Both heat capacity (C) and specific heat capacity (c) deal with the amount of heat required to change a compound’s temperature by 1 Kelvin. Specific heat capacity (c) deals with changing 1 gram of a compound.
By using calorimetry we can measure the thermal energy of a reaction (system) by measuring the change in heat of the surroundings.
Concept #1: Heat capacity vs. Specific Heat Capacity
Example #1: Bomb Calorimeter
A bomb calorimeter measures the amount of calories within a substance through combustion. In other words, we “blow it up” and measure the amount of heat it releases.
If you are given energy or heat, with specific heat capacity and mass then you will most likely use q = mcΔT.
Example #2: In an experiment a 9.87 carat (1 carat = 0.200g) diamond is heated to 72.25oC and immersed in 22.08 g of water in a calorimeter. If the initial temperature of the water was 31.0oC what is the final temperature of the water? (cdiamond = 0.519) (cwater = 4.184 ).
Practice: A sample of copper absorbs 35.3 kJ of heat, which increases the temperature by 25 degrees Celsius, determine the mass (in kg) of the copper sample if the specific heat capacity of copper is 0.385 J/g *C.
When dealing with heat it is important to remember that if one compound is gaining heat that means another compound is losing heat.
Practice: 50.00 g of heated metal ore is placed into an insulated beaker containing 822.5 g of water. Once the metal heats up the final temperature of the water is 32.08 degrees Celsius. If the metal gains 14.55 kJ of energy, what is the initial temperature of the water?
The enthalpy or heat of a reaction can be calculated through the use of a coffee cup calorimeter.
Concept #2: Coffee Cup Calorimeter
Concept #3: Calculating the Heat of the Solution
The heat of the solution can be determined by first determining the heat of water.
Concept #4: Calculating the enthalpy of the reaction