Question

Zinc metal reacts with hydrochloric acid according to the following balanced equation.

Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g)

When 0.114 g of Zn(s) is combined with enough HCl to make 51.1 mL of solution in a coffee-cup calorimeter, all of the zinc reacts, raising the temperature of the solution from 22.5 degrees Celsius to 24.7 degrees Celsius .

Find Delta Hrxn for this reaction as written. (Use 1.0 g/mL for the density of the solution and 4.18 J/g*C as the specific heat capacity.)

Delta Hrxn =.........KJ

Answer 1

q = mass x specific heat x delta T.
That gives you q for 0.114 g Zn which I call delta H rxn (as it was run).
You can do q/0.114 if you want delta H in joules/g and that x 65.39 if you want delta H in joules/mole.

Answer 2

34.98