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

Universal Indicator Scale 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 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

How would a protective coating have affected this famous piece of art? 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

H+ ions or H3O+ ions (hydronium) 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

NaOH(s) + H2O → Na+1(aq) + OH-1(aq) 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)

Ex: NaOH Sodium hydroxide Naming Bases 1. Name the metal first and then the hydroxide ion Ex: NaOH Sodium hydroxide

Ex: KOH Potassium hydroxide Naming Bases 1. Name the metal first and then the hydroxide ion Ex: KOH Potassium hydroxide

Ex: Ca(OH)2 Calcium hydroxide Naming Bases 1. Name the metal first and then the hydroxide ion Ex: Ca(OH)2 Calcium hydroxide

Ex: NH3 Ammonia It is a base because: NH3 + H2O → + NH4+1(aq) OH-1(aq) 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 hydrochloric acid EX: HCl(aq) 1. Use the prefix hydro for hydrogen 2. Anion ending changes from ide to ic 3. Add the word acid at the end. hydrochloric acid

Polyatomic ions ending in ate Polyatomic ions ending in ite Naming Complex Acids Polyatomic 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” Add the word acid at the end Polyatomic Ion Name of Polyatomic ion Acid formula Name of acid

Polyatomic ions ending in ate Naming Ternary Acids Polyatomic 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

Polyatomic ions ending in ite Naming Ternary 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 Sulfurous acid

Practice Naming Acids 1. H3PO4(aq) Answer= Phosphoric acid 2. HNO2(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 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 “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 charges 5. H2SO4(aq)