Acid and Base Notes Acids + Base <=> Salt + water

HCl + KOH <=> KCl + H2O

What are the observable properties of acids, bases, and neutral compounds?

Property Acid Base Neutral

concentration Hydromium [H3O

+] or

[H+] ions Hydroxide [OH-] [H3O

+] = [OH-]

pH 0-6 8-14 7

chemistry

Corrosive – strong acids

can burn skins and

break down metals

Caustic – strong bases can

break down and damage

tissue

None- just like salts

Dissociation H+X- H++ X- Y+OH-

Y+ + OH- none

Litmus indicator Turn into red Turn into blue No change

Phenolphthalein colorless pink No change

taste sour (lemon or vinegar) bitter (baking soda, Alka

Seltzer)

sweet, salty, bitter, no

flavor

smell may burn nose usually none (except NH3) none, or a “chemical

smell”

reactivity React with metals to

form H2 gas Do not react well with metals varies by compound

conductivity

Acids are good

electrolytes and conduct

electricity well

Only strong bases are good

electrolytes; bases do not

conduct electricity well

Some do

texture of solution sticky slippery/soapy oily, sticky, watery,

slippery

Acids Bases

Strong 100 % dissociation into H+ in water

e.g. HCl, HNO3, H2SO4

100 % dissociation into OH- in water

e.g. LiOH, NaOH, KOH,

Weak Partial or no dissociation into H+ in water

e.g. HCH3COO, HF

Partial or no dissociation into OH- in water

e.g. NH3 (no OH-), NH4OH

Concentrated High [H+], pH = 0-1 High [OH-], pH = 13-14

Diluted Low [H+], pH = 5-6 Low [OH-], pH = 8-9

What are the different definitions of acids and bases?

Arrhenius acids:

Acids give off H+ ions (called “hydronium ions” “H3O+”, or proton H+) in water

They always start with the letter “H” at the front (except CH3COOH or HCH2COO)

Examples: Nitric acid (HNO3), hydrochloric acid (HCl), sulfuric acid (H2SO4).

Arrhenius Bases:

Bases give off hydroxide ions (OH- ions) in water

They contain the hydroxide ion (OH) at the back

Examples: Ca(OH)2, NaOH

Brønsted-Lowry acids:

H+ donor

HX H+ + X-

Acid H+ donor + conjugate base

(A) H+ + (CB)

HNO3 H+ + (NO3)-

H2SO4 2 H+ + (SO4)2-

Brønsted-Lowry bases:

H+ receiver

Y- + H+ HY

Base + H+ receiver conjugate acid

(B) + H+ (CA)

NH3 + H+ (NH4)+

HSO4- + H+ H2SO4

Strong / Weak Acids and Bases Notes

Weak Acids and Bases Examples

WEAK ACIDS WEAK BASES

HF – hydrofluoric acid NH3 – ammonia gas

CH3COOH or HCH3COO – acetic acid Every base other than the 8 SB

Every acid other than the 7 SA

Examples

pH Notes

pH -- a measure of how acidic or basic a solution is.

Acids pH = 0-6.99 Neutral pH = 7.0 Bases pH = 7.01-14

pH of Common Acids

0 - Hydrochloric Acid (HCl)

1.0 - Battery Acid (H2SO4 sulfuric acid)

2.0 - Citrus juice / Lemon Juice

2.2 - Vinegar

3.0 - Apples

4.0 - Wine and Beer

4.5 - Tomatoes

6.6 - Milk

pH of Common Bases

7.4 - Human Blood

8.3 - Baking Soda (Sodium Bicarbonate)

9 – Soap

10.5 - Milk of Magnesia

11.0 - Ammonia

12.4 - Lime (Calcium Hydroxide)

13.0 - Lye

14.0 - Sodium Hydroxide (NaOH)

pH of Neutral Compounds (e.g. water) = 7.0

pH Calculations

Given: [H+], find pH:

pH = -log [H30+] = -log [H+]

Example 1: 0.0035 M HCl, pH=?

HCl = 1 H+ [H+] = 0.0035 M

pH = -log [H+] = -log (0.0035M)

= 2.455931956 = 2.46

Example 2: 3.50 x 10-3 M H2SO4, pH = ?

H2SO4 2 H+ [H+] = 2 x 0.0035 M = 0.0070 M

pH = -log [H+] = -log (0.0070M)

= 2.15490196 = 2.15

Given: pH, find [H+]:

[H+] = 10-pH

Example 1: pH of a solution = 2.46, [H+] = ? M

[H+] = 10(-2.46) = 0.003467369

= 3.467369 x 10-3 = 3.47 x 10-3 M

Example 2: pH of a solution = 2.15, [H+] = ? M

[H+] = 10(-2.15) = 0.007079458

= 7.079458 x 10-3 = 7.08 x 10-3 M

pH, pOH, [H+], and [OH-] Calculation Chart

1. pH = -log [H+] pOH = -log [OH-]

2. [H+] = 10(-pH) [OH-] = 10(-pOH)

3. pH + pOH = 14.00

4. pH: 0-6.99 = acidic

5. pH: 7.00 = neutral

6. pH: 7.01 – 14.00 = basic

7. pH and pOH: no unit

8. [H+] and [OH-]: unit = M (concentration or molarity)

Oxidation Number Rules

The oxidation state of… Summary Examples

1) Group 1 in compound is +1 Group 1 in compound: +1 NaCl: Na +1

2) Group 2 in compound is +2 Group 2 in compound: +2 Mg(OH)2: Mg +2

3) An atom in an element is zero Element: 0 Na, O2, O3, Hg, Cl2, Mg 0

4) Neutral compound: the sum of all ON is

0

Neutral compound -> sum: 0 NaCl all added up = 0

MgCl2 -> all added up = 0

5) Monatomic ion: the same as its charge Monatomic ion : charge of ion Na+ (+1)

Cl- (-1)

6) Polyatomic ion: the sum of all ON is its

charge

Polyatomic ion -> sum: charge (PO4)3- all added up = -3

(OH)- all added up = -1

7) Hydrogen in covalent compound is +1 Hydrogen: +1 H2O: H -> +1

NH3: H -> +1

8) Oxygen in compound is -2

Exception: peroxide O22- oxygen is -1

Oxygen: -2

Except O22-

O = -1

CO2: O -> -2

H2O2: O -> -1

Na2O2: O -> -1

9) Fluorine in compound is -1 Fluorine: -1 PF3: F -1

Na Br 2Na 2Na+ + 2e- Br2 + 2e- 2Br-

Na loses e- because e- are

on the right side of the

equation

Br gains e- because e-

are on the left side of

the equation

Na oxidation number

increases from 0 to +1

Br oxidation number

decreases from 0 to -1

Na is oxidized Br is reduced

Na is reducing agent Br is oxidizing agent

Na can reduce Br Br can oxidize Na

Na: Br:

Add two half equations: 2 Na 2 Na+ + 2 e-

Br2 + 2e- 2 Br- .

Redox Equation: 2 Na + Br2 2 Na+ + 2 Br-

2 Na + Br2 2 NaBr