Answer:
Step-by-step explanation:
- The highlighted text is discussing the process of making a solution with a specific concentration of acid.
- The student needs to make 20ml of a solution that is 60% acid, which means that 60% of the solution is composed of acid.
- To make this solution, the student plans to mix two different solutions together: one that is 70% acid and another that is 45% acid.
- The question is asking how much of the 45% acid solution the student will need to mix with the 70% acid solution to create the desired 60% acid solution.
- To solve this problem, the student needs to use a formula that takes into account the concentration of each solution and the desired concentration of the final solution.
- One possible formula is: (amount of 70% solution needed) + (amount of 45% solution needed) = 20ml (total volume of final solution) and (0.7 x amount of 70% solution) + (0.45 x amount of 45% solution) = 0.6 x 20ml (desired concentration of acid in final solution).
- Using algebra, the student can solve for the amount of 45% solution needed: amount of 45% solution = (0.6 x 20ml) - (0.7 x amount of 70% solution) / 0.45.
- The final answer will depend on the amount of 70% solution the student decides to use.