Final answer:
To create a 120L solution with 52% base, the professor needs to mix 96L of the 60% solution and 24L of the 20% solution by solving a system of equations involving the total volume and the concentration of the base.
Step-by-step explanation:
How to Mix Solutions with Different Concentrations
To make 120L of a solution that is 52% base from solutions that are 60% and 20% base respectively, we can use a system of equations. Let x represent the amount of the 60% solution and y represent the amount of the 20% solution. The two equations to solve are:
- x + y = 120 (the total volume of the solution needed)
- 0.60x + 0.20y = 0.52 × 120 (the total percentage of the base in the final solution)
To solve this system, we can multiply the second equation by 100 to get rid of the decimals:
Reducing the second equation by dividing by 20 gives:
Subtracting the first equation from this equation gives:
So, x = 96L (the amount of the 60% solution)
We can then substitute x back into the first equation to find y:
- y = 120 - 96
- y = 24L (the amount of the 20% solution)
Therefore, to make a 120L solution of 52% base, the chemistry professor should mix 96L of the 60% solution with 24L of the 20% solution.