Pls tell how to do Qn 1

Dear Student,
1 mole of PbS = 207 + 32 = 239 g
1 mole of PbO = 207 + 16 = 223 g

(i) 239 g of PbS is equivalent to 1 mole of PbS. So, 478 g of PbS is equivalent to 2 moles of PbS.
2 moles of PbS produces 2 moles of PbO. Thus,
478 g of PbS produces

2 \times 223 g = 446 g

of PbO.
(ii) 1 mole of any gas at S.T.P. occupies 22.4 litres.
2 moles of PbS produces 2 moles of SO₂.
Thus,

2 \times 22.4 l i t r e s

of SO_{2 is produced by 478 g of PbS at STP.
5.6 litres}of SO_{2 is produced by $\frac{478}{2 \times 22.4} \times 5.6 = 59.75 g$ of of PbS at STP.
(iii) 2 moles of}

S O_{2}

_{requires 3 moles of $O_{2}$ .}
22.4 litres of

S O_{2}

= _{1 mole of}

S O_{2}

5.6 litres of

S O_{2}

\frac{5.6}{22.4} = \frac{1}{4} m o l e s

So,

\frac{1}{4} m o l e s o f S O_{2} = \frac{3}{2} \times \frac{1}{4} = \frac{3}{8} m o l e s o f O_{2} .

Regards

View Full Answer