Calculate the number of moles of Mg used?

Question

Mass of calorimeter 11.60g

mass of calorimeter and HCI 61.42g

mass of Mg added 0.25g

initial temperature of solution (before adding Mg) 49.39 C

Highest temperature reached after adding Mg 58.37C

How to Calculate the number of moles of Mg used. MW Mg is 24.31. round to four decimal places??

Answer 1

Moles = Mass / Mol.mass.

All the other stuff isn't required.

Mg Mass = 0.25g. Correct ?

Mg: Mol. mass = 24.31g/mol. Correct ?

Mass / Mol.mass = Moles. Correct ?

0.25g / 24.31g/mol. = 0.0103 moles Mg.

(No matter what the thumbs downer thinks. Mass CANNOT be changed, therefore moles will not change).

Answer 2

Mg + 2HCl --------> MgCl2 +  H2

You have to give us the enthalpy of reaction in the units of per kg/C