The decomposition of of (g) to (g) + (g) absorbs approximately of energy

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

The decomposition of

1.0\,\text{mol}

\mathrm{N_2O}

(g) to

\mathrm{N_2}

(g) +

\frac{1}{2}\,\mathrm{O_2}

(g) absorbs approximately

82\,\text{kJ}

of energy. To make the overall process as close to thermoneutral as possible, an engineer plans to burn a small amount of a supplemental fuel in the same reactor. Standard molar enthalpies of combustion (

\text{kJ}\,\text{mol}^{-1}

) are:

\mathrm{H_2}

(

-286

\mathrm{CO}

(

-283

\mathrm{CH_4}

(

-890

), and

\mathrm{C}

(graphite) (

-394

). Which option comes closest to canceling the

82\,\text{kJ}

energy requirement? (a) Burn

0.25\,\text{mol}

\mathrm{CO}

concurrently with each mole of

\mathrm{N_2O}

. (b) Burn

0.30\,\text{mol}

\mathrm{CO}

concurrently with each mole of

\mathrm{N_2O}

. (c) Burn

0.10\,\text{mol}

\mathrm{CH_4}

concurrently with each mole of

\mathrm{N_2O}

. (d) Burn

0.30\,\text{mol}

\mathrm{H_2}

concurrently with each mole of

\mathrm{N_2O}

Related theory

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