acids and bases

Chemistry Acids and Bases Review Sheet

Chapter 13:

1. Understand the following terms:

-Disassociation

-Ionization

-Strong electrolyte

-Weak electrolyte

2. Be able to write a net ionic equation and determine if a precipitate forms (Ex: Will a

precipitate form if solutions of barium chloride and sodium sulfate are combined? If so write a

net ionic equation).

3. Understand how to calculate molarity and moles of various equations.

Chapter 14:

1. Understand the properties of both acids and bases

2. be able to name binary acids and oxyacids

-HCl H 2 S

-HNO 3 H 2 CO 3

-HNO 2 HBr

3. Understand the definition of an acid and base according to:

-Arrhenius

-Bronsted-lowry

4. Understand what makes a strong and weak acid or base and be familiar with the strong acids

and bases.

5. Be able to write a reaction between an acid and a metal and determine if a reaction will

occur.

6. Understand how to write the reaction between an acid and base.

7. Know in which direction an acid/base reaction will occur. (aka, understand the concept of

conjugate acids and bases as well as their relative strengths)

Chapter 15:

1. Know how to perform all the calculations on the practice sheet (finding concentrations of

H3O+ or OH-, determining pH, Determining [H3O+] or [OH-] if given pH)

2. Understand what the pH scale signifies and what pOH stands for.

3. Understand how to calculate the molarity or pH of a solution when performing a titration. Ex:

By titration, 17.6 mL of H 2 SO 4 neutralized 27.4 mL of 0.0165 M LiOH solution. What is the

molarity of the aqueous acid solution?

4. Understand how to perform a titration and determining the equivalence point pH between

strong and weak acids and bases.

Unit 7

Part 1: Ions in Aqueous Solutions

Dissociation

When an IONIC substance is mixed in water, it

breaks apart into ions. This is called dissociation.

NaCl + H2O 🡪 Na+ + Cl-

BaF2 🡪 Ba2+ + 2F-

Al2(SO4)3 🡪 2Al3+ + 3SO42-

Ionization

When a COVALENT compound (most acids) mixes

with water it reacts with the water to form ions

HCl + H2O 🡪 H3O+ + Cl-

HF + H2O 🡪 H3O+ + F-

H2SO4 + 2H2O 🡪 2H3O+ + SO42-

Hydronium Ion

Complete the following reactions and

label them as dissociation or Ionization.

LiOH + H2O 🡪

HI + H2O 🡪

BaBr2 + H2O 🡪

Li2CO3 + H2O 🡪

Li+ + OH- Dissociation

H3O+ + I- Ionization

Ba2+ + 2Br- Dissociation

2Li+ + CO32- Dissociation

Solubility Rules

Used to determine if an ionic substance will dissolve in water

Determine if the following will be

soluble

NaBrO3

CaSO4

AgBr

FeCO3

V(NO3)2

Soluble: big momma

Insoluble

Soluble: big momma

Insoluble

Determine if the following is soluble or

insoluble:

ZnSO4

AgClO3

LiOH

AgCl

Soluble: big momma

Soluble: SO4

Insoluble

Net Ionic Equations

Equations showing only reacting ions

Steps for writing them

1) Write a balanced equation

2) Break apart anything that is aqueous into

ions

3) Cancel anything that appears on BOTH

sides

4) Write the final product

Write a net ionic equation for the reaction between

aqueous ammonium sulfide and aqueous cadmium

nitrate to yield aqueous ammonium nitrate and solid

cadmium sulfide.

(NH4)2S(aq) + Cd(NO3)2(aq) 🡪 CdS(s) + 2NH4NO3(aq)

2 NH4+ + S2- + Cd2+ + 2 NO3- 🡪 CdS(s) + 2NH4+ + 2NO3-

S2- + Cd2+ 🡪 CdS(s)

Will a precipitate form?

When writing the products of a reaction,

anything that is insoluble will form a

precipitate (solid)

Anything you cross out is called a spectator

ion.

If none of the products are insoluble: you

can’t write a net ionic equation!

Will a reaction occur? If so write a net

ionic equation.

