OK, I’m stuck. Yes, it’s a homework question. I’m not asking for the answer, but where I’m going wrong in my calculations.

OK… q = mass * specific heat * ∆T (∆H = q for 1 mol.)

Given:

[ul][li]75 mL solution (25 mL added to 50 mL)[/li][li]Since density is 1.00 g/mL, mass is 75 * 1.00 = 75.00 g.[/li][li]Specific heat is 4.18 J/(g*ºC)[/li][li]∆T = 33.9 - 25.0 = 8.9ºC[/ul][/li]

So:

∆H = 75.00 g * 4.18 J/(g*ºC) * 1 kJ/1000 J * 8.9ºC = 2.79 kJ

2.8 kJ is incorrect. Negative 2.8 kJ is incorrect. Where am I screwing up?