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Ch.4 - Chemical Quantities & Aqueous ReactionsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch.17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds
Solubility Rules
Molecular Equations
Gas Evolution Equations
Solution Stoichiometry
Complete Ionic Equations
Calculate Oxidation Numbers
Redox Reactions
Balancing Redox Reactions: Acidic Solutions
Balancing Redox Reactions: Basic Solutions
Activity Series
Additional Guides
Oxidation Reduction (Redox) Reactions (IGNORE)
Oxidation Number (IGNORE)
Net Ionic Equation (IGNORE)

Calculating Oxidation Numbers is the first pivotal step in understanding redox reactions. 

Calculate Oxidation Numbers

Concept #1: Oxidation Number

Elements in Natural State have an oxidation number of zero: H2, N2, O2, F2, P4, S8, Cl2, Se8, Br2.

Example #1: Which of the following compounds would have an oxidation number or oxidation state equal to zero?

Concept #2: Ions

Oxidation number of monoatomic ions equals to their charge.

Example #2: Which of the following elements would have the most positive oxidation number based on its ionic form?

Practice: Which of the following elements would have the lowest oxidation number?

Concept #3: Oxidation Number Rules

Specific rules exist for calculating oxidation numbers of group 1A and 2A elements, F, H, O and Halogens.

Example #3: Which compound has oxygen with the lowest oxidation state?

Concept #4: Oxidation Number of Non-listed Elements

Example #4: Give the oxidation number of the carbon atom in the acetate ion: C2H3O2