Specific Heat of Solids

Specific Heat of Solids

I. Objective

The objective of the study is to explain, measure and better understand the specific heat of copper and lead using the method of mixtures.

II. Theory

Heat is a form of energy it is either expressed in joules, calories, or kilo-calories According to the law formulated by the French chemists Pierre Louis Dulong and Alexis Thérèse Petit, the specific heat of solids which is characterized as the amount of heat required to raise the temperature of one gram of a substance to one degree Celsius specimens are inversely proportional to their atomic weights; that is, the specific heat multiplied by the atomic weight is approximately a constant quantity for all the solid elements. (http://encarta.msn.com). The heat capacity C of an object is defined as c= Q/m?T, where Q is the amount of heat required to change the temperature of the object by T. The specific heat c of a substance is the heat capacity per unit mass. The specific heat is measured in J/kgoC or cal/goC or kcal/kgoC. Suppose we have two objects, one hot and one cold. Let m1 and m2 be the masses of the hot and cold objects,T1 and T2 be the temperatures of the hot and cold objects, and c1 and c2 be their specific heats respectively. These two objects are brought into thermal contact with each other and allowed to reach a common final equilibrium temperature T3. We are assuming the system to be thermally insulated from the surroundings. According to conservation of energy, the heat gained by the cold object would equal the heat lost by the hot object.

?Qgained = ?Qlost;

Or

m2c2 (T3 - T2) =m1c1 (T1 ? T3)

For this experiment, consider your system to consist of mixing a given mass m1 of a ?hot" specimen with specific heat c1 at te...

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...easurement.

VIII. Conclusion

In conclusion, I can say that the method of mixtures is a simple but an effective way to compute for the specific heat of specimens. In addition, the experiment helped clarify the concept of specific heat. I have learned that the specific heat is the amount of heat required by an object for it to change its temperature by a certain amount usually by one degree. This was shown when the specimens were transferred from one container to another that differed in temperature.

IX. Answer to questions

1. The thermometer also gains some of the heat. Neglecting the heat capacity of the thermometer, it causes inaccuracy in the measurement of specific heat.

4. given:

Ms = 50 g

T1 = 100 C

Mw = 200 g

T2 = 20 C

Cc = 0.092

Mc = 100

T3 = 22

Cs = ((200)(1)+(100)(0.092))(22-20))

50(100-22)

Cs = 0.107 cal/gCo