be;
Change in temperature: 45-25 = 20 degree Celsius -
4
Multiply the change in temperature with the metal’s mass. So if mass of the metal is 300 grams; then the answer will be 25 x 300 = 7500 grams degree Celsius. Heat transferred to the water can be determined by multiplying the change in temperature with water mass and its specific heat value. According to the second law of thermodynamics, heat lost by one body should be equal to the heat gained by the other body. Therefore, heat gained by the water will be the same as heat lost by the metal.
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5
Dividing the heat necessary to achieve the temperature change by heat supplied to the substance. So if the metal absorbed 2000 Joules, then the answer will be 2000/7500 = 0.26 Joule/grams degree Celsius. This is metal’s specific heat value.
