Question

A sample of pure magnesium carbonate contains 28.5% magnesium, 14.3% carbon and 57.2% oxygen by mass. Find the mass of magnesium, carbon and oxygen in 15.0 g of magnesium carbonate. Pls answser Fastt

Answer 1

Explanation:

According to the law of constant proportion or law of definite proportion, the elements are always present in definite proportions by mass.

It means 2 gram sample will also contain 40% of calcium, 12% of carbon and 48% of oxygen

Mass of Ca in sample = 2g x 40/100 = 0.8g

Mass of carbon in sample = 2g x 12/100 = 0.24 g

Mass of oxygen in sample = 2g x 48/100= 0.96 g

Answer 2

Explanation:

Pure magnesium carbonate contains 28.5% magnesium,14.3%

carbon and 57.2% oxygen by mass.

By law of conservation of definite proportion, the percentage, by mass, of magnesium, carbon and oxygen in magnesium carbonate will always remain the same everywhere irrespective of how it is formed.

Mass of magnesium present in 15 g of magnesium carbonate

= (28.5% of 15) g = 4.275 g

Mass of carbon in 15g of magnesium carbonate = (14.3% of 15)g = 2.145 g

Mass of oxygen present in 15 g of magnesium carbonate

= (57.2% of 15) g = 8.58 g