Question

what is the percentage by mass of glucose in a solution which contain 18g of glucose in 250 g in water​

Answer 1

0.4

Explanation:

Molality (not to be confused with molarity) of a solution is defined as no. of moles of solute dissolved in 1 kg of solvent. In this solution, we have solute as glucose and solvent as water.

Molar mass of glucose (C6H12O6)

=(6×12)+(12×1)+(6×16)=180g

No of moles of glucose in 180 g glucose = 1

No of moles of glucose in 18 g glucose = 0.1

This 0.1 moles of glucose is dissolved in 250 g of water

In 1 kg (or 1000 g) of water, no. of moles of glucose dissovled =4×0.1=0.4