The Department of Chemistry at the University of Illinois
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Ammonium Dichromate Volcano
What reaction occurs when (NH4)2Cr2O7 is decomposed?
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Ammonium dichromate, (NH4)2Cr2O7, is an orange crystalline solid at room temperature. It can be ignited with high heat, such as that from a bunsen burner.
The orange (NH4)2Cr2O7 is decomposed according to the equation below:
(NH4)2Cr2O7(s) ----> Cr2O3(s) + N2(g) + 4H2O(g)
dark green solid "volcano" is Cr2O3.