Question

Cost of sugar ($C_{12}{H}_{22}{O}_{11}$) is Rs. $40$ per kg. Calculate its cost per mole.

Answer 1

Let's first find the molar mass of sugar by adding up the atomic masses of all atoms in it.

Molar mass of sugar ($C_{12}{H}_{22}{O}_{11}$) = (12 $\times$ 12) + (22 $\times$ 1) + (11 $\times$ 16) = 144 + 22 + 176 = 342 g/mol

Now, let's find out how many moles of sugar are in 1 kg, i.e. 1000 g sugar.

Number of moles = $\frac{Mass}{Molarmass}$ = 1000/342 = 2.92 mol

It's given that 1 kg sugar costs Rs. 40

$\therefore$ Cost of 2.92 moles sugar = Rs. 40

Cost of one mole of sugar = 40/2.92 = 13.69 Rs. per mole