Chapter 3:Activity 2 Choice of Media for

Durability

What do you see?

What are acids and bases?

Acids

• Always contain H+ (ex. HCl, H2SO4)• Acidic foods have a sour taste• Neutralize bases• React with most metals• Turns blue litmus red• Have a pH <7• Turns universal indicator yellow, orange, or red

Bases

• Contain OH- (ex. NaOH, KOH)• Have a bitter taste• Feel slippery• Neutralize acids• Are corrosive• Have a pH >7• Turn red litmus blue• Turn universal indicator green, blue, or purple

Acids vs Bases

Acids vs Bases

pH• Is a measure of how much H+

is in a solution sample.• If H+= OH- then, pH=7 and the

solution is neutral.• If H+ > OH-, then pH<7 and

the solution is acidic.• If OH- >H+, then pH>7 and the

solution is basic.• The pH scale goes from 0-14,

with 7 being neutral

Universal Indicator Scale

Take a look at this!!!!!

How is pH important to artwork?

What has happened here?

How Does This Happen?

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

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

NO3(g) + H2O(l) HNO3(aq) nitric acid

Conoco Philips Plant, Linden NJ

Conoco Philips Plant, Linden NJ

What does acid rain do?CaCO3(s) + H2SO4(aq) CaSO4(aq) + H2O(l) + CO2

Marble sulfuric acid calcium sulfate water carbon dioxide

Dissolves in the water and washes

away

Zn (s) + H2SO4(aq) ZnSO4(aq) + H2(g) zinc metal sulfuric acid zinc sulfate hydrogen gas

Zinc is usually a good metal choice for outdoor stuff, but in the presence of acid rain, it reacts and washes away.

In 1992, after being displayed outdoors in an urban-industrial environment for over 60 years, Philadelphia’s version of Rodin’s The Thinker showed the effects of "acid rain" and particulate deposition common in such atmospheres. Streaking, caused by the run-off of condensate from the sculptural forms, had etched a pattern of irregular rivulets in the surface, while urban aerosols from industrial and vehicular sources built up black and other accretions. The forms were obscured; Rodin’s modeling could no longer be "read," with some high points black and recesses bright due to corrosion.

Philadelphia Museum of Art

What might be a better choice of material for outdoor art?

SiO2(s) + H2SO4(aq) no reaction Sandstone and granite sulfuric acid

Other alternatives???

The copper in this piece of artwork wouldn’t stand a chance exposed to air and water, BUT a protective coating over it can keep it looking new for ages!

How would a protective coating have affected this famous piece of

art?

Ted Talk

https://www.youtube.com/watch?v=DupXDD87oHc

Acids Both Bases

Sour taste Bitter taste

pH <7 pH >7

Blue litmus -red Red litmus-blue

Reactive w/metals Not reactive w/metals

H+ ions or H3O+ ions (hydronium)

OH- ions (hydroxide)

Conducts electricity

Corrosive

Naming Bases

A BASE is a substance that when put into water, gives away a hydroxide ion (OH-1) to another substance in the water solution.

NaOH(s) + H2O → Na+1(aq) + OH-1

(aq)

Naming Bases

1. Name the metal first and then the hydroxide ion

Ex: NaOH

Sodium hydroxide

Naming Bases

1. Name the metal first and then the hydroxide ion

Ex: KOH

Potassium hydroxide

Naming Bases

1. Name the metal first and then the hydroxide ion

Ex: Ca(OH)2

Calcium hydroxide

Naming Bases

1. A base that is commonly used is

Ex: NH3 AmmoniaIt is a base because:

NH3 + H2O → + NH4+1

(aq) OH-1(aq)

Writing Chemical Formulas for Bases

Ex: sodium hydroxide1. Write the chemical symbol f the metal, than OH NaOH2. Put up the charges, and criss-cross if necessary.

+1 -1

NaOH

Writing Chemical Formulas for Bases

Ex: calcium hydroxide1. Write the chemical symbol f the metal, than OH CaOH2. Put up the charges, and criss-cross if necessary.

+2 -1

Ca(OH)2

Writing Chemical Formulas for Bases

Ex: lithium hydroxide1. Write the chemical symbol f the metal, than OH LiOH2. Put up the charges, and criss-cross if necessary.

+1 -1

LiOH

Naming Acids

An ACID is a substance that when put into water, gives away a hydrogen ion (H+1) to another substance in the water solution.

HCl + H2O → H+1(aq)

+ Cl-1(aq)

Types of Acids

There are two types of acids:1. Binary acids-HCl(aq)

-two different elements2. Ternary acids-H2SO4(aq)

-three different elements

-polyatomic ions (ending in ate)-polyatomic ions (ending in ite)

Naming Binary AcidsEX: HCl(aq)

1. Use the prefix hydro for hydrogen2. Anion ending changes from ide to ic3. Add the word acid at the end.

hydrochloric acid

Naming Complex AcidsPolyatomic ions ending in ate

EX: H2SO4

1. NO hydro prefix!!!2. Anion ending changes from ATE to IC

-Sulfate change to Sulfuric “IC I ATE it”

3. Add the word acid at the end

Polyatomic ions ending in ite

EX: H2SO3

1. NO hydro prefix!!!2. Anion ending changes from ITE to OUS

-Sulfite change to Sulfurous “RITEOUS”3.Add the word acid at the end

Polyatomic Ion Name of Polyatomic ion

Acid formula Name of acid

Naming Ternary AcidsPolyatomic ions ending in ate

EX: H2SO4

1. NO hydro prefix!!!2. Anion ending changes from ATE to IC

-Sulfate change to Sulfuric “IC I ATE that”

3. Add the word acid at the end

Sulfuric acid

Naming Ternary AcidsPolyatomic ions ending in ite

EX: H2SO3

1. NO hydro prefix!!!2. Anion ending changes from ITE to OUS

-Sulfite change to Sulfurous “RITEOUS”3.Add the word acid at the end

Sulfurous acid

Practice Naming Acids

1. H3PO4(aq)

-PO42-

= phosphate

-Use saying “IC I ATE that”Answer= Phosphoric acid

2. HNO2(aq)

-NO21-

= nitrite

-Use saying “RITEOUS”Answer= Nitrous acid

Writing Chemical Writing Chemical Formulas for AcidsFormulas for Acids

How to Write a Formula for an Acid:BINARY ACIDSEx: hydrosulfuric acid1. Write down symbols (H and S)

2. Determine Charges (H+1 S-2)

3. Cancel charges or use criss-cross method to form subscripts to cancel out charges4. H2S(aq)

Ternary ACIDSEx: sulfuric acid1. No hydro prefix so we have a polyatomic ion: In this case “IC I ATE that”

sulfuric = sulfate (SO4)-2

Can also be “RITEOUS” sulfurous = sulfite 2. Write down symbols (H and SO4)

3. Determine Charges (H+1 SO4 -2)

4. Cancel charges or use criss-cross method to form subscripts to cancel out charges5. H2SO4(aq)