Question

Please show work. I am confused about how to get there.

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	ΔHf° (kJ/mol)	S° (kJ/mol K)
Cr2O3(g)	–1147	0.08120
H2O(l)	–242	0.1187
N2(g)	0	0.1915
(NH4)2Cr2O7(s)	–22.5	0.1137

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Determine Δ S _univ° (in kJ/mol K).

	a.	84.3
	b.	6.03
	c.	5.22
	d.	7.66
	e.	6.39

Answer 1