Question

11. Chalk contains 40% calcium, 12% carbon and rest oxygen. What is the amount of oxygen in 8 kg of
chalk?​

Answer 1

The Oxygen percentage 38%

Answer 2

Answer :-

Given :-

Chalk contains -

• 40% calcium
• 12% carbon and rest oxygen

To Find :-

• Amount of oxygen in 8 kg of chalk

Solution :-

Chalk has 40% calcium and 12% carbon and the left percentage is of oxygen.

So, to find amount of oxygen in 8 kg of chalk, we first need to find percentage of oxygen in the chalk :-

Percentage of calcium + carbon + oxygen = 100%

40 + 12 + oxygen = 100

% of oxygen + 52 = 100

% of oxygen = 48

Percentage of oxygen in chalk = 48%

Amount of oxygen in 8 kg of chalk = 8 × 48%

= 8 × 48 / 100 kg

= 384 / 100 kg

= 3.84 kg

Amount of oxygen in 8 kg of chalk = 3.84 kg = 3840 g