#(NH_4)_2Cr_2O_7 (s) -> N2 (g) + 4H_2O (g) + Cr_2O_3 (s) + 200 kJ#. What is the molar ratio?

1 Answer
anor277
Jul 6, 2016

The molar ratio is as you have written.

Explanation:

#(NH_4)_2Cr_2O_7(g) rarr N_2(g) + 4H_2O(l) + Cr_2O_3(s) + Delta#

This is a stoichiometrically balanced equation. It tells us explicitly that #252.1*g# of ammonium chromate decomposes under heating to give #14*g# of dinitrogen gas, #72*g# of water, and #152*g# chromium(III) oxide. If you add up the product and reactant masses, you will see that they agree; and they must agree, that is mass is conserved in every chemical reaction.

So in molar terms, #1# #mol# #"ammonium dichromate"# decomposes to give #1# #mol# #"dinitrogen gas"# + etc. If you are not satisfied, voice your objections, and someone here will have another go.

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