Question

If 500 g of dextrose are dissolved in 600 mL of water with a resultant final volume of 1 L, what is the percentage strength of dextrose in the solution on a w/w basis?

Answer 1

%(w/w) =( mass solute / mass solution) x 100

mass solute = mass of dextrose( solute) = 500 g

mass solution = mass solute(dextrose) + mass solvent(water)

= 500 g + mass solvent(water)

Assuming that density of water is 1g / mL or 1 kg /L,mass can be calculated by following formula.

Mass = Density x volume

= 1 g/mL x 600 = 600 g

Mass of solvent(water) = 600 g

Now mass solution = mass solute + mass solvent

= 500 g + 600 g = 1100 g

Now calculate% w /w using the below formula

% w/w =(mass solute/ mass solution) x 100

(500 /1100) x 100 = 0.4545 x 100 = 45.5 %