Concentration and Dilutions

Do not write on this paper. Show all work. No work = no credit. Place a rectangle around your final answers. All numerical answers must have the appropriate unit. No unit or wrong unit = - ½ credit.

1. What is the weight percentage of a sugar solution if 30 grams of sugar are dissolved in 70 grams of water?

2. Hydrogen peroxide is sold commercially as a 3% solution. How many grams of hydrogen

peroxide are dissolved in a one-pint bottle (1 pint of 3% H2O2 solution weighs about 473 grams)?

3. How much water is needed to make a 15% (by volume) ethanol solution that contains 45 mL of ethanol?

4. What is the molar concentration of a solution that contains 0.500 mol HNO 3 dissolved in enough water to make 0.100 L of solution?

5. What is the molar concentration of a solution that contains 20.0 grams of H2SO4 dissolved in enough water to make 300. mL of solution?

6. How many grams of sodium chloride are dissolved in 35.0 mL of a 0.250 M solution?

7. If you have 16.0 grams of KNO3 and wish to use it all to produce a 1.10 M solution, what volume will the solution have?

8. If 2.00 mL of a 10.0 M HCl solution is diluted to 200. mL using distilled water, what is the new molar concentration?

9. You need to prepare 250. mL of a 0.150 M nitric acid solution. The stock nitric acid solution is 15.0 M. How much stock should you use?

10. To how much water should you add 1.50 mL of a 6.00 M lye solution to dilute it to 1.80 M?

11. If 25.0 mL of 3.00 M HCl solution is mixed with 30.0 mL of 1.80 M HCl solution, what is the concentration of the resulting solution? Assume volumes are additive.