Question

Question

The compound ammonium sulfate consists of two ions, NH4+ and SO42–, both of which are (Blank #1) ions. A molecule of the compound consists of (Blank #2) NH4+ ion(s) and (Blank #3) SO42– ion(s).

Blank #1 Choices
Monatomic
Polyatomic
negative
positive

Blank #2 Choices
1
2
4

Blank #3 Choices
1
2
4

Answer 1

The compound ammonium sulfate consists of two ions, NH4+ and SO42–, both of which are polyatomic ions. A molecule of the compound consists of two NH4+ ion(s) and one SO42– ion(s).

Answer 2

Blank #1: Polyatomic

Blank #2: 2 (see explanation)

Blank #3: 1 (see explanation)

Step-by-step explanation

Both the ammonium ion
`\text{NH}_4^(+)` and the sulfate ion
`\text{SO}_4^(2-)` contain more than one atom in each ion. The two species are thus polyatomic. The chloride ion
`\text{Cl}^(-)`, for example, is monoatomic.

Superscripts above formulae of the ions indicate their charge. Each ammonium ion carries a positive one (+1) charge. Each sulfate ion carries a charge of negative two (-2).

Ammonium sulfate is an ionic compound. A sample of this compound contain myriads of ammonium ions and sulfate ions. The ions are packed in three-dimensional lattices. Thus unlike water, ammonium sulfate does not exist as molecules in nature.

Assuming that the second and third blanks refers to a formula unit, rather than a molecule, of ammonium sulfate. The empirical formula of ammonium sulfate gives the minimum whole-number ratio between the two ions in a sample.

Charges shall balance between the two ions. Ammonium ions are of charge +1. Sulfate ions are of charge -2. The sample shall thus contain two ammonium ions for every one sulfate ion.

The empirical formula of ammonium sulfate is therefore
`(\text{NH}_4)_2\text{SO}_4`.

There are thus two ammonium ions
`\text{NH}_4^(+)` and one sulfate ion
`\text{SO}_4^(2-)` in each formula unit of ammonium sulfate.