Theory

The reaction that occurs is:

(NH)CrO(s) CrO(s) + N(g) + 4HO(l)



Further details

The value for the standard molar entropy of ammonium dichromate has been estimated by Latimer's rules, which state that the entropy of each atom of each element in a compound in JK mol is given by:

S = (1.5 R ln ) - 3.92

(where is the relative atomic mass of the element and R is the gas constant) and that the entropy of a compound is the sum of the entopies of all elements in the compound.

This rule may be found useful for estimating the entropies of other compounds which are not readily available in the literature.

Safety

Wear eye protection.

Dispose of the residue in a sealed plastic bag placed in the dustbin.