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Chemistry 20.1. 20.1. What Are Oxidation and Reduction?. The substance gaining oxygen is oxidized, while the substance losing oxygen is reduced. These reactions are called oxidation-reduction reactions and are also known as redox reactions. 20.1. What Are Oxidation and Reduction?.
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20.1 What Are Oxidation and Reduction? • The substance gaining oxygen is oxidized, while the substance losing oxygen is reduced. • These reactions are called oxidation-reduction reactions and are also known as redoxreactions.
20.1 What Are Oxidation and Reduction? • Electron Shift in Redox Reactions • How is the gain or loss of electrons linked to oxidation and reduction?
20.1 What Are Oxidation and Reduction? • Losing electrons is oxidation. Gaining electrons is reduction. • Oxidation is now defined to mean complete or partial loss of electrons or gain of oxygen. • Reduction is now defined to mean complete or partial gain of electrons or loss of oxygen.
https://www.youtube.com/watch?v=lQ6FBA1HM3s • Crash Course: Why are they called Redox??
20.1 What Are Oxidation and Reduction?
20.1 What Are Oxidation and Reduction? • The substance that loses electrons is called the reducing agent. The substance that accepts electrons is called the oxidizing agent.
https://www.youtube.com/watch?v=5rtJdjas-mY • Tyler Dewitt: Intro to redox
for Conceptual Problem 20.1 Problem Solving 20.1 Solve Problem 1 with the help of an interactive guided tutorial.
20.1 What Are Oxidation and Reduction? • Redox With Covalent Compounds
20.1 What Are Oxidation and Reduction?
20.1 Corrosion • Iron, a common construction metal often used in the form of the alloy steel, corrodes by being oxidized to ions of iron by oxygen.
20.1 Corrosion • Resistance to Corrosion • Aluminum resists corrosion because it forms a protective coating of aluminum oxide.
20.1 Corrosion • Controlling Corrosion • Painting a surface protects it from corrosion. Chromium metal also serves as a protective coating.
20.1 Corrosion • Zinc blocks attached to the steel hull of this ship oxidize instead of the iron, preventing corrosion.
20.2 Assigning Oxidation Numbers • An oxidation number is a positive or negative number assigned to an atom to indicate its degree of oxidation or reduction.
20.2 Assigning Oxidation Numbers
https://www.youtube.com/watch?v=-a2ckxhfDjQ • Tyler Dewitt: Assigning Oxidation Numbers
https://www.youtube.com/watch?v=zpCy7KwqDO8 • Practice Problems • Worksheet
20.1 Section Quiz. • 20.1.
20.1 Section Quiz. • 1. Choose the correct words for the spaces. During oxidation, an element _______ electrons. During reduction, an element ________ electrons. • gains, loses • loses, gains • gains, donates • gains, accepts
20.1 Section Quiz. • 2. Choose the correct words for the spaces. During reduction, a substance may _______ oxygen or ________ hydrogen. • gain, lose • lose, gain • gain, gain • lose, lose
20.1 Section Quiz.. • 3. The element that donates electrons in a redox reaction is called the reducing agent. This means the reducing agent is always • the more active element. • the less active element. • oxidized. • reduced.
20.1 Section Quiz. • 4. Which substance is the reducing agent in the following chemical reaction? • Fe2O3 + 3CO 2Fe + 3CO2 • Fe2O3 • CO • Fe • CO2
20.1 Section Quiz. • 5. The following equations describe the corrosion of iron to iron hydroxides in moist conditions. • 2Fe(s) + O2(g) + 2H2O(l) 2Fe(OH)2(s) • 4Fe(OH)2(s) + O2(g) + 2H2O(l) 4Fe(OH)3(s) • What substances in the equations are being oxidized? • Fe(s) and Fe(OH)2(s) • the O2(g) in both reactions • the O2(g) and H2O(l) in both reactions • Fe(OH)2(s) and Fe(OH)3(s)