Topic 3 Acids and Bases

The pH Scale:

Properties of Acids and Bases:

Acids:-have a pH less than 7- Taste sour- Cause chemical burns

and can corrode metals- Contain H+ ions and a

negative ion there for they are consided IONIC

- Examples: HCl, HF, H2SO4,

Bases:- Have a pH more than 7- Taste Bitter- Contain OH- ions

(hydroxide) with a metal in front

Examples: NaOH, Ca(OH)2

Acid Base Indicators:

1. Red Litmus Paper:Stys red in an acid turns blue in a base2. Blue Litmus PaperStays blue in a base and turns red in an acid3. pH paper tells the exact pH4. Bromothymol Blue:Turns yellow in an acid5. Phenothelien:Turns Pink in a base

Acid Precipitation

Types:

1. SO2(g) + H20(l) H2S03(aq) – sulfurous acid

2. SO3(g) + H20(l) H2S04(aq) – surfuric acid

3. N02(g) + H20(l) HN02(aq) + HN03(aq) – nitrous and nitric acid

4. CO2(g) + H2O(l) H2CO3(aq) – carbonic acid

Effects of Acid Precipitation

CO2 Emissions

• http://www.youtube.com/watch?v=kqV-kx2ClXU

• http://www.youtube.com/watch?v=HE6Y0iEuXMQ

Using Chemistry to Control Acid Rain

• Liming – acid/base neutralixation• Catalytic Converters• Scrubbers

Liming

• Neutralizes the rain AFTER it has fallenRxn: CaCO3(s) + H2SO4(aq) CaSO4(s) + H2O(l) +

CO2(g)

Catalytic Converters

• Removes oxides from the factories and cars BEFORE they get into the air

Scrubbers

• A device installed in large factories that use a sorbent that absorbs the harmful oxides