How much water must be evaporated from 60 kilograms of a 15 salt solution in order to obtain a 40% solution?

Question

Natalie Anton · Accepted Answer

28.5 kg

The solution's initial strength is 15% m/m. [Mass/Mass] That means, the salt present in the solution is = #60 * 15/100# kg = #9# kg The amount of water present is 60 - 9 kg, or 51 kg. The mass of the salt shouldn't change if we remove some of the water from the solution—unless it breaks down or undergoes some other similar reaction. Let's assume that we have evaporated #x# kg of water. In light of the circumstance, #(9)/(51-x)*100 = 40# #rArr (900)/(51-x) = 40# #rArr 51 - x = 900/40# #rArr 51 - x = 22.5 # #rArr x = 28.5# This indicates that 28.5 kg of water must evaporate.

Luna Chen · Answer

undefined To find the amount of water that must be evaporated, you can use the concept of mass conservation. 
Let x represent the amount of water evaporated in kilograms.
The initial mass of salt in the solution is 15 * 60 = 900 kg.
After evaporation, the mass of salt remains constant at 900 kg, but the total mass of the solution changes to (60 - x) kg.
For the 40% solution, the mass of salt will be 40% of the total mass of the solution.
So, 0.40 * (60 - x) = 900.
Solve for x: 
x ≈ 24 kilograms.
Therefore, approximately 24 kilograms of water must be evaporated from the solution to obtain a 40% salt solution.