Calorimeter Essay

A calorimeter is used to measure the quantity of thermal energy gained or lost in a chemical change. For this experiment, a “coffee cup” calorimeter (a Styrofoam cup with lids and a thermometer) was used, under constant volume and atmospheric pressure. However, this calorimeter does not retain all the heat as it is not the most optimal choice for a calorimeter, but for this experiment, it is assumed that there is no loss of heat. In relation to heat, one method is to measure the thermal energy is to measure the specific heat capacity of the substance, which is essentially the amount of thermal energy needed to heat one gram of the substance by one degree. For this experiment, by heating the metal and

The temperature of the hot metal decreases when put in the cold water, in turn increasing the water’s temperature. Therefore the heat lost from the metal must equate the heat gained by the water, assuming that no heat escaped to the surroundings or the calorimeter. The following equation displays that the heat lost from a system is negative and the heat gained is positive:

-q(metal) = q(metal)

-mmetal x cmetal x Tmetal = mwater x cwater x Twater

Since the experiment is being conducted in a calorimeter, therefore all heat lost from the metal is gained by the water, whose specific heat capacity is 4.81 J/g˚C.

The following equation shows how the molar mass of the metal can be approximated once the specific heat capacity is found: cmetal x MMmetal  25 J/mol˚C where MMmetal, is the molar mass of the metal. This estimation was proposed by Dulong and Petit, showing that one mole of all metals had roughly the same capacity to absorb heat.

The same rule applies in a neutralization reaction ; the heat evolved in the reaction in the reaction must be equal to the heat absorbed by the solution but opposite in sign. The following equation displays that