CHEM 1011
Calorimetry: The Determination of the Specific Heat of a Metal
Calorimetry
• Calorimetry – the science of measuring heat transfer.
Calorimetry
• Principle of Conservation of Energy-
Energy can neither be created nor destroyed in any process, but can be transferred from one part of a system to another
Calorimetry
• Calorimeter – device used to measure heat – calorimeter cup and thermometer.
Calorimetry
• Specific heat – the amount of heat needed to raise temperature of 1 g of a substance 1° C.
• Specific heat is an intensive property.
Calorimetry
• Specific heat values are generally lower for metals and higher for non-metals
(see Table 9.1).
Calorimetry• When a given mass of a substance
undergoes a temperature change, the equation showing the relationship between quantity of heat, specific heat, mass, and temperature change is
Q = SH x m x ΔT
ΔT = Tfinal - Tinitial
Calorimetry
• Heat lost by one substance is equal to the heat gained by the other.
Qlost = Qgained
Conclusions and Calculations
Heat Capacity of the Calorimeter
• Because calorimeter absorbs heat, must calculate Ccal.
Heat Capacity of the Calorimeter
• Construct graph and extrapolate maximum temperature.
Heat Capacity of the Calorimeter
ΔT of cold water and calorimeter = (5) – (3)
Heat Capacity of the Calorimeter
ΔT of warm water = (5) – (4)
Heat Capacity of the Calorimeter
Heat lost by warm water = (2) x 1.00cal/gºC x (7)
Heat Capacity of the Calorimeter
Heat gained by cold water & calorimeter = - (8)
Heat Capacity of the Calorimeter
Heat gained by cold water = (1) x 1.00cal/gºC x (6)
Heat Capacity of the Calorimeter
Heat gained by the calorimeter = (9) – (10)
Heat Capacity of the Calorimeter
Heat capacity of calorimeter, Ccal = (11) / (6)
Specific Heat of a Metal
Mass of metal = (3) – (2)
Specific Heat of a Metal
• Construct graph and extrapolate maximum temperature.
Specific Heat of a Metal
ΔT of cold water and calorimeter = (7) – (5)
Specific Heat of a Metal
Heat gained by calorimeter and water =
[(1) x 1.00cal/gºC x (8)] + [Ccal x (8)]
Specific Heat of a Metal
ΔT of the metal = (7) – (6)
Specific Heat of a Metal
Heat lost by the metal = - (9)
Specific Heat of a Metal
Specific heat of the metal = (11) / [(4) x (10)]
Specific Heat of a Metal
• According to the Law of Dulong and Petit,
SHmetal x gram atomic mass = 6.3 cal/moleºC
• Rearranged, it becomes
gram atomic mass = 6.3 cal/moleºC / SHmetal
Specific Heat of a Metal
Atomic mass = 6.3 cal/moleºC / (12)