a) Coffee Cup Calorimeter
Most reactions we perform in chemistry 30 are done in solution. The cheapest and most effective calorimeter to use to study solution chemists is a simple Styrofoam coffee cup. Water and the Styrofoam are the surroundings and the Styrofoam provides adequate insulation since most reactions in solution occur relatively rapidly. A thermometer is used to measure the temperature change in the water solution. Water is typically used because of it's high specific heat capacity, which means it can store large amounts of heat without large temperature changes occurring. (It can also release large amounts of heat for the same reason). Other substances , like oil can be used in place of the water.
The coffee cups may be nested (placed one inside another) to provide addition insulation if needed. A picture of a nested coffee cup calorimeter is seen below.
| Coffee Cup Calorimeter |
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b) Bomb (Constant Volume) Calorimeter
Some reactions, like combustion's can't be performed in solution. In order to determine the molar enthalpies of these reactions chemists create reaction chambers called bombs in which the reacting mixtures are allowed to combine. The products of the combustion are not allowed to escape. These are therefore often called constant volume calorimeters. The bomb is made of a material that readily transports heat to the surroundings (for example copper), and is strong enough to withstand the pressures of the reactions. The bomb is then surrounded by a substance that will absorb, or release the heat involved in the reaction, usually water.
c) Flame Calorimeters
Less efficient and expensive flame calorimeters can be used, that may simply consist of a tin can fill with water that is exposed to the heat of combustion. A simple apparatus is shown below.
| Flame Calorimeter |
Labs and Activities on Calorimetry
Complete the following activities to become familiar with the Calorimetry technique.
 | Laboratories Coffee Cup Calorimetry #1 Measuring the molar enthalpy of dissolving of ionic solids #2 Measuring the molar heat of fusion of ice. |
 click | Inquiry: Heat of Combustion click on the question mark and complete the lab |
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