Find value of Q from following equations. (i) $\mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})}…

Find value of Q from following equations. (i) $\mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \Delta \mathrm{H}=\mathrm{QkJ}$ (ii) $\mathrm{C}_{(\mathrm{s})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \Delta \mathrm{H}=-\mathrm{xkJ}$ (iii) $\mathrm{C}_{(\mathrm{s})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \cdot \Delta \mathrm{H}=-\mathrm{ykJ}$
  1. $-(x+y) k J$
  2. $\quad(x-y) k J$
  3. $\frac{-\mathrm{x}+\mathrm{y}}{2} \mathrm{~kJ}$
  4. $\frac{\mathrm{x}+\mathrm{y}}{2} \mathrm{~kJ}$

Solution

(ii) $\mathrm{C}_{(\mathrm{s})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{(\mathrm{g})} \quad \Delta \mathrm{H}=-\mathrm{x}$ (iii) $\mathrm{CO}_{(\mathrm{g})}+\frac{1}{2} \mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \quad \Delta \mathrm{H}=-\mathrm{y}$
Adding equations (ii) and (iii), we get the required equation; (i) $\mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})} \longrightarrow \mathrm{CO}_{2(\mathrm{~g})} \quad \Delta \mathrm{H}=\mathrm{Q}=-(\mathrm{x}+\mathrm{y}) \mathrm{kJ}$ [Note: The equation (ii) and (iii) from the question is modified to apply appropriate textual concepts.]

Asked in: MHT CET 2024 (03 May Shift 2)

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