acids and bases (muy bueno)

7/29/2019 Acids and Bases (Muy Bueno)

1/59

Acids and Bases

http://www.unit5.org/chemistry/Acids.htm
http://www.chem1.com/acad/webtext/abcon/index.html


2/59

http://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppt
http://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppthttp://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppthttp://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppthttp://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppthttp://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppthttp://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppt


3/59

Guiding Questions

What is an acid?

What makes acids dangerous?

Is acid rain an issue for us?

What does pH balanced mean?


4/59

pH scale

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

Each step on pH scale represents a factor of 10.

pH 5 vs. pH 6 (10X more acidic)pH 3 vs. pH 5 (100X different)

pH 8 vs. pH 13 (100,000X different)

: measures acidity/basicity

10x10x10x100x


5/59

pH scale

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

ACID BASE

NEUTRAL

Each step on pH scale represents a factor of 10.

pH 5 vs. pH 6 (10X more acidic)pH 3 vs. pH 5 (100X different)

pH 8 vs. pH 13 (100,000X different)

: measures acidity/basicity

10x10x10x100x

Sren Sorensen(1868 - 1939)


6/59

Acid vs. Base

Acid

pH > 7

bitter taste

does not

react with

metals

pH < 7

sour taste

react with

metals

AlikeDifferent

Related to

H+ (proton)

concentration

pH + pOH = 14

Affects pH

and

litmus paper

Base

Different

Topic Topic


7/59

Properties

electrolytes

turn litmus red

sour taste

react with metals toform H2 gas

slippery feel

turn litmus blue

bitter taste

ChemASAP

vinegar, milk, soda,

apples, citrus fruits

ammonia, lye, antacid,

baking soda

electrolytes


8/59Copyright 2007 Pearson Benjamin Cummings. All rights reserved.

Acid

Sour taste

Turns blue litmus red

Reacts with some metals to produce H2Dissolves carbonate salts, releasing CO2

Base

Bitter tasteTurns red litmus blue

Slippery to the touch


10/59

Common Acids and Bases

Strong Acids (strong electrolytes)

HCl hydrochloric acid

HNO3 nitric acid

HClO4 perchloric acidH2SO4 sulfuric acid

Weak Acids (weak electrolytes)

CH3COOH acetic acid

H2CO3 carbonic

Strong Bases (strong electrolytes)

NaOH sodium hydroxide

KOH potassium hydroxide

Ca(OH)2 calcium hydroxide

Weak Base (weak electrolyte)

NH3 ammonia

Kotz, Purcell, Chemistry & Chemical Reactivity 1991, page 145

Weak Base (weak electrolyte)

NH4OH ammonia

NH3 + H2O NH4OH


11/59

Acid + Base Salt + Water

Orange juice + milk bad taste

Evergreen shrub + concrete dead bush

Under a pine tree + fertilizer white powder

HCl + NaOH NaCl + HOHsalt water


12/59

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion

H3O+ OH-

Water

H2O

Water

H2O

Water

H2O

Water

H2O

Dorin, Demmin, Gabel, Chemistry The Study of Matter 3rd Edition, page 584


13/59

Acid-Base Neutralization

1+ 1-

+ +

Hydronium ion Hydroxide ion Water

H3O+ OH- H2O

Water

H2O

Dorin, Demmin, Gabel, Chemistry The Study of Matter 3rd Edition, page 584


14/59

Acid Precipitation

http://nadp.sws.uiuc.edu/amaps2/
http://nadp.sws.uiuc.edu/amaps2/http://nadp.sws.uiuc.edu/amaps2/


15/59

Formation of Sulfuric Acid

Kelter, Carr, Scott, Chemistry A World of Choices 1999, page 302

SO2(g) + H2O(l) H2SO3(aq)

2SO2(g) + O2(g) 2SO3(g)

SO3(g) + H2O(l) H2SO4(aq)

SO2(g) + H2O2(l) H2SO4(aq)

Catalyzed by atmospheric dust

Sulfuric acid

+

+


16/59

Figure courtesy of the National Atmospheric Deposition Program, Champaign, Ill.

