chemistry question

Question

When 0.672  g of sodium metal is added to an excess of hydrochloric acid,  6990 J of heat are produced. What is the enthalpy of the reaction as written?

2Na(s) + 2HCl(aq) ⟶2NaCl(aq) +H2(g)

Answer 1

Didn't you post this identical question before? Didn't I answer it before? If you aren't happy with my original answer, please comment as to the problem so that I might address any issues you may have. It really doesn't do anyone any good for you to just post the same question over again. Here is my original answer for those who may wish to comment.

atomic mass Na = 22.99 g/mole

0.672 g Na x 1 mol Na / 22.99 g = 0.0292 moles Na

∆H = 6990 J/0.0292 moles = 239,383 J/mole = 239.4 kJ/mol Na

2Na(s) + 2HCl ==> 2NaCl(aq) + H2(g)

This reaction has 2 moles of Na being used. The enthalpy for this reaction would thus be...

2 mol Na x 239.4 kJ/mol = 478.8 kJ