Looking back at the calorimeters above, when chemicals react and give off/take in energy, we can use calculations to work out exactly how much energy has changed. There is one vital piece of information we need to know to do this:
4.2 joules of energy raises 1g of water by 1°C
Hence the units involved in this energy change will be kJ/g/°C (kilojoules per gram per degree). A simple calorimeter is used to measure energy change in a reaction A + B → C. So let’s calculate an example of such a reaction:
Question : 60cm³ of a solution containing 0.1 moles of A is mixed with 40cm³ of a solution containing 0.1 moles of B. Prior to mixing, their temperature was 19,6°C. After mixing, the maximum temperature reached was 26.1°C.
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