2NaOH(aq) + Li2CO3(aq) 🡪

NaCl(aq) + AgClO4(aq) 🡪

Na2CO3 + 2LiOH

Soluble = (aq)

NaClO4 + AgCl

Soluble = (aq)

Insoluble = (s)

Na+ + Cl- + Ag+ + ClO4- 🡪 Na+ + ClO4- + AgCl(s)

NO REACTION

Ag+ + Cl- 🡪 AgCl(s)

Write the reaction between aqueous lithium sulfate and

aqueous barium chloride. Determine if a precipitate will

form, if so, write a net ionic equation

Li2SO4(aq) + BaCl2(aq) 🡪 2LiCl + BaSO4

2Li+ + SO42- + Ba2+ + 2Cl- 🡪 2Li+ + 2Cl- + BaSO4(s)

Ba2+ + SO42- 🡪 BaSO4(s)

Part 2: Acids and Bases

Strong vs Weak Electrolytes

Strong electrolyte: a substance that fully ionizes

or dissociates in water.

HCl + H2O 🡪 H3O+ + Cl-

1 mole

1 mole 1 mole

Since HCl is a strong electrolyte every molecule of

HCl breaks apart into hydronium and chloride ions.

Weak electrolyte: Does NOT fully ionize or

dissociate in water

Fe(OH)2 + H2O 🡪 Fe2+ + 2OH-

1 mole

0.000001 mol of each

Since Fe(OH)2 is a weak electrolyte, very few of the

molecules break apart in water.

Acids

A substance that when dissolved in water, increases

the concentration of hydrogen ions (H+) or

hydronium ions (H3O+)

Taste sour

Turn blue litmus paper red

Consist of a H bonded with a non-metal or a H bonded

with a polyatomic ion.

HCl, HI, HNO3, H2SO4, HCH3COO

Naming Acids

Binary acids: H and ONE other element

HCl, HF, HI, HBr, H2S

Hydro - (nonmetal)- ic acid

HCl = hydrochloric acid

HBr = Hydrobromic acid

HF = Hydrofouric acid

Acids with polyatomic ions

If the PAI ends in “ate” you name it as (polyatomic ion - ate) + ic

acid

If The PAI ends in “ite” you name it (polyatomic ion -ite) +ous acid

HNO3 = nitric acid

HNO2 = nitrous acid

H2SO4 = sulferic acid

H2SO3 = Sulferous acid

HClO4 = perchloric acid

HClO3 = chloric acid

HClO2 = Chlorous acid

HClO = hypochlorous acid

Strength of Acids

Strong acids are strong electrolytes.

HCl, HBr, HI, HNO3, H2SO4, HClO4, HClO3

These acids fully IONIZE in a solution

Weak acids are weak electrolytes

They do not fully ionize in a solution

Any acid not mentioned before.

Name the following acid and

determine if it is strong or weak

HBr

HCH3COO

H2CO3

H3P

Hydrobromic acid

Strong

Acetic acid

Weak

Carbonic acid

Weak

Hydrophosphoric acid

Weak

Bases

Substances that increase the hydroxide ion concentration in

a solution (OH-) or decease the H+ concentration

Taste bitter

Turn red litmus blue

Typically consist of a metal with a OH or an NH3 or NH2…

NaOH, KOH, Ba(OH)2, NH3, CH2NH2

Strong and Weak bases

Weak bases are weak electrolytes

All organic amino compounds (CH bound with

NH2)

NH3

Most metal hydroxides except…

Strong bases are strong electrolytes

Group I hydroxides

Ba, Sr, Ca Hydroxides

Acid base reactions

Acids react with metals in a single

displacement to make a salt and hydrogen gas

HCl + Na 🡪 NaCl + H2

Acids and bases react to form water and a

salt (double displacement).

HCl + NaOH 🡪 NaCl + H2O

Bronsted Lowry Acids and Bases

Acid: any substance that donates a proton

(H+) in a reaction.

Base: any substance that accepts a proton in a

reaction.

HCl + H2O 🡪 H3O+ + Cl-

Acid

Base

Determine the Bronsted Lowry Acids

and Bases

HF + NH3 🡪 NH4+ + F-

H2O + CH2NH2 🡪 OH- + CH2NH3+

H2O + H2SO4 🡪 H3O+ + HSO4-

Acid

Base

Acid

Base

Conjugate Acid Base Pairs

With Bronsted Lowry acids and bases, every

acid has a conjugate base pair and each base

has a conjugate acid pair.

HCl + H2O 🡪 H3O+ + Cl-

Acid

Base

Conj. Acid

Conj. Base

Identify the conjugate acid base pairs

HSO4- + OH- 🡪 SO42- + H2O

NH3 + HCH3COO 🡪 NH4+ + CH3COO-

HBr + H2O 🡪 H3O+ + Br-

Strength of CA and CB

The conjugate acid of a strong base is weak

The conjugate acid of a weak base is stronger

that that base

Same for acids

HI 🡪 I-

HI is a strong acid so I- is a weaker conjugate base

NH3 🡪 NH4+

NH3 is a weak base so NH4+ is a stronger acid (not a

strong acid)

HF 🡪 F-

HF is a weak acid so F- is a stronger base (not a

strong base).

