Question

Which of the following reactions represents an exothermic reaction?

NH3(g) + 12.0 kcal → ½N2(g) + 3/2H2(g)
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal
C + 2S → CS2, ΔH = 27,550 cal
C(graphite) → C(diamond), ΔH = 0.45 kcal
2H2O → 2H2 + O2, ΔH = +58 kcal

Answer 1

CH₄ + 2O₂ → CO₂ + 2H₂O + 212,800 cal
The combustion reaction of methane is an exothermic.

Answer 2

Answer: The correct answer is
`CH_4+2O_2\rightarrow CO_2+2H_2O+212,800Cal`

Step-by-step explanation:

Exothermic reactions are defined as the reactions in which heat energy is released during a chemical reaction. In these reactions, energy of the products is less than the energy of the reactants.
`\Delta H_(rxn)` for these reactions are ought to be negative.

In these chemical reactions, energy term is written on the product side.

From the given chemical reactions, only one reaction satisfies the above information. The chemical reaction is:

`CH_4+2O_2\rightarrow CO_2+2H_2O+212,800Cal`