At 300 K , for the reaction $\mathrm{A} \rightarrow \mathrm{P}$. the $\Delta \mathrm{S}_{\text {sys }}$ is…

At 300 K , for the reaction $\mathrm{A} \rightarrow \mathrm{P}$. the $\Delta \mathrm{S}_{\text {sys }}$ is $5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$. What is the heat absorbed (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) by the system?
  1. $1.5$
  2. $15$
  3. $1500$
  4. $0.6$

Solution

$\Delta \mathrm{S}_{\text {sys }}=\frac{\mathrm{q}_{\text {sys }}}{\mathrm{T}}$ $q_{\text {sys }}=\Delta S_{S y s} \times T$ $=5 \mathrm{JK}^{-1} \mathrm{~mol}^{-1} \times 300 \mathrm{~K}$ $\begin{aligned} & =1500 \mathrm{~J} \mathrm{~mol}^{-1} \\ & =\frac{1500}{1000} \mathrm{~kJ} \mathrm{~mol}^{-1}\end{aligned}$ $\begin{aligned} & {[1 \mathrm{KJ}=1000 \mathrm{~J}]} \\ & \mathrm{q}_{\text {sys }}=1.5 \mathrm{~kJ} \mathrm{~mol}^{-1}\end{aligned}$

Asked in: AP EAMCET 2024 (18 May Shift 1)

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