Acids & Bases chapter15

6 acidsSulfuric H2SO4

Nitric HNO3

Hydrochloric HCl

Phosphoric H3PO4 …cola

Carbonic H2CO3

Acetic Acid HC2H3O2 …vinegar

What do you notice?

What makes an acid an acid?

HCl + H20 H+ + Cl-

Acids … ionize themselves… break apart into their ions.

Remember water is very polar

H20 + HCl H30+ + Cl-

You may see…either….. H30+ or H+

These have names: hydronium ion, , hydrogen ion, , proton ion.

BasesSodium Hydroxide NaOH

Magnesium Hydroxide Mg(OH)2

Aluminum Hydroxide Al(OH)3

Ammonia NH3

Sodium Hydrogen Carbonate NaHCO3

What do you notice?What makes a base a base? (OH) or the ability to make an (OH)

Base solutions are sometimes called ALKALINE SOLUTIONSBases dissociate ….. Break apart producing hydroxide

NaOH + H20 Na+ + OH-

NH3 + H20 NH4+ + OH-

Strong vs. Weak p.460 & p. 469

Can tell 2 ways memorize them

arrows

HX + H20 H30+ + X- label

Strong acids: HCl, H2SO4, HNO3 ionize completely

Weak acids: H2CO3, HC2H3O2, H3PO4

Strong Base: group 1 or 2 metal hydroxidesWeak base: NH3 dissociates completely

HF + H20 F- + H30+

H2SO4 + H20 HSO4 + H30+

Strength of acids

depends on: H+ production

polarity of bonds

ionization

The greater the polarity of bond = greater strength

The greater the ionization = greater strength

Strong acids= HCl, HNO3, H2SO4

Weak Acid = H3PO4, H2CO3, HC2H3O2

Notice: strength of acid does not depend on number of hydrogens

Strength of bases depends on: OH- production

polarity of bonds dissociation of hydroxide

The greater the polarity of bond = greater strengthThe greater the dissociation = greater strength

Base solutions are sometimes called alkaline solutions

Strong Bases: NaOH, KOH, Ca(OH)2, Ba(OH)2

Weak Base: NH3

Note: Alkali metals are stronger than alkaline earth….why?

Strong Acid/ Strong Base = Strong electrolyte……..why?

pH Scale pH measures [concentration] of H30+ or OH-

pH ….. O – 14

0 3 7 10 14

Units of 10

4.6 pH is 10x stronger than 5.6pH

4.6 pH has 10x [H30] than 5.6 pH

Pure water is neutral…..pH 7

“self-ionization of water

Water produces ½ H+ and ½ OH-

[H+]

[OH-]

20 minute lab

Red litmus paper turns blue in base

Blue litmus paper stays blue in base

Determine pH using the rainbow chart

pH = [H30+] or [H+] pH = power of the Hydrogen

Calculating pH from concentrations

pH = -log [H3O+]

pOH = -log [OH-]

pH + pOH = 14 ws.17.24

Calculator

number exponentFind pH of a solution of hydronium concentration of [3 x 10-5]?

pH = -log [3 x 10-5]

3 -5 =

(-) log

Yellow

2nd EE

(-) log Yellow

2ndEE

[1 x 10-3 M] HCl

[1 x 10-5 M] HNO3

[0.001 M ] HCl

[0.09 M ] HBr

[1.34 x 10-4M] HCl

[7.98 x 10-2 M] HNO3

Calculate pH

pH + pOH = 14

ph pOH

2 =14

8 =14

6 =14

13 =14

4 =14

7 =14

Find the pH of a solution of Hydroxide concentration of [3 x 10-5]

(-)log 3 -5 =

BUT it is hydroxide so…..it is the pOH….so subtract it from 14.

Yellow2nd EE

Calculate pH

[1 x 10-4 M] NaOH

[1 x 10-3 M] KOH

[1 x 10-6 M] LiOH

[3.2 x 10-2 M] Mg(OH)2

[0.08 M] Ca(OH)2

Calculate pH

Hydronium concentration of [.001M]

Hydroxide concentration of [.001 M]

H+ concentration of [ 1 x 10-5 M]

OH concentration of [1 x 10-5 M]

Ws.14.1

Ws.17.26

1. A popular soda pop drink is measured to have a hydronium concentration of 1.34 x 10-4. What is the pH and is it acidic, base or neutral?

