Topic 3: How do you spell relief?
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Transcript of Topic 3: How do you spell relief?
Topic 3: How do you spell relief? Unit 3 – Environmental Chemistry
Sec. 6.1 Properties of Acids and Bases
• Acids• Blue litmus to red• pH < 7• High conductivity• Taste sour• Neutralize bases• Reactive with active
metalseg. 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)
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
Using Indicators
• pH test strips• These are papers with a combo of indicators to give a color
range that matches a pH range.
pH meters• Digital pH
meters can give an accurate pH.
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
Liming
• 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.
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.
Catalytic Converter
Scrubber