acids always have as the state and always have a. naming acids and bases 6.1 theories of acids and...

acids always have as the state and always have

A. Naming Acids and Bases 6.1 Theories of Acids and Bases

Chapter 6: Acids & Bases

Rules1. hydrogen becomes acid2. hydrogen becomes acid3. hydrogen becomes acid

____ide hydr____ic_____ate _____ic____ite ____ous

(aq)hydrogen

**Hydro and his side kick were skating, when they ate shit on ice, and became a little less rite chous.

Examples:

hydroiodic acid

phosphoric acid

nitrous acid

sulphurous acid

Change each of the following to the appropriate acid name and give the formula:

HI(aq)

H3PO4(aq)

HNO2(aq)

H2SO3(aq)

1. hydrogen iodide =

2. hydrogen phosphate =

3. hydrogen nitrite =

4. hydrogen sulphite =

most bases are ionic compounds that are named accordingly

Examples:

sodium hydroxide

sodium hydrogen carbonate magnesium hydroxide

ammonia

Name each of the following bases:

1. NaOH(aq) =

2. NaHCO3(aq) =

3. Mg(OH)2(aq) =

4. NH3(aq) =

IUPAC names for acids and bases are simply the word “aqueous” followed by the ionic name

Examples:

aqueous hydrogen iodide

aqueous magnesium hydroxide

aqueous hydrogen sulphite

aqueous sodium hydrogen carbonate

Write the IUPAC name for each of the following acids and bases:

1. hydroiodic acid =

2. magnesium hydroxide =

3. sulphurous acid =

4. sodium hydrogen carbonate =

B. Properties of Acids and Bases are

of a substance empirical properties observable properties

acids, bases and neutral substances have some properties that distinguish them and some that

are the same

Acids Bases Neutral Substances

sour bitter

electrolytes electrolytes electrolytes, non-electrolytes bases acids

indicators indicators do not

H2(g)

eg)HCl(aq), H2SO4(aq)

eg)NaCl(aq), Pb(NO3)2(aq)

eg) Ba(OH)2(aq) NH3(aq)

less than 7

greater than 7

of 7

litmus - litmus - bromothymol blue - bromothymol blue

-

red blue blue yellow

taste taste

neutralize neutralize

react with react with

react with to produce

metals

phenolphthalein - phenolphthalein - colourless

pink

affect indicators the same way

pH pH pH

first proposed theory on acids and bases

his theory was that some compounds form

his explanation of the properties of acids and bases is called the

electrically charged particles

Svante Arrhenius

Arrhenius theory of acids and bases

C. Arrhenius Definition

when in solution

an Arrhenius is a substance that to form in water

a will in an aqueous solution

base increase the [OH-(aq)]

base dissociateshydroxide ions, OH(aq),

an Arrhenius is a substance that (because it is molecular) to form

an will in an aqueous solution

acid increase the [H+(aq)]

acid ionizes hydrogen ions, H+(aq), in water

D. Modified Arrhenius Definition the original definition of acids and bases

proposed by Arrhenius is good but it has

some substances that might be predicted to be are actually

limitations

neutral basic

it has been found that not all bases contain the

eg) Na2CO3(aq), NH3(aq)

hydroxide ionas part of theirchemical formula

an Arrhenius is a substance that

in aqueous solution

base (modified)reacts with water

NH3(aq)eg)

OH(aq)+NH4+(aq)H2O()+

to produce OH(aq) ions

it has been found using analytical technology like X-ray crystallography that in an aqueous solution

when acids ionize, they produceH+(aq)eg) HCl(g) H+(aq) + Cl(aq)

H+(aq) ions do not exist in isolation

the hydrogen ion is extremely positive in charge and water molecules themselves are very polar so… it is that would exist in water without being attracted to the

of other

highly unlikely hydrogen ions

negative poles water molecules

H3O+

(aq)

this results in the formation of the hydronium ion

+Hydrogen ion

Water molecule

an Arrhenius is a substance that

in aqueous solution

acid (modified)reacts with water

HCl(aq) eg)

H3O+(aq) +Cl(aq)H2O()+

H2SO3(aq)

H3O+(aq) +HSO3

(aq) H2O()+

to produce H3O+(aq) ions

Review: Definitions of Acids and BasesReview: Definitions of Acids and BasesInitial Arrhenius Acid and Base Acids dissociate to form H+ ions

in a solution. Ex: HCl (aq) = H+

(aq) + Cl- (aq)

Bases dissociate to form OH- ions in a solution.

NaOH(aq) = OH- (aq) + Na+

(aq)

Wrong for bases that don’t finish with OH – doesn’t explain a few bases….

Modified Arrhenius Acid and Base Acids react with water to form

H3O+ ions in a solution. Ex:

Bases react with water to form OH- ions in a solution. (Only for bases that don’t finish with OH)

Practice a few!!!Practice a few!!!

