Measuring the Enthalpy Change of A Reaction

To determine the enthalpy change of the reaction the heat given out or taken in as the reaction proceeds is calculated by using the specific heat capacity of water.The specific heat capacity of water is the amount of energy needed to heat 1g of water by 1K and is 4.18 joules per gram per kelvin. This means it takes 4.18 joules of energy to heat one gram of water so its temperature rises by 1K.The heat given out or taken in from the surroundings in a reaction can be used to raise the temperature of a known mass of water. The heat given out or taken in can be calculated from the formula:Q = m c ΔTwhere Q is the heat energy transferred in joules, m is the mass of water in grams, ΔT is the change in temperature and c is the specific heat capacity of water which can be rounded up to 4.2Jg^-1K^-1. The enthalpy change is found by dividing Q by the number of moles reacting, and is negative if heat is given out.