Question

a mixture of sodium bicarbonate an ammonium bicarbonate is 75.9% bicarbonate by mass. what is the mass percent of sodium bicarbonate in the mixture?

Answer 1

The question is quite ambiguous because one of the data is not clearly stated. It says that the mixture consists of two compounds:

- sodium bicarbonate
- ammonium bicarbonate

Thereafter, it says that it is 75.9 % bicarbonate, but it does not specify which bicarbonate. Thus, it might be the sodium bicarbonate or the ammonium bicarbonate. It is apparent that the information is omitted by mistake.

As we are asked to find the mass percent of sodium bicarbonate is in the mixture, we can suppose that the 75.9% content is of ammonium bicarbonate.

With that said, we calculate the mass percent of sodium bicarbonate, because there are only two compounds and so you know that both add up the 100% of the mixture.

In formulas:

100% = %m/m sodium bicarbonate + %m/m ammonium bicarbonate = 100%

=> % m/m sodium bicarbonate = 100% - % m/m ammonium bicarbonate

=> % sodium bicarbonate = 100% - 75.9% = 24.1%

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