Question

17. Calculate H for the following reaction using Hess law

H2 (g) + Br2 (g) → 2 HBr (g)

Experimental information

2 H+ → H2 H -436.4 kJ

2 Br- → Br2 H -192.5 kJ

2 H+ + 2 Br- →2 HBr H -144.8 kJ

Answer 1

There is something inherently wrong with these equations. That's the major reason I didn't answer when you had this posted a few days ago.
You simply can't get H2 from 2 H^+ and you can't get Br2 from 2Br^-
IF you could get two H^+ to combine (and I doubt that will ever happen) you would have H2^2+ Same scenario with Br^- + Br^-.