Precipitates

1. Determine the identity of a precipitate from experimental data

Precipitates

Precipitate problems are basically logic games:

Identify the solid formed

In this case, the precipitate is zinc sulfide. From the first 2 equations, we can tell that zinc sulfide, lithium bromide, and potassium bromide are the only possible products. However, the final equation shows us that lithium bromide is not a product. Since the white precipitate must show up in both of the first 2 equations, and the only common product between the 2 reactions in the first equation is zinc sulfide, the precipitate must be zinc sulfide.