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| Calorimetry |
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| Calorimetry is the measurement of the
amount of heat evolved or absorbed in a chemical reaction, change of state,
or formation of a solution. |
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| We know that heat flows from a hot substance to a cold substance. In Calorimetry, a hot substance and a cold substance are mixed together. The hot substance loses heat to the cold substance until their temperatures are
equalized. |
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| According to law of conservation of energy, heat lost by the hot substance = heat gained by the cold substance. This is the principle of calorimetry. |
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| Let m1 = mass of the hot substance |
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| t1 = temperature of the hot substance |
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| m2 = mass of the cold substance |
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| t2 = temperature of the cold substance. |
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| S1 and S2 = specific heats of the hot and the cold substance respectively. |
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| t3 = common temperature reached. |
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| Heat lost by hot substance = mass x specific heat x
decrease in temperature. |
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| = m1 s1 (t1-t3) |
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| Heat gained by the cold substance = mass x specific heat x
increase in temperature |
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| = m2 s2 (t3-t2) |
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| According to the principle of calorimeter, |
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| heat lost by hot substance = heat gained by cold substance. |
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| m1 s1 (t1-t3) = m2 s2 (t3-t2) |
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| If we know the specific heat of one of the substances, by experimentally measuring all other quantities, specific heat of the given substance can be measured. |
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