Acid bases and salts
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Acid, Bases, and Salts. Chemistry—Part 1. I. Acids. H   is a nonmetal or polyatomic ion  could be Cl - , SO 4 2- , etc. Ex: HCl, HF, H 2 SO 4 , HClO 4 , H 3 PO 4. Acids (con’t). dissociate to form H + ions (protons) Hydrogen Atom Hydrogen Ion (proton). e -. +.

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Acid, Bases, and Salts

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Acid bases and salts

Acid, Bases, and Salts

Chemistry—Part 1


I acids

I. Acids

H

 is a nonmetal or polyatomic ion

 could be Cl- , SO42-, etc.

Ex:HCl, HF, H2SO4 , HClO4, H3PO4


Acids con t

Acids (con’t)

dissociate to form H+ ions (protons)

Hydrogen AtomHydrogen Ion(proton)

e-

+


A ionization in water

A. Ionization in Water

H3O+ + Cl-

HCl + H2O 

H+ combines with H2O to form H3O+

Hydronium Ion

H+(proton) is attracted to lone e- pairs in H2O

+

-


Try this

Try This:

H2SO4 + H2O 

H3PO4 + H2O 

2

2 H3O+ + SO42-

+

SO42-

SO42-

+

3

3 H3O+ + PO43-


B examples

B. Examples

  • Soda pop – H2CO3, H3PO4

  • Vinegar (acetic acid) – HC2H3O2

  • Lemons – citric acid

  • Stomach acid – HCl

  • Battery acid – H2SO4

  • Sour Patch Kids – Tartaric Acid


C properties

C. Properties

  • taste sour

  • conduct electricity

  • turn litmus red

  • react with some metals to produce H2 (g) Remember, Zn + 2HCl  ZnCl2 + H2(g)

  • corrosive

  • All form H+ ions in solution


Ii bases

II. Bases

contain OH- (hydroxide ions)

Ex: Ca(OH)2, LiOH, NH4OH, NaOH

Also calledalkaline (alkali)

Alkali Flats

Bonneville Salt Flats, Utah


A ionization in water1

A. Ionization In Water

H2O

NaOH Na+ + OH-

NH4OH

Ca(OH)2

H2O

NH4+ + OH-

H2O

Ca2+ + 2 OH-


B examples1

B. Examples

  • Drano – NaOH

  • Oven cleaner – KOH

  • Tums – Ca(OH)2

  • Glass cleaner – NH4OH


C properties1

C. Properties

  • Taste bitter (Baking Soda)

  • Conduct electricity

  • Turn litmus blue

  • Feel slippery (hard to wash off of skin)

  • Caustic (dissolves protein, ie. YOU)

  • Form OH- ions


Iii reactions of acids and bases

III. Reactions of Acids and Bases

Neutralization:

Acid + Base  Salt + Water

HBr + NaOH 

Type of reaction?

NaBr + H2O

DOUBLE DISPLACEMENT!


Try this1

Try This:

HF+LiOH 

H2SO4 +KOH

HOH + LiF

(H2O)

H2O + K2SO4

2

2


Antacids

Antacids

Neutralize stomach acid

Ex: Tums

HCl + Ca(OH)2 

Milk of Magnesia (demo)

HCl+Mg(OH)2 

2

H2O + CaCl2

2

H2O + MgCl2

2

2


Iv electrolyte solutions

IV. Electrolyte Solutions

Substances whose water solutions conduct electricity

NaCl (c) vs. NaCl (aq)

Sucrose (c) vs. Sucrose (aq)

H2O (distilled) vs. H2O (tap)

There must be ions present to conduct


Strong weak electrolytes

Strong & Weak Electrolytes

NaCl (s)

HF (s)

HF

F+

Na+

Cl-

HF

HF

Na+

H+

Cl-

Na+ + Cl-

only ions are present

H+ + F-

mostly HF present;

only some ions

STRONG ELECTROLYTES

Ionize 100%

NaCl 

WEAK ELECTROLYTES

Only partially ionize

HF 


Conductivity demo

Conductivity Demo

NH4OH + HC2H3O2

H2O + NH4C2H3O2

Weak

Base

Weak

Acid

Salt


Practice

Practice

H?

