Question

Based on the enthalpy changes given for the reactions, which reactions are endothermic? (check all that apply)

2H2O → 2H2 + O2, ΔH = 484 kJ

C + O2 → CO2, ΔH = -394

kJ H2 + Br2 → 2HBr, ΔH = -73

kJ 2NH3 → N2 + 3H2, ΔH = 92 kJ

Answer 1

Based on the given bond energies, what is the enthalpy change for the chemical reaction?

A.

-352 kJ

B.

-210 kJ

C.

-176 kJ

D.

-105 kJ

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Step-by-step explanation:

Answer 2

In an endothermic reaction, “delta H” is always positive, since the system is absorbing heat from its surroundings, not releasing into the surroundings like in an exothermic reaction where the delta H is always negative.

So our endothermic reactions would be the first (484kJ) and the last (92kJ).