Question

Trey buys a 500 ml bottle of rubbing alcohol. the bottle contains a solution of 70% alcohol and 30% water. the instructions for his toy train set say he should use a solution of 40% alcohol and 60% water to clean the tracks. write and solve an equation to determine how much water trey must add to the solution he purchased to have the correct solution for cleaning the tracks

Answer 1

To solve this we use the equation,

M1V1 = M2V2

where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume.

.70(V1) = .40(500 + v1)

V1 = 666.67 mL of water should be added