Concentration = # of moles volume (L) V = 1000 mL V = 1000 mL n = 8 moles [ ] = 32 molar V = 1000 mL V = 1000 mL V = 5000 mL n = 2 moles n = 4 moles n = 20 moles Concentration = 2 molar [ ] = 4 molar [ ] = 4 molar

Making a Dilute Solution remove sample moles of solute initial solution same number of moles of solute in a larger volume mix Making a Dilute Solution diluted solution Timberlake, Chemistry 7th Edition, page 344

Dilution Preparation of a desired solution by adding water to a concentrate. Moles of solute remain the same.

Dilution GIVEN: M1 = 15.8M V1 = ? M2 = 6.0M V2 = 250 mL WORK: What volume of 15.8M HNO3 is required to make 250 mL of a 6.0M stock solution? GIVEN: M1 = 15.8M V1 = ? M2 = 6.0M V2 = 250 mL WORK: M1 V1 = M2 V2 (15.8M) V1 = (6.0M)(.250L) V1 = .095 L of 15.8M HNO3

It’s Your Turn To Try It Out! Pretend you are doing a lab experiment that requires 3 L of a 0.5 M solution of HCl. Your stock solution is 10 M. How much stock solution do you need to add to water to make the needed solution?  M1 = 10 M V1 = ? It is the unknown. M2 = 0.5 M V2 = 3 L  Set up your equation. M1V1 = M2V2

How Did We Solve? Rearrange the equation to solve for V1. V1 = M2V2 / M1 Fill in your known values and solve. V1 = (0.5 M)(3 L) / 10 M V1 = 0.15 L  So you need to add 0.15 L of stock solution to water to make 3 L of diluted solution.

Safety: “Do as you oughtta, add the acid to the watta!”