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

8.3.1 - Balance by Inspection

Take out a piece of paper and a pencil and go through this example with me. We will balance this chemical equation by inspection. 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 Count the number of each type of atoms on both sides of the arrow.
Step 4 Decide the order of atom(s) to be balanced.

  • start with the compound that is made up of the most different kinds of elements.

  • pick the element(s) within the compound that appear only in one substance on each side of the arrow and balance it (them).

  • pick the element(s) within the compound that appear more than once on each side of the arrow and balance it (them).

  • Balance uncombined elements last.
  • summary
    Step 5 Balance each type of atoms.

    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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