Stepwise calculation of enthalpy of combustion from experimental data

Step 1:Calculate the energy change used to heat the water. Q = m x cp x ΔT. Note that the mass is the mass of water in the calorimeter and not the alcohol

Step 2: Calculate the number of moles of the substance combusted.

step 3: calculate the enthalpy change per mole, which is called ΔcH (the enthalpy change of combustion)

final step: Finally, add in the sign to represent the energy change: if the temperature increases, the reaction is exothermic and is given a minus sign, and vice versa, it is true for an endothermic reaction

The enthalpies of combustion can be calculated by using calorimetry. Generally, the fuel is burned, and the flame is used to heat water in a metal cup.

example: Calculate the enthalpy change of combustion for the reaction where 0.650g of propan-1-ol was completely combusted and used to heat 150g of water from 20.1 to 45.5 °C.

Begin by Calculating the energy change used to heat the water using the equation Q = m x cp x ΔT

calculate the number of moles of alcohol combusted. Use the mole calculation concept. moles is mass divided by the molar mass

Calculate the enthalpy change per mole by taking the enthalpy obtained in step 1 and dividing by the moles obtained in step 3.

Finally, add in the sign to represent the energy change: if temperature increases, the reaction is exothermic and is given a minus sign

That is how simple it is. I hope its helpful