Chapter 3 activity 2 choice of media for durability
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Chapter 3: Activity 2 Choice of Media for Durability. What do you see?. What are acids and bases?. Acids. Always contain H + (ex. HCl, H 2 SO 4 ) Acidic foods have a sour taste Neutralize bases React with most metals Turns blue litmus red Have a pH <7

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Chapter 3: Activity 2 Choice of Media for Durability

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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


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


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 Ammonia

It is a base because:

NH3 + H2O → + NH4+1(aq) OH-1(aq)


Writing Chemical Formulas for Bases

Ex: sodium hydroxide

1. Write the chemical symbol f the metal, than OH

NaOH

2. Put up the charges, and criss-cross if necessary.

+1 -1

NaOH


Writing Chemical Formulas for Bases

Ex: calcium hydroxide

1. Write the chemical symbol f the metal, than OH

CaOH

2. Put up the charges, and criss-cross if necessary.

+2 -1

Ca(OH)2


Writing Chemical Formulas for Bases

Ex: lithium hydroxide

1. Write the chemical symbol f the metal, than OH

LiOH

2. 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 elements

2. Ternary acids-H2SO4(aq)

-three different elements

-polyatomic ions (ending in ate)

-polyatomic ions (ending in ite)


Naming Binary Acids

EX: HCl(aq)

1. Use the prefix hydrofor hydrogen

2. Anion ending changes from ide to ic

3. Add the word acid at the end.

hydrochloric acid


Naming Complex Acids

Polyatomic ions ending in ite

EX: H2SO3

1. NO hydro prefix!!!

2. Anion ending changes from ITE to OUS

-Sulfite change to Sulfurous

“RITEOUS”

Add the word acid at the end

Polyatomic ions ending in ate

EX: H2SO4

1. NO hydro prefix!!!

2. Anion ending changes from ATE to IC

-Sulfate change to Sulfuric

“ICIATEit”

3. Add the word acid at the end


Naming Ternary Acids

Polyatomic ions ending in ate

EX: H2SO4

1. NO hydro prefix!!!

2. Anion ending changes from ATE toIC

-Sulfate change to Sulfuric

“ICIATEthat”

3. Add the word acid at the end

Sulfuric acid


Naming Ternary Acids

Polyatomic ions ending in ite

EX: H2SO3

1. NO hydro prefix!!!

2. Anion ending changes from ITE toOUS

-Sulfite change to Sulfurous

“RITEOUS”

  • Add the word acid at the end

    Sulfurous acid


Practice Naming Acids

1.H3PO4(aq)

-PO42-= phosphate

-Use saying “ICIATEthat”

Answer= Phosphoric acid

2. HNO2(aq)

-NO21-= nitrite

-Use saying “RITEOUS”

Answer= Nitrous acid


Writing Chemical Formulas for Acids


How to Write a Formula for an Acid:

BINARY ACIDS

Ex: hydrosulfuric acid

1. 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 charges

4. H2S(aq)


Ternary ACIDS

Ex: sulfuric acid

1. No hydro prefix so we have a polyatomic ion:

In this case “ICIATEthat”

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 charges

5. H2SO4(aq)


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