Dissociate these acids and bases HNO3 (aq) + H2O (l)

HCOOH (aq) + H2O (l)

the of a substance depend on two things:

acidic and basic properties

1. the of the solution

2. the of the acid or base

6.2 Strong and Weak Acids and Bases

concentration

identity

A. Strong Acids and Weak Acids

an acid that ionizes almost in water is called a

100% of the becomes

strong acid100%

eg) HCl(aq) + H2O() Cl(aq)+H3O+(aq)

HCl(aq) H3O

+(aq) and Cl(aq)

the concentration of the is the as the concentration of the it came from

H3O+(aq) same

acid

strong acids are strong electrolytes andreact vigorously with metals

there are 6 strong acids:

HNO3(aq)

H2SO4(aq)

HCl(aq)

HI(aq)

HBr(aq)

HClO4(aq)

nitric acid

sulfuric acid

hydrochloric acid

hydroiodic acid

hydrobromic acid

perchloric acid

***on your periodic table

a and only a small percentage of the acid formsweak acid does not ionize 100%

react much less vigorously with metals

ions in solution

we use the for weak acids

eg)

CH3COOH(aq) + H2O()⇌ CH3COO(aq)+H3O+(aq)

equilibrium arrow

weak acids are weak electrolytes and

B. Strong Bases and Weak Bases

a base that dissociates into ions in water is called a

are strong bases

strong base100%

a and only a small percentage of the base forms

we use the for weak bases

ionic hydroxides and metallic oxides

eg) NaOH(aq) OH(aq)+Na+(aq)

ions in solution

weak base does not dissociate 100%

eg) NH3(aq) + H2O() ⇌ OH(aq)+NH4+(aq)

equilibrium arrow

C. Monoprotic and Polyprotic Acids

acids that have only per molecule that can are called

monoprotic acids can be

eg) CH3COOH(aq)HNO3(aq),HF(aq),HCl(aq),

strong or weak

one hydrogen atomionize

monoprotic acids

acids that contain that can are called

eg) H3PO4(aq)H2SO4(aq),

acids with are , with are

two hydrogens diproticthree hydrogens triprotic

two or more hydrogen atomsionize polyprotic acids

when polyprotic acids ionize, only hydrogen is removed at a time, with each acid becoming

one

progressively weaker

eg)

HSO4(aq)

HSO4(aq)+H3O

+(aq)

SO42(aq)+H3O

+(aq)H2O()+

H2O()+H2SO4(aq)

D. Monoprotic and Polyprotic Bases

bases that are called

bases that react with water in are called

eg) NaOH(s)

react with water in only one step to form hydroxide ions monoprotic bases

two or more stepspolyprotic bases

eg) CO32(aq), PO4

3(aq)

***complex ions with more than 1- charge!!!

as with polyprotic acids, only

eg)

HCO3(aq)

HCO3(aq)+OH(aq)

H2CO3(aq) +OH(aq) H2O()+

H2O()+CO32(aq)

one OH(aq) is formed at a time, and each new base formed is than the last

weaker

E. Neutralization

the reaction between an acid and a base produces an

the products of are both

ionic compound and water

neutralneutralization

in a neutralization reaction or between a , the product is alwayswater

strong acid and a strong baseacid-base reaction

H3O+

(aq)2 H2O()OH(aq)+

water acid + base → a salt +

eg) HCl(aq) + KOH(aq) →KCl(aq) + HOH()

F. Acid and Base Spills there are many uses for both acids and bases

in our households and in industry

due to their, special care must be used when they are being

reactivity and corrosiveness produced and transported

the two ways to deal with acid or base spills are: 1. dilution:

2. neutralization:

reduce the by adding

you always use a for the neutralization so you aren’t left with another hazardous situation

concentrationwater

weak acid or base

A. Ion Concentration in Water the “self-ionization” of water is very small

(only 2 in 1 billion)

H3O+(aq) OH-(aq) + +H2O()H2O()

hydronium ionshydroxide ions equal and constant in pure water

[H3O+(aq)]=

[OH-(aq)] =

1.0 x 10-7 mol/L

1.0 x 10-7 mol/L

the concentration of and are

6.3 Acids, Bases and pH

B. The pH Scale

in 1909, Soren Sorenson devised the

it is used because the [H3O

+(aq)] is

pH scale

very small

at 25C (standard conditions), most solutions have a pH that falls between0.0 and

it is possible to have a pH and a pH

it is a based on whole numbers that are powers of 10

logarithmic scale

14.0

negativeabove 14

there is a for every change in on the pH scale

10-fold change in [H3O+

(aq)]

a solution with a pH of 11 is times more basic than a solution with a pH of 9

10 10 = 100

pH Scale

0 7 14

more acidic more basic

neutral

1

eg)

Try These:

1.     [H3O+(aq)] = 1 x 10-10 mol/L pH =

2.     [H3O+(aq)] = 1.0 x 10-2 mol/LpH =

3.     [H3O+(aq)] = 6.88 x 10-3 mol/L pH =

4.     [H3O+(aq)] = 9.6 x 10-6 mol/LpH =

pH = log [H3O+

(aq)]

10

2

2.1

5.0

C. Calculating pH and pOH

***New sig dig rule: when reporting pH or pOH values, only the numbers to the count as significant

right of the decimal place

Example6.30 g of HNO3 is dissolved in 750 mL of water. What is the pH ?

