Reactions? One question.

Question

A chemist measures the energy change ΔH during the following reaction:

CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l) DeltaH: -882. kJ

Use the information to answer the following questions.

1. Is the reaction endo- or exo- thermic?
2. Suppose 24.7g of NH3 react. Will heat be released or absorbed?
3. If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed. Be sure your answer has the correct number of significant digits.

I believe the reaction is exothermic.

I believe the heat will be released.

I'm not sure how to answer "how much heat will be released on absorbed."

Answer 1

Yes, the reaction is exothermic as indicated by the negative value of ∆H

24.7 g of NH₃? There is no NH₃ in the reaction. Perhaps you meant CH₄? Assuming you meant CH₄, then the calculations would be as follows:

24.7 g CH₄ x 1 mol CH₄/16 g = 1.54 moles CH₄

1.54 moles CH₄ x -882 kJ/mol = -1362 kJ of heat released (released because it is exothermic)