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. Substance AH? (kJ/mol) Sº (kJ/mol K) Cr2O3(g) -1147 0.08118 H2O(1) -242 0.1187 N2(g) 0.1915 (NH4)2Cr2O7(s) -22.5 0.1137 Determine ASuniy (in kJ/mol K). A) 7.66 B) 6.39 C) 84.3 D) 5.22 E) 6.03

Explain the answer in details, please

Answer 1

.. © (NH4)2 Cr2O7 (5) = N269) +4420 (9) + Cr203.69) . A Höxn = 4H [N2 (9)] + 4.4Hp [H2009)] +AH [CraD36] – <Hj [CNH4)265207 (5)] = [o - 4x 242 – 1147 -(- 2015) :3 - 2092.5 KJ As sy = 5°[N2C%]]+4.4.5.° H2009)] + 5°C crz O3(g)] - s®[ CNHa)267307(S)] =(0.1915 +4x D: 1187 + 0.08118 - 0:1137) KJ/K = 0.63378 KJ/K .: 45 surrounding -- 4H x = + 2092.5 KJ/K = + 7:021813 - [Heat released in reaction will be absorbed by surrounding ] :: KJ/K : .. os ünèv = 45 Sys + 45 surrounding = (0.63378 +7.02181) Wyk = 7.65559 KJK = 7.66 kJ/K - Ans ②