Name Hour Acids, Bases, Salts and Neutralization Practice Test A
Objective 1: Solve problems involving the molarity of a solution 1. What is the molarity of a solution made by dissolving 2.5 moles of sodium phosphate in 100 ml? 2. How many grams of calcium nitrate are needed to make 750 ml of a 3 M solution? 3. What is the molarity of a solution made by dissolving 0.15 moles of aluminum chloride in 15600 ml? Score: Objective 2: Describe how to prepare dilute solutions from more-concentrated solution of known molarity. 1. How many milliliters of a 5.0 M stock solution of ammonium sulfide do you need to dilute it to 700 ml of 0.1 M? 2. What is the concentration of a solution made by diluting 10 ml of a 12 M HCl solution to a total volume of 2000 ml? 3. Completely describe how you would prepare 250 ml of a 0.05 M solution of sodium fluoride from a 5 M stock solution. Score:
Objective 3: Name an acid or base when given the formula, or give a formula from the name of an acid or base. 1. Write the formula of the following acids and bases: a. Hydrosulfuric acid b. Sulfurous acid c. Sulfuric acid 2. Write the name for the following acids and bases: a. H 3 PO 3 b. H 3 P c. Al(OH) 3 Score: Objective 4: Given the hydrogen-ion or hydroxide-ion concentration, calculate a ph. Indicate if a solution is acid, basic, or neutral. Calculate the ph of the following solutions. Indicate if it is acidic, basic or neutral. a. [H + ] = 2.3 x 10 5 b. [OH - ] = 3.2 x 10-11 c. [OH - ] = 9.1 x 10-2 d. [H + ] = 3.8 x 10 7 e. [OH - ] = 1 x 10-7 Score: Objective 5: Given the ph or poh of a solution, calculate the hydrogen-ion or hydroxide ion concentration. 1. Calculate the [H + ] from the following values: a. ph = 3.8 b. poh = 9.2 c. poh = 1.9 d. ph = 10.6 2. Calculate the [OH - ] from the following values: a. ph = 5.8 b. poh = 13.4 c. poh = 2.7 d. ph = 4.6 Score:
Objective 6: Calculate a ph of a solution by working molarity problems. 1. Calculate the ph of a solution made by dissolving 0.1 grams of nitric acid in a total volume of 1500 ml: 2. Calculate the ph of a solution made by dissolving 5 grams of sodium hydroxide in a total volume of 2500 ml. 3. Calculate the ph of a solution made by dissolving 10 grams of hydrobromic acid in a total volume of 750 ml. Score: Objective 7: Identify the conjugate base associated with a given Bronsted-Lowry acid and the conjugate acid with a given Bronsted-Lowry base. 1. Give the conjugate acid of each of the following bases: a. Oxide ion b. Hydrogen sulfate ion c. Water d. Fluoride ion 2. Give the conjugate base of each of the following acids: a. Hydrosulfuric acid b. Water c. Hydrocyanic acid d. Hydrogen carbonate ion 3. Label the following species in the following equilibrias as either acid, base, conjugate acid or conjugate base. a. HCO 3-1 (aq) + H 2 O (l) = H 2 CO 3 (aq) + OH -1 (aq) b. HCN(aq) + H 2 O (l) = H + (aq) + CN c. NH 3 + H 2 O = NH 4 + + OH - Score:
Objective 8: Perform calculations involving Ka or Kb for weak acids and weak base equilibrium. 1. Calculate the ph of each of the following solutions: a. 0.095 M propionic acid (HC 3 H 5 O 2 ), Ka = 1.3 x 10-5 b. 0.10 M Hydrogen Chromate Ion (HCrO 4-1 ), Ka = 3.0 x 10-7 c. 0.12 M Pyridine (C 5 H 5 N), Kb = 1.7 x 10-9 2. Calculate the Ka or Kb of the following solutions: a. A student prepared a 0.10 M solution of formic acid (HCHO 2 ) and measured its ph using a ph meter. The ph at 25 C was found to be 2.38. Calculate the Ka for formic acid at this temperature. b. Codeine (C 8 H 21 NO 3 ) is a weak organic base. A 5.0 x 10-3 M solution of codeine has a ph of 9.95. Calculate the value of Kb for this substance. Score:
Objective 9: Calculate the concentration of an acid or a base by using solution stoichiometry.(titration problems) 1. Calculate the volume of a 2 M Hydrochloric acid needed to completely neutralize 50 ml of a 3.5 M Magnesium Hydroxide solution. 2. A student performed a titration and found that it took 50 ml of a 0.5 M solution of hydrochloric acid to completely neutralize 30 ml of aluminum hydroxide. Calculate the molarity of the base. 3. How many grams of sulfuric acid are necessary to completely neutralize 10 grams of sodium hydroxide? Score: Objective 10: Distributed Practice: Part 1: Atomic Structure: Fill in the following grid: Element Symbol Atomic Mass Protons Neutrons Electrons Number Number Sodium 23 S 17 Bromine 79 Part 2: Electron Dots: Draw the Lewis Dot Structure for the following molecule: Hydrocyanic acid
Part 3: Calculate a Molecular Formula: Show all work. Epinephrine (adrenaline), a hormone secreted into the blood stream in times of danger or stress, contains 59% C, 7.1%H, 26.2% O, and 7.7%N by mass; its molecular mass is about 180 amu. Part 4: Ideal Gas Law problem: In the Dumas-bulb technique for determining the molar mass of an unknown liquid, you vaporize the sample of a liquid that boils below 100 C in a boilingwater bath and determine the mass of vapor required to fill the bulb. See diagram below; From the following data, calculate the molar mass of the unknown liquid; Mass of unknown vapor = 1.012 g Volume of Bulb = 354 ml Pressure = 742 mm Hg Temperature = 99 C Score: