Q.7 (i) Chalk contains calcium, carbon and oxygen in the ratio 10 : 3 : 12. Find the Percentage of carbon in chalk.

(ii) If in a stick of chalk, carbon is 3 g, what is the weight of the chalk stick?

(ii) If in a stick of chalk, carbon is 3 g, what is the weight of the chalk stick?

(i) Sum of the ratio parts = 10 + 3 + 12 = 25

\(\therefore \) Percentage of carbon in chalk

=\(\frac{3}{25} \) ×100%=12%

Hence, the Percentage of carbon in chalk = 12%

(ii) Weight of carbon = 3 g

\(\therefore \)Weight of chalk =\(\frac{3}{3} \) × 25 g = 25 g

Hence, the weight of chalk = 25 g