HNO3(aq) m = 6.30 gM = 63.02 g/molV = 0.750 L

c = 0.133…mol/L x 1/1 = 0.133…mol/L

pH = -log[H+(aq)] = -log[0.133… mol/L] = 0.875

+ NO3-(aq)H+(aq)

n = m M = 6.30 g 63.02 g/mol = 0.0999…mol

c = n V = 0.0999…mol 0.750 L = 0.133…mol/L

just as deals with deals with

***p just means log

pH [H3O+(aq)], pOH

[OH(aq)]

at SATP…pH + pOH = 14

pOH

pH

0

7 014

7 14

3

11

9

5 9

5

3

11 113

131

to calculate the use the same formulas as pH but substitute the

pOH,[OH(aq)]

pOH = log[OH(aq)]

Try These:

1.     [OH(aq)] = 1.0 10-11 mol/L pOH =

2.     [OH(aq)] = 6.22 10-2 mol/LpOH =

3.     [OH(aq)] = 9.411 10-6 mol/LpOH =

4.     [OH(aq)] = 2 10-6 mol/LpOH =

11.00

1.206

5.0264

5.7

Summarizing pH and POHSummarizing pH and POH

pH – concentration of H+ in your solution .0 = strong acid, 7 = neutral, 14 = strong base

pOH – concentration of OH- in your solution. 14 = strong acid, 7 neutral, 0 = strong base

pH = log [H3O+

(aq)] pOH = log[OH(aq)]

pH + pOH = 14

Bases = [OH(aq)]Acids = [H3O+(aq)],

[H3O+(aq)] = 10-pH

you could also be given the pH or pOH and asked to calculate the [H3O

+(aq)] or [OH-(aq)]

[OH(aq)]= 10-pOH

Try These:

1.     pH 4.0 [H3O+(aq)] =

2.     pH 6.21 [H3O+(aq)] =

3.     pH 13.400 [H3O+(aq)] =

4.     pH 7 [H3O+(aq)] =

5.     pOH 1.0 [OH(aq)] =

6.     pOH 13.2 [OH(aq)] =

7.     pOH 6.90 [OH(aq)] =

8.     pOH 0.786 [OH(aq)] =

0.1 mol/L

6 10-14 mol/L

1.3 10-7 mol/L

0.164 mol/L

1 x 10-4 mol/L

6.2 x 10-7

mol/L

10-7 mol/L

3.98 x 10-14

mol/L

Summary of pH/pOH and concentration

-log [H3O+] = to find pH

-log [OH-] = to find OH

10-pH = to find concentration of [H3O+] 10-pOH = to find concentration of [OH-]

9. Complete the following table:

[H3O+(aq)] [OH(aq)] pH pOH Acid/Base/

Neutral

4.0 x 10-6 mol/L

10 mol/L

2.0 1011 mol/L

15.00

9.500

1.36

5.40 8.602.5 x 10-9 mol/L

4.500

15.00

-1.00

12.64

-1.00

3.30 10.705.0 x 10-4 mol/L

1.0 x 10-15 mol/L

10 mol/L1.0 x 10-15 mol/L

3.16 x 10-5 mol/L3.16 x 10-10 mol/L

2.3 x 10-13 mol/L 0.044 mol/L

acid

base

acid

acid

base

base

D. Measuring pH pH can be measured using :

1. acid-base indicators

2. pH meter

Indicators an is any

chemical that in an acidic or basic solution

acid-base indicatorchanges colour

they can bedried onto strips of paper

eg) litmus paper, pH paper

they can besolutions

eg) bromothymol blue, universal indicator, indigo carmine etc

they can be made from natural substances eg) tea, red cabbage juice, grape juice

each indicator has a where it will

specific pH rangechange colour

you can use to approximate the

two or more indicatorspH of a solution

pH Meters using a pH meter is the most

way of measuring

it has an that compares the [H3O

+(aq)] in the solution to a and it will give a of the pH

precise

electrodestandard

digital readout

pH

E. Diluting an Acid or Base

when you to an , you change the

diluting an acid will the until a pH of is reached

[H3O+(aq)] or the [OH(aq)]

add water acid or base

decrease [H3O+(aq)]

7.0

diluting a base will the until a pH of is reached

decrease [OH-(aq)]7.0

Remember: CiVi = CfVfRemember: CiVi = CfVf

A concentrated solution is made by dissolving 5g of HCl into 30 L of water. You then take 10 mL of this solution and dilute it to a volume of 50 L. What is the pH of the diluted solution?

Formulas to remember:

pH = - log [H3O+]

pOH = - log [OH-]

[H3O+] = 10-pH

[OH-] = 10-pOH

C = n/v

CiVi = CfVf

Review Assignment:Textbook p. 244 #1-28