Question

The molecular formula of ammonium sulfate is (NH₄)₂ SO₄ . 

a. Find the gram molecular mass (GMM) of ammonium sulfate. 

b. Calculate the number of molecules and atoms in 1.32g of ammonium sulfate.

Answer 1

a. GMM of (NH₄)₂ SO₄ 

= (14+4) × 2 + 32 + 4 × 16 = 36 + 32 + 64 

= 132 g

b. Mole = \(\frac{Mass}{GMM}\) = \(\frac{1.32}{132}\) = \(\frac{1}{100}\) = 0.01

number of molecules

= mol x 6.022 x 10²³ = 0.01 x 6.022 x 10²³

number of atoms

= 0.01 x 6.022 x 10²³ x 15 = 0.15 x 6.022 x 10²³(because, the number of atoms in 1 molecules of (NH₄)₂SO₄ is 15)