Topic 3: How do you spell relief?

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

2. 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) • Bases • Red litmus to blue • pH > 7 • High conductivity • Taste bitter • Neutralize acids • Feels slippery • Ionic compounds • Acids and Bases can be defined by their properties (operational definition) Sec. 6.1 Properties of Acids and Bases

3. The pH scale

4. 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 Acid – Base Indicators

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

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

7. 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 Neutralization Reaction

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. 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