Question

Solve problem:

Arjun purchased 250 g of glucose (C₆H₁₂O₆) for Rs 40. Find the cost of glucose per mole.

Answer 1

Given: Mass of glucose = 250 g, cost for 250 g glucose = Rs 40, molecular formula of glucose = C₆H₁₂O₆

To find: Cost per mole of glucose

Calculation: Molecular formula of glucose is (C₆H₁₂O₆).

Molecular mass of glucose
= (6 × Average atomic mass of C) + (12 × Average atomic mass of H) + (6 × Average atomic mass of O)
= (6 × 12 u) + (12 × 1 u) + (6 × 16 u)
= 180 u
∴ Molar mass of glucose = 180 g mol⁻¹
Number of moles = `"Mass of a substance"/"Molar mass of a substance"`
= `(250 "g")/(180"g  mol"^-1)`

= `250/180` mol
Now,
`250/180` mol of glucose cost = Rs 40
1 mol glucose cost = x
∴ x = `(40xx180)/250`

= Rs 28.8/mol of glucose

The cost of glucose per mole is Rs 28.8.