Question

If I use 0.524g of Mg to react with 60.0mL of 1.0M H+. The density of H+ is 1.00 g/mL, and the specific heat capacity equals what water's is. The Final and Initial temp. are 65.8 and 22.

Mg(s) + 2H+(aq) ----> Mg2+(aq) + H2(g)

so to find the deltaH of this reaction .. i think i do this ...

4.184 x 60g x [65.8-22)
i'm just unsure if its 60g or some other mass i use instead ?

and how would i find the delta H of the reaction per mole of magnesium?!?!?

Answer 1

Yes, the 60 is correct. It's the solution that is absorbing the heat; therefore, the mass to use is that of the solution. What you have calculated is Joules for the reaction of 0.524 g Mg.
J/g = q/0.524. You can convert to J/mol from J/g x (atomic mass Mg/1 mol) = ??. The usual way to report data of this type is kJ/mol so you may want to convert J/mol to kJ/mol.