posted by Tim .
1) Determine the amount of heat in kJ given off when 1.26 x 10^4 g of NO2 are produced according to the equation:
2NO (g) + O2 (g) --> 2NO2 (g)
and delta (H) = 483.6 kJ/mol
2) A sheet of gold weighing 10 g and at a temperature of 18 degrees C is placed on a flat sheet of iron weighing 20 g and at a temperature of 55.6 degrees C. What is the final temperature of the combined metals? (Assume that no heat is lost to the surroundings and the heat gained by the gold must equal the heat lost by the iron.)
The data you gave for #1 shows delta H as +483.6 and that makes it an endothermic reaction so there will be no heat given off. You may want to re-reread/re-type the question.
2. heat lost by Fe + heat gained by Au = 0
(mass Fe x specific heat Fe x (Tfinal-Tinitial) + (mass Au x specific heat Au x (Tfinal-Tinitial) = 0
Substitute the numbers and solve for Tf. That's the onlyh unknown.