Hour: ____ Date: ___________
Directions: Acids and bases are usually purchased in concentrated form. Rarely, however, do we want to use the acid or base in its concentrated form – we must dilute it to the exact concentration we want. Use the table below to help you answer the following questions. As always, show your work to earn full credit.
Concentrated Solution | Molarity of Concentrate (M) |
Acetic Acid, Glacial (CH3COOH) | 17.5 |
Ammonium Hydroxide (NH4OH) | 14.5 |
Formic Acid (HCOOH) | 23.6 |
Hydrochloric Acid (HCl) | 12.1 |
Hydrofluoric Acid (HF) | 28.9 |
Nitric Acid (HNO3) | 15.9 |
Perchloric Acid, 60% (HClO4) | 9.1 |
Perchloric Acid, 70% (HClO4) | 11.7 |
Phosphoric Acid (H3PO4) | 14.8 |
Potassium Hydroxide (KOH) | 11.7 |
Sodium Hydroxide (NaOH) | 19.4 |
Sulfuric Acid (H2SO4) | 18.0 |
1. What volume of concentrated hydrochloric acid is needed to make 3.0 L of 1.0 M HCl? .25L
2. What volume of concentrated ammonium hydroxide is needed to make 250 mL of 0.5 M NH4OH? 9ml
3. To perform an experiment, you need 0.300 L of 6.0 M nitric acid. You go to the acid cabinet and discover that you have 100 mL of concentrate. Will you have enough acid to complete the experiment? Show your calculation and explain your answer. w/o sig figs no .265L, w/ sig figs yes .3L
4. You mix 128 mL of an unknown, concentrated acid with water and get 1.54 L of a 1.5 M acid solution. What type of acid is it? 18M Sulfuric Acid
5. You need to make 300 L of 2.25 M perchloric acid. It costs $25.95 for a 4.00 liter bottle of 60% HClO4, and $34.95 for a 4.00 liter bottle of 70% HClO4. Should you buy the 60% or the 70% bottles? Show your calculations and explain your answer. 60% is $493.05 for 19 bottles, 70% is $524.25 for 15 bottles. Buy 60%
6. If I have 340 mL of a 0.5 M NaBr solution, what will the concentration be if I add 560 mL more water to it? .2M
7. If I dilute 250 mL of 0.10 M lithium acetate solution to a volume of 750 mL, what will the concentration of this solution be? .033M
8. If I leave 750 mL of 0.50 M sodium chloride solution uncovered on a windowsill and 150 mL of the solvent evaporates, what will the new concentration of the sodium chloride solution be? .63M
9. To what volume would I need to add water to the evaporated solution in problem 8 to get a solution with a concentration of 0.25 M? 1500mL