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MHT CET · Chemistry · Thermodynamics (C)

The heat of combustion of carbon is \(-393.5 \mathrm{~kJ} / \mathrm{mol}\). The heat released upon the formation of \(35.2 \mathrm{~g}\) of \(\mathrm{CO}_{2}\) from carbon and oxygen gas is

  1. A \(+315 \mathrm{~kJ}\)
  2. B \(-31.5 \mathrm{~kJ}\)
  3. C \(-315 \mathrm{~kJ}\)
  4. D \(+31.5 \mathrm{~kJ}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(-315 \mathrm{~kJ}\)

Step-by-step Solution

Detailed explanation

\(\mathrm{C}+\mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2}\)
\(\Delta H=-393.5 \mathrm{~kJ} / \mathrm{mol}\)
Heat released upon the formation of \(44 \mathrm{~g}\) of
\(
\mathrm{CO}_{2}=-393.5 \mathrm{~kJ}
\)
\(\therefore\) Heat released upon the formation of \(1 \mathrm{~g}\) of
\(
\mathrm{CO}_{2}=\frac{-393.5}{44} \mathrm{~kJ}
\)
\(\therefore\) Heat released upon the formation of \(35.2 \mathrm{~g}\) of
\(
\begin{aligned}
\mathrm{CO}_{2} &=\frac{-393.5}{44} \times 35.2 \\
& \simeq-315 \mathrm{~kJ}
\end{aligned}
\)