syllabus problem section 5I #15

[karen 2c]

When making the ICE table for the chemical equation, why would the equilibrium for NH3 be 0.2+x rather than 0.2 -x?? I know it has something to do with Le Chatlier's principle but I don't think I'm fully understanding how to approach the problem.

[Bailey Shioya 2D]

In this problem, the compound NH3 is placed on the right side of the equation, and is treated as a product. Thus, even though we are given the initial concentration of NH3, we still must add x to 0.2 because we are gaining a mol of NH3.

[Pam Nelson 1B]

NH3 and H2S would both be + x because they are products. NH4HS is a reactant and therefore - x. You assume that the reaction begins with 0 product unless stated otherwise, and in this case, it was stated that NH3 had an initial concentration.