Question

Question #2486b

Answer 1

You can determine solubility by using solubility rules like those below.

You indicate the solubility of a compound by writing either the symbol (aq) or (s) after it. If it is soluble in water, the symbol (aq) is used, indicating that the substance dissolves in water, forming an aqueous solution. If a compound doesn't dissolve in water it is insoluble and will be a solid in water, and you use the symbol (s) to indicate this.

Now let's go back to your question about the solubility of ammonium sulfide `("NH"_4)_2"S"`.

Check the solubility rules concerning compounds containing sulfide ions, `"S"^(2-)`. The rules indicate that when ammonium ions, `"NH"_4^+`, combine with sufide ions, `"S"^(2-)"`, the resulting compound, ammonium sulfide is soluble in water. So you would indicate the solubility of the ammonium sulfide as `"(NH"_4)_2"S(aq)"`

Now lets look at another compound, such as barium sulfate, `"BaSO"_4"`. Consult the solubility rules concerning compounds containing the sulfate ion, `"SO"_4^(2-)"`. The rules indicate that when barium ions, `"Ba"^(2+)"`, combine with sulfate ions, the resulting compound is insoluble. You would indicate that barium sulfate is insoluble as `"BaSO"_4"(s)"`.

Here is another solubility table.