Unit 2.4: pH, Oxidation,
Reduction, and Catalysts
Bell Work Nov 4
• Agenda:
1.Planner:
1. Late Work Due Nov 5
2. Unit 2 Test Tues Nov 11
3. Study Guide Due Tues Nov 11
2.Bell Work
3.Good Things
4.Notes
5.Indicator Demo
6.Finish Elements Video
• Bell Work:
• What are 2 thing you learned
from the video yesterday?
Hunting the Elements
Hunting the Elements- Video
Characteristics of Acids
• Acid: A substance that tastes sour and reacts with metals
and carbonates (CO3)
• Examples:
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Hydrochloric Acid- HCl
Nitric Acid
Sulfuric Acid
Citric Acid
Acetic Acid (Vinegar)
Citrus Fruits (oranges, lemons, limes)
Acids: Reactions with Metals and Carbonates
• Acids react with certain metals to produce hydrogen gas (H2)
• Acids are corrosive, meaning they “eat away” at materials
• Example:
• Mg + 2HCl -> H2 + MgCl2
• Acids react with carbonates
• Vinegar and baking soda = acetic acid and sodium bicarbonate
Characteristics of Bases
• Base: a substance that tastes bitter and feels slippery
• When something is basic, it is often called “alkaline”
• Examples:
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Sodium hydroxide (NaOH)
Ammonia
Soap
Detergent
Baking Soda
Most household cleaners
Indicators
• Indicators are substances that turn color based on how acidic or how
basic something is
• Indicator Demo
[H+] and [OH-]
• In water, acids produce Hydrogen ions [H+] and an anion
• Therefore, an acid is any substance that produces H+ in water
Example:
HCl  H+ +Cl- (in water)
• In water, bases produce hydroxide ions [OH-] and a cation
• Therefore, a base is any substance that produces [OH-] in water
Example:
NaOH  Na+ + OH- (in water)
pH Scale
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The strength of acids and bases depends on the concentration of [H+]
pH scale is numbered 0-14
7 is neutral
Low pH 0-6 tells you the concentration of H+ is high (acidic)
High pH 8-14 tells you the concentration of H+ is low (basic)
Use litmus paper to test pH
• Match color of paper to key
Acid-Base Reaction (aka: neutralization
reaction)
• Called a “neutralization reaction” because an acid and a base
added together with neutralize the pH and get to 7
• Reaction
• Acid + Base  Water + Salt (ionic compound)
• Example:
• HCl + NaOH  H2O + NaCl
Bell Work Nov 5
• Agenda:
1.Turn in all Late work
2.Planner:
1. Unit 2 Test Tues Nov 11
2. Study Guide Due Tues Nov 11
3. pH Lab Due Thurs
3.Bell Work
4.Good Things
5.pH Lab
• Bell Work:
Bell Work Nov 6
• Agenda:
1.Turn in pH Lab
2.Planner:
1. Unit 2 Test Tues Nov 11
2. Study Guide Due Tues Nov 11
3. Catalyst Lab Due Monday
3.Bell Work
4.Good Things
5.Catalyst Lab
• Bell Work:
Catalyst
• A substance that speeds up a reaction but isn’t a reactant
• Biological catalysts are called enzymes
• Examples:
• Elephant Toothpaste and Genie in a Bottle used Potassium
Iodide to speed up the decomposition reaction of hydrogen
peroxide
• Lactase helps to break down Lactose in milk
Bell Work Nov 7
• Agenda:
1.Planner:
1. Unit 2 Test Tues Nov 11
2. Study Guide Due Tues Nov 11
3. Catalyst Lab Due Monday
2.Bell Work
3.Good Things
4.Notes
• Bell Work:
Oxidation and Reduction Reactions
• Oxidation: A chemical reaction commonly involving oxygen
• An atom accepts electrons while combining with other
elements. The atom giving away or losing electrons is said to
be oxidized
• Exothermic
• Examples:
burning of paper, rusting of ion
• Reduction:
• The opposite of oxidation
• The atom gaining reaction is said to be reduced
• Endothermic
• OIL RIG: Oxidation is losing, Reduction is gaining
Oxidation and Reduction Examples
• Batteries
• Rising of dough with yeast depends on oxidation of sugars to CO2 and H2O. The CO2
gives the rise.
• Tarnishing of silverware, 4Ag + 2H2S + O2  2Ag2S(black) + 2H2O
• Reduction of hypochlorite or perborate in bleach during oxidation of stains on
clothes.
• Reduction of hydrogen peroxide to water on bleaching of hair blonde.
• Reduction of chlorine to chloride during oxidative destruction of pathogens in
swimming pools or drinking water.