CHEM 0010 Unit


UNIT # 8
Introduction
Objectives
Reading
8.1 Conventions and Symbols 8.2 Balancing Chemical Equations 8.3 Methods of Balancing Equations 8.4 Types of Chemical Reactions 8.5 Calculations Based on Chemical Equations
Problems 1 \| 2 \| 3 \| 4

CHEMICAL 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) 6CO₂ (g) + 8H₂O (l)

Section 9.3
Guidelines for Balancing Chemical Equations ..p219
Section 9.4
Examples Involving Balancing Equations ..p221

Back


All contents copyrighted © 1996-2006 British Columbia Institute of Technology Chemistry Department - 3700 Willingdon Avenue Burnaby, B.C. Canada V5G 3H2

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.

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.