Reactions will always go from the

stronger side to the weaker side

HBr + H2O 🡪 H3O+ + Br-

Strong acid

Weaker

Direction of reaction 🡪

HCH3COO + H2O 🡪 H3O+ + CH3COO-

Weak acid

Stronger

Direction of reaction 🡨

Part 3: pH and Titrations

Measure of the Hydronium ion concentration in a

solution

It is a log scale

From 0 = very acidic

To 14 = very basic

pH 7 = neutral

Figure 3.UN05

Acidic

[H+] > [OH−]

Neutral

[H+] = [OH−]

Basic

[H+] < [OH−]

Bases donate OH−

or accept H+ in

aqueous solutions

Acids donate H+ in

aqueous solutions.

Calculating pH

pH + pOH = 14

pH = -log[H3O+]

pOH = -log[OH-]

[H3O+][OH-] = 1*10-14

[H3O+] = 10-pH

[OH-] = 10-pOH

Steps for calculating pH

[] = concentration in molar.

You should always make sure you do an

ionization or dissociation reaction and then

find [] of OH or H3O first.

Use a combination of reactions to solve the

problem.

Find the pH of a 1*10-3 M solution of

HCl?

HCl + H2O 🡪 H3O+ + Cl-

1*10-3 M

: 1*10-3 M

2) pH = -log[H3O] = -log [1*10-3 M]

pH = 3

Find the pH of a 1.0*10-7M solution of

Ba(OH)2

Ba(OH)2 🡪 Ba2+ + 2OH-

1.0*10-7M : 2(1.0*10-7M)

pOH = -log[OH-] = - log[2.0*10-7M]

pOH = 6.7

pH + pOH= 14

pH = 14- 6.7 = 7.3

Find the [H3O+] of a 1.4*10-4M

solution of NaOH.

NaOH 🡪 Na+ + OH-

1.4*10-4 : 1.4*10-4

[H3O+][OH-] = 1*10-14

1*10-14/[OH-] = [H3O+]

1*10-14/ 1.4*10-4 = 7.1 *10-11

Find the [OH-] of a acetic acid solution

with a pH of 4.6

[OH-] = 10-pOH

14- pH = pOH = 14-4.6 = 9.4

[OH-] = 10-9.4

[OH-] = 3.98*10-10

Titrations

A method of

determining the

molarity of a solution.

An acid is added to a

base (or vice versa) until

the endpoint is reached.

An indicator is used to

determine when the

endpoint is reached.

Indicator

A substance that changes colors at certain pH

values.

For example: phenophthalene indicator

Acidic

Basic

End Point

When the acid and base both fully react, the

equivalence point is reached. After this point

1 drop of either the acid or base will make

the indicator change color. This is called the

end-point!

For a strong acid and base, the equivalence

point will be at a pH of 7.

Calculations with Titrations

A 0.500M solution of NaOH is titrated with a solution of

HCl of unknown molarity. If it takes 25mL of NaOH to

fully react with 70 mL of HCl, find the molarity of the

HCl solution.

Write a balanced equation:

NaOH + HCl 🡪 NaCl + H2O

2) Find the moles of the known value:

M = mol/L so for NaOH = moles = M*L = 0.500 * 0.025L = .0125moles NaOH

3) Use ratio to find the moles of the unknown:

Ratio of NaOH : HCl

1 : 1

0.0125 mol : x x = 0.0125 moles of HCl

4) Find molarity

M= moles/L

= 0.0125/ 0.070L = 0.179M of HCl

A 15.5 mL sample of 0.215M LiOH solution is

required to titrate 21.2 mL of acetic acid solution.

Find the molarity of the acetic acid solution.

Write a balanced equation:

LiOH + HCH3COO 🡪 LiCH3COO + H2O

2) Find the moles of the known value:

M = mol/L so for LiOH = moles = M*L = 0.215 * 0.0155 L = 0.0033 moles LiOH

3) Use ratio to find the moles of the unknown:

Ratio of LiOH : HCH3COO

1 : 1

0.0033 mol : x x = 0.0033 moles of HCl

4) Find molarity

M= moles/L

= 0.0033/ 0.0212L = 0.157M