Unit #1Unit #2Unit #3Unit #4Unit #5Unit #6Unit #7Unit #8Unit #9Unit #10
spacerUNIT # 8  
spacerspacerIntroduction
spacerspacerObjectives
spacerspacerReading


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8.1 Conventions
spacerand Symbols
spacer8.2 Balancing
spacerChemical
spacerEquations

spacer8.3 Methods of
spacerBalancing
spacerEquations

spacerBalance by Inspection
spacerBalance algebraically
spacer8.4 Types of
spacerChemical
spacerReactions
spacer8.5 Calculations
spacerBased on
spacerChemical
spacerEquations
spacerMole-mole calculations
spacerMass-mass calculations
spacerMass-mole calculations
spacerLimiting Reagent calculations



spacerProblems
spacer1 | 2
| 3 | 4

Unit #8CHEMICAL REACTIONS

8.3 - Methods of balancing chemical equations

8.3.2 - Balance Algebraically

Take out a piece of paper and a pencil and go through this example with me. We will use algebra to solve for the coefficients. It's a 6-step process.

When propyl alcohol, CH3CH2CH2OH, burns in air, it reacts with oxygen, O2, to form carbon dioxide, CO2, and water, H2O. Write the balanced chemical reaction.

If you think you know how to do this, skip to see the balanced chemical equation.

Otherwise, let's begin:

Step 1 Identify the reactants and products.
Step 2 Write the unbalanced chemical equation.
Step 3 Assign variables as coefficients for each substance in the chemical equation.
Step 4 Determine the number of each type of atoms on each side of the arrow.

Step 5 Write out the algebraic equations and solve for the coefficients.

Step 6 Make sure that all the coefficients are whole numbers. Multiply all the coefficients by an appropriate factor to convert any fractions to whole numbers.

The balanced chemical equation is:

2 CH3CH2CH2OH (l) + 9O2 (g) reaction arrow 6CO2 (g) + 8H2O (l)



book icon
Section 9.3

spacerGuidelines for Balancing Chemical Equations ..p219

Section 9.4
spacerExamples Involving Balancing Equations ..p221

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