Lesson Plan: C1.5.01

Hamble Lesson Observation Plan
Learning About
Why are chemical equations always balanced?
Keywords:
  • Balanced equations: When the total number of atoms in the reactants equals the total number of atoms in the products. (1)
  • reaction (1)
  • chemical (1)
  • atoms (1)
  • Conservation of Mass: No atoms are lost or made during a chemical reaction. This means that the mass is always conserved. (1)
Memory Anchor:
Method Precise Learning Objective Linked Question / Activity
(Designed for maximum working out)
Stepping Stones Pitstop Check
(Thinking Map)
The law of conservation of mass states that no atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants. What is the law of the conservation of mass?

Model the law of conservation using molecular model kits. Teacher Demo: Lead Nitrate and potassium Iodide. Perform on balance no change in mass. Write simple word equations. Write simple symbol equations. Balance symbol equations. GF: balance complex equations and add state symbols.

This means that chemical reactions can be represented by symbol equations which are balanced in terms of the numbers of atoms of each element involved on both sides of the equation. Why must we ensure that chemical equations are balanced?

Students should understand the use of the multipliers in equations in normal script before a formula and in subscript within a formula. What do the multipliers in normal script before a chemical formula represent? Eg 2MgO

Links To the Big Ideas
ForcesParticlesEnergyCells