Practice AND Review Answers

  1. Identify as an acid or base or other and name:
  2. Ca(OH)2 base/calcium hydroxideh. H2CO3carbonic acid
  3. H2SO4sulfuric acidi. HNO3nitric acid
  4. HNO2nitrous acidj. H3PO4phosphoric acid

d. Mg(OH)2base/magnesium hydroxide k. NaOH base/sodium hydroxide

e. CH4neither/methanel. H2SO3 sulfurous acid

f. HIhydroiodic acidm. NH3base/ ammonia

g. CsOH base/ cesium hydroxiden. NaBr neithersalt/ sodium bromide

  1. In an acid is the hydrogen ion concentration higher than or lower than the hydroxide ion concentration? Acid high H+ concentration, low OH- conc
  1. Give me the hydrogen ion concentration range and pH range for acids and give me the hydroxide ion range and pOH range for bases. pH = 0-7 Acid pH Base = 7-14 [H+] = 1X 10-7 to 1X 100 [OH-] = 1X 10-14 to 1X 10-7
  1. What is the pH of a solution that has a hydrogen ion concentration of 2.5x10-5M. What is the pOH of this solution? I think I messed up and had a positive exponentpH = 4.6 pOH = 9.4
  1. If the pOH of a solution is 13.0, what is the HYDROGEN ion concentration? pH= 1 H+ conc =.1
  1. The pH and pOH of a solution must add up to equal what? The hydrogen ion and hydroxide ion concentrations of a solution must add up to equal what?
  1. If the hydroxide ion concentration of a solution is 2.65x10-2, what is the hydrogen ion concentration, pH, and pOH. Is this solution acidic of basic?

1.0X10-14 /2.65x10-2 = [H+] = 3.77x10-13pOH=1.6 pH=12.4

  1. Give the definitions of all three methods of defining acids and bases. (Arrhenius, Bronsted Lowry, and Lewis) Look them up
  1. Is NH3 an Arrhenius base? Is it a Bronsted Lowry base? Explain your answers.

Not Arrhenius base, No OH- present so can’t be Arrhenius, H+ion acceptor to become NH4+

  1. Identify the acid, base, conjugate acid, and conjugate base in the following reactions.
  1. HNO3 + H2O  H3O+ + NO3- b. CO32- + H2O  HCO3- + OH-

Acid baseCACB Base Acid CA CB CH3COOH + H2O  H3O+ + CH3COO- d. H3PO4 + H2O  H+ + H2PO4-

Acid base CA CB Acid base CA CB

  1. H2PO4- + H2O  H+ + HPO42-
  1. Name 4 strong acids and 4 strong bases. Acids-hydrochloric, sulfuric,lemon juice,phosphoric,stomach Bases- NaOH(lye), other hydroxides
  1. What is the molarity of phosphoric acid if 50.0 mL of the solution is neutralized by 45.2 mL of 0.25 M NaOH? Predict products and balance.

H3PO4 + 3NaOH  Na3PO4 + 3H2O

.25M = x/.0452liters NaOH

x= .0113 moles NaOH divided by 3 for mole ratio

.0038 mol acid/.050 liters = .076MH3PO4

  1. How many moles of magnesium hydroxide are needed to completely neutralize 0.25 moles of nitric acid? Predict products and balance.

Mg(OH)2 + 2HNO3 Mg(NO3)2 + 2H2O

Mole ratio .25/2 = .125moles

  1. How many mL of 3.0 M KOH are needed to prepare 870 mL if 0.20 M KOH?

M1V1=M2V2

3.0M(V2) = .20M(870mL)

V2=58mL

  1. If you need 50.0 mL of 0.152 M HCl to neutralize 29.2 mL of Ca(OH)2, what is the molarity of the base?

2HCl + Ca(OH)2 2 H2O + CaCl2

0.152M HCl = x moles/.050 liters

x= .0076 molesAcid

.0038 moles of base/ .0292liters = .13 Molar Ca(OH)2

.26

  1. What is the molarity of a solution of base if 25.0 mL is neutralized by 75.0 mL of 0.40 m acid?

M1V1=M2V2

  1. Define titration. Look it up
  1. How many moles of potassium hydroxide are needed to completely neutralize 1.56 moles of phosphoric acid? Predict products and balance.

3KOH + H3PO4 K3PO4 + 3H2O

4.68 moles

  1. How many moles of calcium hydroxide are needed to neutralize 6.30 moles of nitric acid? Predict products and balance.

Ca(OH)2 + 2HNO3 Ca(NO3)2 + 2H2O 2:1 ratio 6.3 /2 = 3.15 moles

  1. How many milliliters of 2.50M HCl must be added to 25.0 mL of 1.00M potassium hydroxide to make a neutral solution? Predict products and balance.

HCl + KOH  KCl + H2O

1M = x/.025liters

x = .025 moles KOH

2.50 M = .025 mole HCl/ x liters

.01 liters = 10 milliliters

  1. If the [H+] of a solution is 2.3X10-3, what is the pOH of this solution?

-log ( 2.3X10-3) = pH= 2.6pOH= 11.4

  1. What is always the product of an acid/base neutralization?

Water and salt