What mass of water must be added to 30.5 g of KNO₃ to prepare a 45.0% by mass solution?

Question

Quizplus · Accepted Answer

Let x be the mass of water added to 30.5 g of KNO₃. Mass of KNO₃ in the solution = 30.5 g Mass of water in the solution = x g Total mass of the solution = 30.5 g + x g According to the question, the solution is 45% by mass: % mass of KNO₃ = (mass of KNO₃ ÷ total mass of solution) × 100% 45% = (30.5 ÷ (30.5 + x)) × 100% Solving for x: 45(30.5 + x) = 3050 1369.5 + 45x = 3050 45x = 1680.5 x = 37.3 g Therefore, 37.3 g of water must be added to 30.5 g of KNO₃ to prepare a 45% by mass solution. The answer is C.

What Mass of Water Must Be Added to 30