chemistry question

Question

Consider the reaction:

Which answer best describes the transfer of heat that occurs when 1.40 mol H2 reacts?

1. 678 kJ released
2. 339 kJ absorbed
3. 484 kJ absorbed
4. 678 kJ absorbed
5. 484 kJ released
6. 339 kJ released

Answer 1

Since 484 kJ of heat is released when 2 moles H2 react, we have the following relationship...

484 kJ/2 mole H2 x 1.4 mole H2 = 338.8 kJ of heat released when 1.4 moles H2 react.

Best answer = 339 kJ released

Answer 2

The heat of reaction is negative so this is an exothermic reaction meaning that heat is released. If we are looking at the forward reaction where H2 is reacting then the best answer is 484kJ released.