The progressively darker red areas on the map indicate the lowest pH levels

and areas most prone to problems from acid rain.

Hydrogen ion concentration as pH from measurements

made at the field laboratories during 2003

National Atmospheric Deposition Program/National Trends Network

http://nadp.sws.uiuc.edu

made at the Central Analytical Laboratory, 1999


17/59

Acid Rain

Smoke stacks pollute SO2into the atmosphere. This

combines with water to form

acid rain.

Estimated sulfate ion deposition, 1999


18/59

CO2 (g) H2O (l) H2CO3 (aq)Carbondioxide CarbonicacidWater

Weakacid

Copyright 2007 Pearson Benjamin Cummings. All rights reserved.


19/59

Common Acids

Sulfuric Acid H2SO4

Nitric Acid HNO3

Phosphoric Acid H3PO4

Hydrochloric Acid HCl

Acetic Acid CH3COOH

Carbonic Acid H2CO3

Battery acid

Used to make fertilizers

and explosives

Food flavoring

Stomach acid

Vinegar

Carbonated water
http://upload.wikimedia.org/wikipedia/commons/2/24/Sulfuric-acid-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/0/08/Phosphoric-acid-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/4/48/Hydrogen-chloride-3D-vdW-labelled.pnghttp://upload.wikimedia.org/wikipedia/commons/e/ef/Acetic-acid-3D-balls.pnghttp://upload.wikimedia.org/wikipedia/commons/8/81/Carbonic-acid-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/8/81/Carbonic-acid-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/4/48/Hydrogen-chloride-3D-vdW-labelled.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/e/ef/Acetic-acid-3D-balls.pnghttp://upload.wikimedia.org/wikipedia/commons/2/24/Sulfuric-acid-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/0/08/Phosphoric-acid-3D-vdW.png


20/59

Common Acids

Formula Name of Acid Name of NegativeIon of Salt

HF hydrofluoric fluoride

HBr hydrobromic bromide

HI hydroiodic iodide

HCl hydrochloric chloride

HClO hypochlorous hypochloriteHClO2 chlorous chlorite

HClO3 chloric chlorate

HClO4 perchloric perchlorate

H2S hydrosulfuric sulfide

H2SO3 sulfurous sulfite

H2SO4 sulfuric sulfate

HNO2 nitrous nitrite

HNO3 nitric nitrate

H2CO3 carbonic carbonate

H3PO3 phosphorous phosphite

H3PO

4phosphoric phosphate


21/59


22/59

Sulfuric Acid, H2SO4Sulfuric acid is the most commonly produced industrial chemical in the world.

Uses: petroleum refining, metallurgy, manufacture of fertilizer,

many industrial processes: metals, paper, paint, dyes, detergents

Sulfuric acid is used in

automobile batteries.

H2SO4oil of vitriol
http://upload.wikimedia.org/wikipedia/commons/2/24/Sulfuric-acid-3D-vdW.png


23/59

Nitric Acid, HNO3

Nitric acid stains proteins yellow (like your skin).

Uses: make explosives, fertilizers, rubber, plastics, dyes, and pharmaceuticals.

HNO3

aqua fortis

O

OO

N

H
http://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.pnghttp://upload.wikimedia.org/wikipedia/commons/6/69/Nitric-acid-3D-balls-B.png


24/59

Hydrochloric Acid, HCl

The stomach produces HCl to aid in the digestion of food.

Uses: For pickling iron and steel.

Pickling is the immersion of metals in acid solution to remove

surface impurities.

A dilute solution of HCl is called muriatic acid (available in many hardware

stores). Muriatic acid is commonly used to adjust pH in swimming pools

and in the cleaning of masonry.

