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AP EAMCET · Chemistry · Thermodynamics (C)

When ' \(\mathrm{X}\) ' \(\mathrm{g}\) of graphite is completely burnt in a bomb calorimeter in excess of \(\mathrm{O}_2\) at \(298 \mathrm{~K}\) and \(1 \mathrm{~atm}\) pressure as given in the equation
\(\mathrm{C}\) (graphite) \(+\mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{CO}_2(\mathrm{~g})\)
The temperature of calorimeter raised from \(298 \mathrm{~K}\) to \(302 \mathrm{~K}\). If the heat capacity of the calorimeter and molar enthalpy change for the reaction at \(1 \mathrm{~atm}\) and \(298 \mathrm{~K}\) are \(20.7 \mathrm{~kJ} \mathrm{~K}^{-1}\) and \(-248.4 \mathrm{~kJ} \mathrm{~mol}^{-1}\), ' \(\mathrm{X}^{\prime}\) in \(\mathrm{g}\) is

  1. A 8
  2. B 2
  3. C 3
  4. D 4
Verified Solution

Answer & Solution

Correct Answer

(D) 4

Step-by-step Solution

Detailed explanation

Heat released in the reaction with ' \(\mathrm{X}\) ' g carbon \(\mathrm{Q}=\mathrm{C}_{\mathrm{P}} \Delta \mathrm{T}=(20.7)(4)=82.8 \mathrm{~kJ}\) 1 mole or \(12 \mathrm{~g}\) of carbon (graphite) gives \(248.4 \mathrm{~kJ}\) heat ' \(\mathrm{X}\) ' g carbon gives…