Question

calculate the no. of moles in-
1. 9.0 g of aluminium
2. 392 g of sulphuric acid
3. 44.8 litres of carbon dioxide at S.T.P.

Answer 1

1) Molar mass of aluminium = 27 g
Given mass of aluminium = 9 g
$$\begin{gathered} \text{Number of moles (n)\hspace{0.17em}}=\frac{\text{Given mass}}{\text{Molar mass}} \\ n=\frac{9}{27}=0.33\text{moles} \end{gathered}$$

2) Given mass of H₂SO₄ = 392 g
Molar mass of H₂SO₄ = 98 g
$\text{n}=\frac{392}{98}=4\text{moles}$

3) Number of moles of 22.4 L of CO₂ at STP = 1 Mole
Number of moles of 44.8 L = 44.8 / 22.4 = 2 moles