When ignited,solid ammonium dichromate decomposes in a fiery display.This is the reaction for a "volcano" demonstration.The decomposition produces nitrogen gas,water vapor,and chromium(III)oxide.The temperature is constant at 25°C.

-Determine $\Delta$S° reaction (in kJ/mol K).

Question

When ignited,solid ammonium dichromate decomposes in a fiery display.This is the reaction for a "volcano" demonstration.The decomposition produces nitrogen gas,water vapor,and chromium(III)oxide.The temperature is constant at 25°C.

-Determine $\Delta$S° reaction (in kJ/mol K).

Quizplus · Accepted Answer

To find the standard entropy change ($\Delta S^\circ$) for the reaction, we use the formula:$$\Delta S^\circ = \sum S^\circ_{\text{products}} - \sum S^\circ_{\text{reactants}}$$Given entropies ($S^\circ$) in kJ/mol K:- Cr$_2$O$_3$(g): 0.08118- H$_2$O(l): 0.1187- N$_2$(g): 0.1915- (NH$_4$)$_2$Cr$_2$O$_7$(s): 0.1137The balanced chemical equation for the decomposition is:$$(NH_4)_2Cr_2O_7(s) \rightarrow Cr_2O_3(g) + N_2(g) + 4H_2O(g)$$Calculating $\Delta S^\circ$ for the reaction:$$\Delta S^\circ = [1 \times 0.08118 + 1 \times 0.1915 + 4 \times 0.1187] - [1 \times 0.1137]$$$$\Delta S^\circ = 0.08118 + 0.1915 + 0.4748 - 0.1137 = 0.63378$$Thus, the correct answer is 0.6338 kJ/mol K.

When Ignited,solid Ammonium Dichromate Decomposes in a Fiery Display Δ\DeltaΔ S° Reaction (In KJ/mol K)

When Ignited,solid Ammonium Dichromate Decomposes in a Fiery Display $\Delta$ S° Reaction (In KJ/mol K)