Chapter 14 and 15 Review

Chapter 14 and 15 Review Acids and Bases

Classify the following as either properties of acids or properties of bases or BOTH: • Tastes sour • Caustic/corrosive (burning/destroying) • Feels slippery • Typically begin with an H atom • Has a pH greater than 7 • Has a pH less than 7 • Tastes bitter • Turns blue litmus paper red • Turns red litmus paper blue • Typically end in OH • An electrolyte (form ions in solution, so can conduct electricity) • Donate OH-ions when dissolved in water • Will react with many metals • Donate H+ ions (form H3O+ ions in water)

Answers • A • Both • B • A • B • A • B • A • B • B • Both • B • A • A

Write the formula for the following acids. Then label as monoprotic, diprotic, or triprotic. • Acetic acid • Hydrochloric acid • Nitric acid • Phosphoric acid • Sulfuric acid

Answers • CH3COOH - monoprotic • HCl - monoprotic • HNO3 - monoprotic • H3PO4 - triprotic • H2SO4 - diprotic

1. Explain the difference between a weak acid or base and a strong acid or base. 2. A strong acid produces a _____ conjugate base. A weak acid produces a ____ conjugate base. 3. A strong base produces a _____ conjugate acid. A weak base produces a ______ conjugate acid. 4. Which is a better electrolyte – a strong acid or a weak acid? Why?

Answers • A weak acid or base is one that only partially dissociates(ionizes) in solution whereas a strong acid ionizes or dissociatescompletelyin solution. 2. A strong acid produces a _weak_ conjugate base. A weak acid produces a __ strong__ conjugate base. 3. A strong base produces a __ weak _ conjugate acid. A weak base produces a __ strong _ conjugate acid. 4. A strong acid is a better/stronger electrolyte (conducts electricity better) because it dissociates completely and therefore creates more ions to conduct electricity than a weak acid does.

Write the 3 definitions of acids and bases (fill in the table below)

Answer

Identify the B-L acid, B-L base, conjugate acid, and conjugate base: • H2CO3 + H2O  HCO3- + H3O+ • H2O + HCO3- H2CO3 + OH- • H2O + HCl H3O+ + Cl- • NH3 + H2O OH- + NH4+

Answers • A + B  CB + CA • A + B  CA + CB • B + A  CA + CB • B + A  CB + CA

Write the formula for a hydrogen ion. • A hydrogen ion is just a single __________. • What happens to the hydrogen ion in an aqueous solution? (Write the equation). • Write the formula for a hydroxide ion. • Write the formula for a hydronium ion. • How does acid rain form? – Fill in the blanks below. • ______ from the burning of ______ forms sulfur dioxide, SO2. • The SO2 is then converted to ______, sulfur trioxide. • The sulfur trioxide reacts with water to form ______. • ______ + H2O ______ • The ______ precipitates with water to form ______.

Answers • H+ • proton • H+ + H2O  H3O+ • OH- • H3O+ • Sulfur from the burning of oil and coal forms sulfur dioxide, SO2. • The SO2 is then converted to SO3, sulfur trioxide. • The sulfur trioxide reacts with water to form sulfuric acid. • SO3+ H2O H2SO4 • The sulfuric acid precipitates with water to form acid rain.

Identify the reactants in the following equations as either Lewis acids or Lewis bases: (draw Lewis structures!) • Cl- + AlCl3AlCl4- • H2O + HF F- + H3O+ • H+ + NH3 NH4+

Answers • Cl- + AlCl3 AlCl4- • H2O + HF  F- + H3O+ • H++ NH3 NH4+ Red – acid Blue - base

Complete and balance each of the following equations: • HNO3 + KOH • Ca(OH)2+ HNO3 • Mg(OH)2+ HCl 4. What type of reactionsare these? 5. What is the name of the salt formed in #3?