2. The molarity of hydroxides in a pancake syrup is

1.0 x 10-8M. Pancake syrup by law must have a pH lower than 7 to be sold in the open market. Calculate the pH and identify if acid, base, neutral. Can it be sold?

3. You work for Colgate Toothpaste. You need to make stannic fluoride solution of hydroxide molarity [2.44 x 10-4]. What is the ph? Is it acid, base, neutral?

If pH is 7.40 what is the [hydronium] or the molarity?

“If given pH…find antilog”negative # = [hydronium conc.]

-7.40 = [.00000004] or [4 x 10-

8]

“secret….hydronium concentration is the molarity ”

BUT::::: if they also ask for hydroxide concentration one must use the equilibrium

constant for water:::::::::

Equilibrium Constant for water is

Kw = [H+] [OH-]

Kw = [1 x 10-7] [1 x 10-7]

Kw = 1 x 10-14

Yellow2nd log

1. The pH of an orange is 4.0pH. What are the [H30] and [OH] in this fruit? What is its Molarity?

2. Lemons have a pH 3.15. What are the hydronium and the hydroxide concentrations? What is its molarity?

3. What is the molarity of pH is 12.9 for a Calcium hydroxide solution?

Remember: 3 formulas: pH=-log[H3O]

pOH=-log[OH]

pH + pOH = 14

Remember: [H3O] is hydronium concentration

or…..molarity for an Acid

or…..H+ proton concentration

Remember: [OH] is hydroxide concentration

or molarity for a base

Remember: if given pH use antilog to calculate [H3O] [OH]

put pH in as negative number

Remember: Kw = [H3O] [OH] = 1x10-14

Kw = [1x10-7] [1x 10-7]

Kw = 1x10-14

Neutralization Reaction

p.474

Strong acid + Strong Base salt + water Look on reference table: 4c

HCl + H20 H+ + Cl-

NaOH + H20 OH- + Na+

Put them together

HCl + NaOH NaCl + H2O

Salt: a compound composed of

a cation+ from an base

and an anion- from a acid.

Stomach Ache CaCO3 ….tums

HCl + Mg(OH)2 …milk of magnesia

NaCO3 …. Rolaids

Neutralize …………..salt + H20

HCl + CaCO3 CaCl + CO2 + H20

HCl + Mg(OH)2 MgCl + H20

HCl + NaCO3 NaCl + CO2 + H2O

Which will make you burp?

Tums and Rolaids… that is why old people prefer milk of magnesia

Titration: the controlled addition and measurement of

the amount of a solution of known concentration

required to react completely with a

measured amount of a solution of unknown concentration p.497

Equivalence point: The point at which the two solutions used in a titration are present in chemically equivalent amounts p. 498

Indicator: an organic substance that changes color whether in

acid or base…….Phenolphthalein

Calculating Titration Problems ws 19-3

On your reference sheet nM1V1 = nM2V2

n = # of (H) or (OH) in the molecule

Ws 19-3

1. A volume of 30mL of 0.25M HCl neutralizes a 50mL sample of KOH solution. What is the concentration of KOH? Create new copyrght

6. A volume of 50mL of 0.30M HCl neutralizes a 60mL sample Ca(OH)2 solution. What is the concentration of Ca(OH)2?

2 acid / base theories

Arrhenius acids & bases p. 459

Arrhenius acid = a chemical that increases H+ ions.

Arrhenius base = a chemical that increases OH- ions

“limited because must be in water….not everything in water..p.464”

Bronsted-Lowery acids & bases p.464

Bronsted-Lowery acid = a chemical that is a proton donor (H+)

Bronsted-Lowery base = a chemical that is a proton acceptor (H+)

“ notice no mention of OH”

Conjugate acid/ base the species that forms in result of gaining or losing a proton (H+)

acid base

Arrhenius H+donor OH- producer

Bronsted-Lowery H+donor H+ acceptor

Overhead worksheet 15.2,3,, 15.4

Overhead 88 , 87 quick lab

Remember Equilibrium Keq = [conc] [conc] ….(g) and (aq) but not liquids nor solids

Equilibrium Constant for water is Kw = [H+] [OH-]Kw = [1 x 10-7] [1 x 10-7]Kw = 1 x 10-14

On chemistry table….constant like.. pie = 3.14 r = .0821

We can use this constant (Kw = 1 x 10-14) to calculate pH of a solution

Ws problems 17.