?OH

HBr

LiOH

H2CO3

KOH

H2SO4

NH4OH


Lab 49 pre lab

Lab 49 Pre - Lab

NaCl 

FeCl3 

C6H12O6 

Na+ (aq) + Cl- (aq)

Fe3+ (aq) + 3 Cl- (aq)

C6H12O6 (aq)


V naming acids bases salts

V. Naming Acids, Bases & Salts

Acid Names

1. Binary Acids

contain only TWO elements

ex: HClHydrochloric Acid

Hydro-stem-ic Acid

Try: HBr

HF

H2S

Hydrobromic Acid

Hydrofluoric Acid

Hydrosulfuric Acid


Acid bases and salts

  • Ternary Acids

    contain THREE elements (usually)

    contain H and a polyatomic ion

    ate icite  ous

    ex:H2CO3carbonate carbonic

    Carbonic Acid


Try these

Try These

HNO2

nitrite nitrous

Nitrous Acid

HNO3

nitrate nitric

Nitric Acid

H2SO3

sulfite sulfurous

Sulfurous Acid

H2SO4

sulfate sulfuric

Sulfuric Acid


Base names iupac nomenclature

Base Names (IUPAC Nomenclature)

Combine names of ions

NaOH

Sodium Hydroxide

Ca(OH)2

Calcium Hydroxide


Salt names

Salt Names

Combine names of ions

NaBr

Sodium Bromide

K2SO4

Potassium Sulfate

Cu(NO3)2

Copper (II) Nitrate


Vi salts

VI. Salts

Salts are ionic and crystalline


A dissociation in water

A. Dissociation in Water

SaltCation + Anion

LiCl

Na2SO4

H2O

H2O

Li++Cl-

H2O

2 Na+ + SO42-


B cation and anion

B. Cation and Anion

Cation: Positive (+) charge

The ___________ contributes the cation

(acid/base?)

Anion: Negative (-) charge

The ___________ contributes the anion

(acid/base?)


C examples

C. Examples

Na+

Cl-

Na+

HCO3-

K+

SO42-


Parent acid parent base

Parent Acid / Parent Base

Parent Acid: The acid that contributes the ANION to the salt

Parent Base: The base that contributes the CATION to the salt


Viii strong acids and bases

VIII. Strong Acids and Bases

STRONG ACIDS—DISSOCIATE 100 %

HClHNO3H2SO4

STRONG BASES—DISSOCIATE 100%

All Alkali Metals (IA) form strong bases


Viii weak acids and bases

VIII. Weak Acids and Bases

WEAK ACIDS—DO NOT DISSOCIATE 100 %

WEAK BASES—DO NOT DISSOCIATE 100%

How would a weak acid conduct electricity compared to a strong acid?


Ix polyprotic acids

IX. Polyprotic Acids

Acids with more than one proton (H+)

  • Examples

    H2SO4H3AsO4H3PO4H2CO3H2S


B step by step ionization

B. Step – By – Step Ionization

Acids lose one proton at a time

1st H3PO4

2ndH2PO4- 

3rdHPO4-2 

H3PO4  3H+ + PO43-

H+ +

H2PO4-

H+ +

HPO4-2

H+ +

PO4-3

H3PO4 + H2O 

3

3 H3O+ + PO43-


Questions

Questions

1. Which of the following are polyprotic acids?

a) HCld) HC2H3O2

b) NH3e) H3PO4

c) H2SO4f) HNO3

2. Which acid is harder to ionize: H3PO4 or HPO4-2? Why?

The -2 charge attracts protons (H+)

3. Which acid is stronger: H2SO4 or HSO4-? Why?

easier to lose protons (H+)


Lab 50 answers

Lab 50 Answers


Water as an acid and a base

Water as an acid and a base

amphoteric:

water behaves as an acid & base

H2O + H2OH3O+ + OH-

acidbaseconjconj

acidbase


X anhydrides

X. Anhydrides

Without water

Acidic Anhydrides—

non-metallic oxides that combine with H2O to form an acid

SO2 + H2O  H2SO3

CO2 + H2O 

H2CO3

Acid Anhydrides


Acid bases and salts

Basic Anhydrides—

metal oxides that combine with H2O to form a base

CaO + H2O  Ca(OH)2

Na2O + H2O 

2 NaOH

Basic Anhydrides


Try these acidic or basic anhydride

Try These: Acidic or Basic Anhydride?

K2O

Basic Anhydride

NO2

Acidic Anhydride


Acid bases and salts

  • http://www.epa.gov/maia/images/acid.jpg


Acid bases and salts1

Acid, Bases, and Salts

Chemistry—Part 2


I molarity

I. Molarity

Example: 6 KOH0.1 H2SO42 NaCl

A measure of concentration

M

M

M


Concentration

Concentration

6 M

1 M


Examples

Examples

3 M HNO3 =

20 moles in 5 L = ? M


Try this2

Try This!

