5. How many atoms and molecules of sulphur are present in 64.0 g of sulphur (S 8 )?

There are atoms and molecules in the compound.

Explanation:

The molar mass of the sulphur is . The Avogradro's Law states that exists . The quantity of atoms in a quantity of mass is derived from dividing the mass by the molar mass and multiplying it by the Avogadro's Number. That is:

Where:

- Mass of the sample, measured in grams.

- Avogadro's Number, measured in atoms per mole.

- Molar mass of the sulphur, measured in grams per mole.

If , and , then:

There are atoms in the compound.

Now, the molecular weight of the compound is:

The quantity of molecules in a quantity of mass is derived from dividing the mass by the molecular weight and multiplying it by the Avogadro's Number. That is:

Where:

- Mass of the sample, measured in grams.

- Avogadro's Number, measured in atoms per mole.

- Molecular weight of the compound (octosulphur), measured in grams per mole.

If , and , then:

There are molecules in the compound.