HCl(g) + H2O(l) HCl(aq)hydrogen chloride water hydrochloric acid
http://upload.wikimedia.org/wikipedia/commons/8/88/HCl_molecule_model-VdW_surface.svghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.png


25/59

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

.NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-
http://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.png


26/59

Common Bases

Sodium hydroxide NaOH lye or caustic soda

Potassium hydroxide KOH lye or caustic potash

Magnesium hydroxide Mg(OH)2 milk of magnesia

Calcium hydroxide Ca(OH) 2 slaked lime

Ammonia water NH3 H2O household ammonia

Name Formula Common Name

.NH4OH

NH41+ + OH1-

ammonium hydroxide

hydroxideion

OH1-
http://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.pnghttp://upload.wikimedia.org/wikipedia/commons/5/5a/Hydroxide-3D-vdW.png


27/59


28/59

Binary Hydrogen Compoundsof Nonmetals When Dissolved in Water

(These compounds are commonly called acids.)

The prefix hydro- is used to represent hydrogen, followed by the nameof the nonmetal with its ending replaced by the suffixicand the word

acid added.

Examples:

*HCl

HBr

*The name of this compound would be hydrogen chloride if it was NOT dissolved in water.

Hydrochloricacid

Hydrobromicacid


29/59

Naming Ternary Compounds

from Oxyacids

The following table lists the most common families of oxy acids.

one more

oxyg en atom

most

common

one less

oxygen

two less

oxygen

HClO4perchloric acid

HClO3chloric acid

HClO2

chlorous acid

HClO

hypochlorous acid

H2SO4sulfuric acid

H2SO3

sulfurous acid

H3PO4phosphoric acid

H3PO3

phosphorous acid

H3PO2hypophosphorous acid

HNO3nitric acid

HNO2

nitrous acid

(HNO)2hyponitrous acid


30/59

An acid with a

name ending in

A salt with a

name ending in

-ic

-ous

-ate

-iteforms

forms

Hill, Petrucci, General ChemistryAn Integrated Approach1999, page 60


31/59

Oxyacids Oxysalts

If you replace hydrogen with a metal, you have formed an oxysalt.A saltis a compound consisting of a metal and a non-metal. If the

salt consists of a metal, a nonmetal, and oxygen it is called an

oxysalt. NaClO4, sodium perchlorate, is an oxysalt.

HClO4perchloric acid

HClO3

chloric acid

HClO2chlorous acid

HClO

hypochlorous acid

NaClO4sodium perchlorate

NaClO3

sodium chlorate

NaClO2sodium chlorite

NaClO

sodium hypochlorite

OXYACID OXYSALT


32/59


33/59


34/59

Acid Base Systems

Type Acid Base

Arrhenius H+

or H3O+

producer

OH-

producer

Brnsted-

Lowry

Proton (H +)

donor

Proton (H +)

acceptor

Lewis Electron-pair

acceptor

Electron-pair

donor


35/59

Arrhenius Acid

1+

+ +

hydronium ion

H3O+

1-

chloride ion

Cl-

water

H2O

hydrogen chloride

HCl

(an Arrhenius acid)

Any substance that releases H+ ions as the

onlypositive ion in the aqueous solution.


36/59

Definitions

Arrhenius - In aqueous solution

HCl+ H2O H3O+ + Cl

Acidsform hydronium ions (H3O+)

H

HH H H

H

ClClO O

+

acid Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


37/59


38/59

Brnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton.

Base = any substance that accepts a proton.


39/59

Brnsted-Lowry Acids and Bases

1+

+

hydronium ion

H3O+

1-

chloride ion

Cl-

(base)

H2O

(acid)

HCl

d+ d-

Acid = any substance that donates a proton.

Base = any substance that accepts a proton.


40/59


41/59

Definitions

F -

H2PO4-

H2O

HF

H3PO4

H3O+

Give the conjugate base for each of the following:

Polyprotic - an acid with more than one H+

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


42/59

Neutralization

Neutralization is a chemical reaction between an acid and a base

to produce a salt (an ionic compound) and water.

NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

base acid salt water

Some neutralization reactions:

H2SO4(aq) + NaOH(aq) Na2SO4 + HOH

sulfuric acid sodium hydroxide sodium sulfate water

HC2H3O2(aq) + Ca(OH)2(aq) Ca(C2H3O2)2 + HOH

acetic acid calcium hydroxide calcium acetate water

2 2

2 2


43/59

ACID + BASE SALT + WATER

HCl + NaOH NaCl + H2O

HC2H3O2 + NaOH NaC2H3O2 + H2O

Salts can be neutral, acidic, or basic.

Neutralization does not mean pH = 7.

weak

strong strong

strong

neutral

basic

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


44/59


45/59


46/59


47/59


48/59

pH = - log [H+]

pH = 4.6

pH = - log [H+]

4.6 = - log [H+]

- 4.6 = log [H+]

- 4.6 = log [H+]

Given:

2nd log

10x

antilog

multiply both sides by -1

substitute pH value in equation

take antilog of both sides

determine the [hydronium ion]

choose proper equation

[H+] = 2.51x10-5M

You can check your answer by working backwards.

pH = - log [H+]

pH = - log [2.51x10-5M]

pH = 4.6

Recall, [H+] = [H3O+]


49/59

Acid Dissociation

monoprotic

diprotic

polyprotic

HA(aq) H1+(aq) + A1-(aq)

0.03 M 0.03 M 0.03 M

pH = - log [H+]

pH = - log [0.03M]

pH = 1.52

e.g. HCl, HNO3

H2A(aq) 2 H1+(aq) + A2-(aq)

0.3 M 0.6 M 0.3 M

pH = - log [H+]

pH = - log [0.6M]

pH = 0.22

e.g. H2SO4

Given: pH = 2.1find [H3PO4]

assume 100%

dissociation

e.g. H3PO4H3PO4(aq) 3 H

1+

(aq) + PO43-

(aq)? M x M

pH = ?


50/59

Given: pH = 2.1

find [H3PO4]

assume 100%dissociation

H3PO4(aq) 3 H1+(aq) + PO4

3-(aq)

XM 0.00794 M

Step 1) Write the dissociation of phosphoric acid

Step 2) Calculate the [H+] concentration pH = - log [H+]

2.1 = - log [H+]

- 2.1 = log [H+]

2nd log - 2.1 = log [H+]2nd log

[H+] = 10-pH

[H+] = 10-2.1

[H+] = 0.00794 M

[H+] = 7.94 x10-3M7.94 x10-3M

Step 3) Calculate [H3PO4] concentration

Note: coefficients (1:3) for (H3PO4 : H+)

7.94 x10-3M3

= 0.00265 MH3PO4


51/59


52/59

pH Indicators


53/59

pH Paper

pH 0 1 2 3 4 5 6

pH 7 8 9 10 11 12 13


54/59

Indicator Colors in Titration
http://images.google.com/imgres?imgurl=http://www.funsci.com/fun3_en/acids/acids_01.jpg&imgrefurl=http://www.funsci.com/fun3_en/acids/acids.htm&h=294&w=304&sz=17&hl=en&start=1&tbnid=PW71Yfkt-yvLCM:&tbnh=112&tbnw=116&prev=/images?q=acids&gbv=2&hl%


55/59

Red Cabbage IndicatorCopyright 2007 Pearson Benjamin Cummings. All rights reserved.
http://images.google.com/imgres?imgurl=http://www.funsci.com/fun3_en/acids/acids_01.jpg&imgrefurl=http://www.funsci.com/fun3_en/acids/acids.htm&h=294&w=304&sz=17&hl=en&start=1&tbnid=PW71Yfkt-yvLCM:&tbnh=112&tbnw=116&prev=/images?q=acids&gbv=2&hl%


56/59


57/59

23

24

How to read a buret volume

23.45 mL

(not 24.55 mL)

24.55 mL?


58/59

Titration

Titration

Analytical method in which

a standard solution is

used to determine theconcentration of an

unknown solution.

standard solution

unknown solutionCourtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


59/59

Equivalence point (endpoint)

Point at which equal amounts of

H3O+ and OH- have been added.

Determined by

indicator color change

Titration

dramatic change in pH

acids and bases (muy bueno)

Documents