How much water must be evaporated from a 300 L tank of 2% salt solution to obtain a 5% solution?
To find out how much water must be evaporated from the tank, we need to determine the amount of salt in the initial solution and the final required volume.
Step 1: Find the amount of salt in the initial solution.
The initial solution is 2% salt solution. This means that there are 2 L of salt for every 100 L of solution. So, in a 300 L tank, there would be (2/100) * 300 = 6 L of salt.
Step 2: Determine the amount of salt required in the final solution.
The final solution is a 5% salt solution. This means there should be 5 L of salt for every 100 L of solution. As we have already determined that the initial solution contains 6 L of salt, we need to subtract this amount to find out how much salt needs to be added. Thus, we need (5-2) = 3 L of salt.
Step 3: Find the volume of the final solution.
To get a 5% solution, we need to calculate the final volume by dividing the desired amount of salt (3 L) by the concentration of salt in the final solution (5 L/100 L). Thus, the final volume is (3/5)*100 = 60 L.
Step 4: Calculate the amount of water that needs to be evaporated.
Since the total volume in the tank should remain 300 L, we need to find out how much water needs to be evaporated to obtain a final volume of 60 L. By subtracting the final volume from the initial volume, we get the amount of water to be evaporated: 300 - 60 = 240 L.
Therefore, 240 liters of water must be evaporated from the 300 L tank of 2% salt solution to obtain a 5% solution.