1. Topic 3: How do you spell relief?
Unit 3 – Environmental Chemistry

2. Sec. 6.1 Properties of Acids and Bases
Acids and Bases can be defined by their properties (operational definition)
Bases
Red litmus to blue
pH > 7
High conductivity
Taste bitter
Neutralize acids
Feels slippery
Ionic compounds
Acids
Blue litmus to red
pH < 7
High conductivity
Taste sour
Neutralize bases
Reactive with active metals
eg. Zn or Mg to form H2 (g)

3. The pH scale

4. Acid – Base Indicators Indicators
Substances that change color when the acidity changes
Synthetic dyes, plant compounds
When changing from its acid form to its basic form it will be a blend of its 2 colors.
Eg. Litmus at pH < 6 is red
pH > 8 is blue
pH 6-8 is purple

5. Using Indicators pH test strips
These are papers with a combo of indicators to give a color range that matches a pH range.

6. pH meters
Digital pH meters can give an accurate pH.

7. Neutralization Reaction
The reaction between an acid and a base
Acid + Base  Salt + Water
We often want to control acid effects:
Acid precipitation causes buildings/statues to corrode
It is caused by pollution reacting with water in the air.
Soil conditions change and plants can’t grow properly
Fish die in polluted waters

9. A neutralization reaction that uses lime (calcium carbonate – CaCO3)
It’s released by aircraft into a lake where it reacts with acid and the acid gets neutralized.
Liming

10. Controlling Emissions
Emissions are the pollutants from smokestacks and vehicle exhaust.
For vehicle exhaust cars are equipped with Catalytic Converters.
They help hydrocarbons combust better and release less pollution.
Controlling Emissions

11. Catalytic Converter

12. Scrubber