Question

The molar mass of sulphate ion is 96 g mol ^-1. What is the meaning of this statement?

Answer 1

• Molar Mass - The molar mass of the compound is the mass of 1 mole of that substance. The unit of molar mass is grams/mole.
• 1 mole of compound = 6.022 x 10 ²³ is called Avogadro's number.
• The molar mass of sulphate ion (SO₄ )^-2 is 96 g mol ^-1.
• The number of Sulphur atoms in sulphate ion (SO₄ )^-2 = 1 and mass number = 32.
• Number of Oxygen atoms in sulphate ion (SO₄ )^-2 = 4 and mass number of 4 oxygen atoms = 4 x 16 = 64.
• Hence molar mass = 32 + 64 = 96 g / mole ^-1.

Therefore Molar mass of sulphate ion is 96 g mol ^-1.