What weight of potassium bromide, KBr, could be recovered by evaporating 650.0 g of 15.0 percent KBr solution to dryness?

Answer 1

15% KBr (w/w) means 15 g KBr/100 g soln. So how many grams KBr will you find in 650 g? That will be 15 x 650/100 = ? That's how much you can obtain by evaporation assuming good lab technique.