Answers • HNO3 + KOHKNO3 + H2O • Ca(OH)2 + 2HNO3Ca(NO3)2 + 2H2O • Mg(OH)2 + 2HClMgCl2 + 2H2O 4. Neutralization 5. Magnesium chloride

None of these are calculations… • Write the equation for the self-ionization of water. 2H2O • What is the molar concentration of hydronium ions in water at 25C? • What is the molar concentration of hydroxide ions in water at 25C? • What two ion concentrations are equal in a neutral solution? • A solution with a [H3O+] concentration of 1.0 x 10-3 is _________ (acidic, basic, neutral). • A solution with a [H3O+] concentration of 1.0 x 10-13 is _________ (acidic, basic, neutral). • A solution with an [OH-] concentration of 1.0 x 10-10 is __________ (acidic, basic, neutral). • A solution with an [OH-] concentration of 1.0 x 10-2 is __________ (acidic, basic, neutral). • What is the [OH-] in a 0.01 M solution of NaOH? • What is the [OH-] in a 12 M solution of Ca(OH)2? • What is the [H3O+] in a 0.01 M solution of HCl? • What is the [H3O+] in a 3 M solution of H3PO4? • _______ indicates the hydronium ion concentration of a solution.

Answers • 2H2O H3O+ + OH- • 1 x 10-7 M • 1 x 10-7 M • H3O+and OH- • Acidic • Basic • Acidic • Basic • 0.01 M • 24 M • 0.01 M • 9 M • pH

Phenolphthalein and bromothymol blue are _________, which means they turn different colors as the pH changes. • The pH range over which an indicator changes color is called the __________. • __________ are made by mixing several different indicators. Because they turn so many different colors, they can provide a fairly accurate way of distinguishing pH. • Paper soaked in universal indicator is called ___________. • A _______ determines the pH of a solution by measuring the voltage between two electrodes that are placed in the solution. It provides a more precise pH reading than pH paper. • __________ reactions occur between acids and bases

Answers • Indicators • Transition interval • Universal indicators • pH paper • pH meter • neutralization

The purpose of titration is to determine the ________ of an acid or a base. • What is the standard solution? • What data do you collect in lab to determine the unknown concentration? • What formula do you use when doing titration calculations? • The point in a titration when the acid and base are present in equal amounts (# moles of acid = # moles of base) is the ______________. • The point in a titration at which an indicator changes color is called the _________.

Answers • Concentration • The “known” solution (the one you know the concentration of)– in our lab it was the acid b/c we knew the concentration of the HCl. • The volume of standard solution added in order to neutralize the acid or base. • MAVA=MBVB • Equivalence point • End point

Titration calculations: • In a titration, 25.9 mL of 3.4 x 10-3 M NaOH neutralized 16.6 mL of HCl solution. What is the molarity of the HCl solution? • Find the molarity of a KOH solution given that 428 mL of the solution is neturalized in a titration by 115 mL of 6.7 x 10-3 M HNO3. • Suppose that 10.1 mL of HNO3 is neutralized by 71.4 mL of a 4.2 x 10-3 M solution of KOH in a titration. Calculate the concentration of the HNO3 solution.

Answers 1) 5.3 x 10-3 M • 1.8 x 10-3 M • 3.0 x 10-2 M

Equations (no need to memorize them) • Kw = [H3O+] [OH-] where Kw = 1.0 x 10-14 • pH = -log[H3O+] • pOH = -log[OH-] • pH + pOH = 14 • [H3O+] = antilog(-pH)

pH Calculations • Determine the [H3O+] and [OH-] in a 0.01 M solution of HClO4. • An aqueous solution of NaOH has a [H3O+] of 1 x 10-11 M. What is the [OH-]? • Determine the pH of a 1 x 10-4 M solution of HBr.

Answers • [H3O+] = 0.01 M, [OH-] = 1 x 10-12 • 1 x 10-3 M • 4

pH Calculations • Determine the pH of a 5 x 10-4 M solution of KOH. • What is the pH of a solution whose [H3O+] = 6.2 x 10-9 M? • Determine the pH of a 0.00074 M solution of NaOH.

Answers • 10.7 • 8.21 • 10.9

pH Calculations • What are the [H3O+] and [OH-] of a solution if its pH = 9.0? • The pH of a solution is 10.0. What is the concentration of hydroxide ions in the solution? • The pH of a hydrochloric acid solution for cleaning tile is 0.45. What is the [H3O+] in the solution?

Answers • [H3O+] = 1 x 10-9 M, [OH-] = 1 x 10-5 M • 1 x 10-4 M • 0.35 M

pH Calculations • A shampoo has a pH of 8.7. What are the [H3O+] and [OH-] in the shampoo?

Answers 1. [H3O+] = 2 x 10-9 M, [OH-] = 5 x 10-6 M

Chapter 14 and 15 Review