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PLEASE HELP ASAP!!!


Which statement about the following reaction is correct?

CH4 (g) + 2O2 (g) yields CO2 (g) + 2H2O(l) deltaH = -890 kJ

reacting one mole of oxygen (O2) absorbs 445 kJ of energy
reacting one mole of oxygen (O2) releases 445 kJ of energy
reacting one mole of methane (CH4) absorbs 890 kJ of energy
reacting two moles of methane (CH4) releases 890 kJ of energy

Respuesta :

1 CH4 (g) + 2 O2 (g) -----> CO2 (g) + 2H2O(l) ΔH= - 890 kJ
1 mol           2 mol
1)  If ΔH has minus, it means "release". We need only "release" choices.
2) From reaction
1 mol CH4 (g)  "releases"  ΔH= - 890 kJ  - We do not have this choice.

2 mol  O2 (g)   "release" ΔH= - 890 kJ, so
1 mol  O2 (g)   "release" ΔH= - 445 kJ
Correct answer is B.