If 80 grams of NaOH (MW=40) is dissolved in 2 L, find the molarity.

6 moles of HBr in 250 ml. Molarity?


Now try this one

Now Try This One!

How many moles of HCl are in 500 ml of a 3 M solution?


Ii titration

II. Titration

Using a solution of to determine the concentration of another solution.

A neutralization reaction

Acid + Base 

known concentration

Salt + Water


End point

End Point

The point at which neutralization is complete

moles H+ = moles OH-

use (like phenolphthalein) to determine the end point

acid-base indicators


Acid bases and salts

Acidic—before neutralization

Neutral—

”End Point”

Basic—

“overshot endpoint”


Acid bases and salts

NaOH 

HCl 

H2SO4

Na+ + OH-

50 ml

1 M

1 M

H+ + Cl-

50 ml

1 M

1 M

2 H+ + SO42-

25 ml

1 M

2 M


Acid bases and salts

NaOH  Na+ + OH-

HCl  H+ + Cl-

50 ml

1 M

1 M

25 ml

2 M

2 M


Titration equation

Titration Equation

MA = Molarity of Acid

VA = Volume of Acid

#H+= Number of H’s in acid formula

UNITS MUST MATCH!!!

MB = Molarity of Base

VB = Volume of Base

#OH- = Number of OH’s in base formula


Try this3

Try This

50 ml of 0.1 M NaOH is neutralized by 5 ml of HCl. Find the molarity of the acid.

(5ml)(1H+)

(5ml)(1H+)


Try this4

Try This

40 ml of 1M KOH is neutralized by 10 ml of sulfuric acid. Find the molarity of acid.

(10ml)(2H+)

(10ml)(2H+)


Iii indicators

III. Indicators

Weak organic acids or bases that are a different color in an acid than in a base

Ex:

Phenolpthalein

Bromothymol Blue

Litmus

Red Cabbage


Limitations of indicators

Limitations of Indicators

Solutions must be colorless

Eye must be able to detect the change


Iv ionization of water

IV. Ionization of Water

[ ] stands for

concentration

In pure water, [H+] = 10-7 M and [OH-] = 10-7 M

1 water out of 10,000,000 forms ions


K w water s ionization constant

Kw – water’s ionization constant

Kw = [H+] [OH-]

Kw = (10-7) (10-7)

Kw = 10-14

so…

10-14 = [H+][OH-]

CONSTANT

Add Acid?

Add Base?


Example 1

Example #1

[OH-] = 10-6 M[H+] = ?


Example 2

Example #2

[H+] = 10-3 M[OH-] = ?


Ph scale

pH Scale

Used to measure acidity

Based on the concentration of H+ ions


Acid bases and salts

When

the [H+] increases by 10,

the pH decreases by 1.

When

the pH increases by 2,

the [H+] decreases by _____

102 = 100


Ph log h

pH = -log[H+]

4

[H+] = 10-4pH = ______acidic or basic?

[H+] = 10-11pH = ______acidic or basic?

11


Poh log oh

pOH = -log[OH+]

3

[OH-] = 10-3pOH = ______

[H+] = 10-9pOH = ______

5


Ph poh 14

pH + pOH = 14

Why?

[H+] [OH-] = 10-14

(10-7) (10-7) = 10-14

pH + pOH = 14

- log

- log


Try these1

Try These:

For a solution that is 0.1 M HCl…

  • What is the pH?

  • What is the concentration of OH- ions?

  • What is the pOH?

    For a solution that is 0.001 M NaOH…

  • What is the pOH?

  • What is the pH?

  • What is [H+]?

    For a solution that has a pH of 8…

  • What is the [H+]?


Hydrolysis

Hydrolysis

The reaction of a salt with water to form an acidic or basic solution

Recall Strong Acids:

Recall Strong Bases:

HClHNO3H2SO4

Group IA Hydroxides


Look at the parent acid parent base

Look at the Parent Acid & Parent Base


Ex naf

Ex: NaF

Parent Acid:

Parent Base:

So…NaF is BASIC

HF

strong or weak?

NaOH

strong or weak?


Try this fe no 3 3

Try This: Fe(NO3)3

Parent Acid:

Parent Base:

So…Fe(NO3)3 is ACIDIC

HNO3

strong or weak?

Fe(OH)3

strong or weak?


Try this nacl

Try This: NaCl

Parent Acid:

Parent Base:

So…NaCl is NEUTRAL

HCl

strong or weak?

NaOH

strong or weak?


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