[jsmith613]

in class we carried out an enthalpy change reaction using 1g of Calcium and 100cm3 of (excess) HCl (aq).

We worked out the moles of Calcium as x, moles of (excess) HCl as y and moles of HCl required to react as z.

We reacted the two and calculate the energy transferred in kJ, ValE.

We then had to calculate kJ/mol by dividing ValE / x

But we saw x was the value of moles for Calcium.

Surely if we are calculating enthalpy change / mol we would calculate the enthalpy change of the solution so we should us y or z but we did not

please explain why

thanks

[jsmith613]

as a question, does it have anything to do with the fact that the HCl (aq) is in excess?