Lemonade-Ed - Lesson: Lavoisier

Lesson Plan: Lavoisier and Conservation of Mass

Navigate the knowledge tree: 🌿 Chemistry ➡ Chemical Changes ➡ Ions

Hei Mahi (Do Now)

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Are the following equations balanced or not? Yes or No - if no, write the balanced equation.

1. 2Na + 2HCl → 2NaCl + H₂

2. H₂ + O₂ → H₂O

3. C + H₂ → CH₄

Hei Mahi (Do Now) ANSWERS

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Are the following equations balanced or not? Yes or No - if no, write the balanced equation.

1. 2Na + 2HCl → 2NaCl + H₂ Yes

2. H₂ + O₂ → H₂O No, it should be 2H₂ + O₂ → 2H₂O

3. C + H₂ → CH₄ No, it should be C + 2H₂ → CH₄

Hei Mahi (Do Now)

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Count the atoms in the reactants and products of this equation, and record your answer in a table like below.

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Hei Mahi (Do Now) ANSWERS

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Count the atoms in the reactants and products of this equation, and record your answer in a table like below.

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Atoms cannot be created or destroyed. In a chemical reaction, atoms can only be rearranged from those at the start of the reaction.
Chemical equations show this by having the same number of atoms on each side of the equation. This is called balancing an equation.

Below are some simple rules for writing and balancing equations:

Small numbers after an atom's symbol tell you how many atoms are combined. For example: O₂ means two oxygen atoms combined; O₃ means three oxygen atoms combined.
Large numbers in front (called the co-efficient) mean more than one of whatever follows. For example 3O₂ means three oxygen molecules, each with the formula O₂.
You can't alter a formula to balance an equation. You can only change the numbers (co-efficient) in front.