Question

N. Calculate the number of moles of magnesium oxide, MgO in i. 80 g and ii. 10 g of the compound. (Average atomic masses of Mg = 24 and 0 = 16) (Ans. i. 2 mol ii. 0.25 mol)​

Answer 1

Answer -

n1 = 2 mol

n2 = 0.25 mol

Explaination -

Molar mass of MgO is given by -

M = 24 + 16

M = 40 g/mol

(i) W1 = 80 g

Number of moles of MgO will be -

n1 = W1/M

n1 = 80/40

n1 = 2 mol

(ii) W2 = 10 g

Number of moles of MgO will be -

n2 = W1/M

n2 = 10/40

n2 = 0.25 mol