A chemist wants to make 55 mL of a 17% acid solution by mixing a 13% acid solution and an 18% acid solution. How many milliliters of each solution should the chemist use?

Question

anonymous · Answer

set up the following equation$$0.17={0.13x+0.18(55-x)\over 55}$$I'm assuming your solutions are percent mass by volume (not sure if in the end it matters). If you are using x mL of one solution, you will be using 55-x mL of the second solution (again doesn't matter which, just remember what goes with what so you don't reverse the answer in future problems). Solve for x (mL of 13% acid solution)$$0.17*55={0.13x+9.9-0.18x}$$$$0.05x=0.55$$$$x=11mL$$
So you need 11mL of the 13% acid solution and 44mL of the 18% acid solution. This makes sense since your target concnetration is 17% so you would expect the majority of the mixture to be the 18% solution.