Question

A solution contains 30 g of glucose, 20 g of salt in 500 mL of water. Calculate the mass per cent of (a) glucose, (b) salt (density of water = 1 g /mL).

Answer 1

A solution contains 30g of glucose, 20g of salt in 500 ml of water.

we have to find the mass percent of (a) glucose (b) salt.

solution : mass of 500 ml of water = density of water × 500 ml = 1g/ml × 500 ml = 500g

mass of glucose = 30 g

mass of salt = 20g

mass of solution = mass of glucose + mass of salt + mass of water = 30g + 20g + 500g

= 550g

(a) mass percent of glucose = mass of glucose/mass of solution × 100

= 30g/550g × 100

= 5.45 %

therefore the mass percent of glucose is 5.45 %

(b) mass percent of salt = mass of salt/mass of solution × 100

= 20g/550g × 100

= 3.63 %

Therefore mass percent of glucose is 3.63 %