[sallylam0510]

2 Fe(s) + 6 HCl(aq)  2 FeCl3(aq) + 3 H2(g)
Note that since that reaction occur in aqueous solution,it is resonable to substitute the specific heat capacity of water=4.184J/gC)

Q1. When 1.123 grams of iron metal are mixed with 26.243 grams of hydrochloric acid in a coffee cup calorimeter, the temperature rises from 20.8°C to a maximum of 31.0°C. Use this experimental data (not the table in your book) to determine the change in heat for the reaction in joules (J).
My answer: q=mc(change of T)
=(1.123+26.243g)(4.184J/g C)(31.0C-20.8C)
=1167.8933J
=1.17J(3 sig fig)
Is it correct?

Q2.Determine the experimental value of H for this reaction in units of kJ/mol of iron.
My answer: 1167.89J(1KJ/1000J)(1/0.02011mol)*2
=116.151KJ/mol
=116KJ/mol (3sig fig)

Can someone teach me how to do it?

[Borek]

q=mc(change of T)
=(1.123+26.243g)(4.184J/g C)(31.0C-20.8C)
=1167.8933J
=1.17J(3 sig fig)

I guess you meant 1.17 kJ. Principle looks OK, haven't checked the numbers. I am not sure about a sign, question is a little bit ambiguous to me. I would accept the answer, your teacher may not - hard to say.

1167.89J(1KJ/1000J)(1/0.02011mol)*2
=116.151KJ/mol
=116KJ/mol (3sig fig)

Why do you multiply by two? I guess to take care of stoichiometric coefficient? That would give answer per so called "mole of reaction", not mole of iron.

And think about sign - this reaction is exothermic.