Learning Objective

In this lesson we will revise how to balance a chemical equation to reflect the conservation of mass during a chemical reaction.

Learning Outcomes

By the end of this lesson you will be able to:

  • Write word equations and formula equations to represent chemical reactions.
  • Include states of matter in formula equations.
  • Balance formula equations to reflect conservation of mass.

lesson contents balancing chemical equations

Lesson Topics

1 | Describing Chemical Reactions With Equations

2 | Conservation of Mass

3 | Steps for Balancing a Chemical Equation

4 | Tips for Balancing Chemical Equations


Lesson Summary

  • A word equation shows the chemical names of all reactants and products involved in a chemical reaction.
  • A formula equation shows the chemical formulas of reactants and products.
  • Formula equations may also include the states of matter of reactants and products, in brackets after each chemical formula.
  • (s) represents solids.
  • (l) represents liquids.
  • (g) represents gases.
  • (aq) represents aqueous solutions.
  • A balanced equation shows the ratios of reactants and products.
  • A balanced equation reflects the Law of Conservation of Mass and shows that atoms are neither created nor destroyed during a chemical reaction, but only rearranged.
  • Steps for balancing a chemical equation:
  • Write the formula equation showing all reactants and products.
  • Tally up the total numbers of each type of atom for both sides of the equation.
  • Place coefficients in front of reactants and products until there are equal numbers of each type of atom on both sides of the equation.

balanced equation particle diagram

(Header image: JSquish, Wikimedia Commons)


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