1. Balancing equations Unit 2 Chemistry

2. Writing Chemical Equations Products: are the chemicals that are made or produced in the reaction. Reactants: are the chemicals that begin or go into the reaction before it takes place. Chemical reaction: when the chemicals that go into the reaction (reactants) change and new chemicals (products) are formed.

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4. Symbols in an equation “+” tells us that 2 compounds are combining. Key words that tell us this are: combines, reacts, and, etc. acts like an equal sign to separate the reactants and products. Key words: to form, to produce, to make, synthesizes, decomposes, etc.

5. Balancing Equations Law of Conservation of Mass – in a chemical equation, the total mass of the products is always the same as the total mass of the reactants.

6. Conservation of Mass lab

7. products and reactants have to have the same number of atoms on each side of the reaction. Balancing Equations

8. We balance the equation by adding numbers (coefficients) to the FRONT of the compounds in the reaction. We have to count the number of atoms on each side of the reaction and make them all equal. We will do this for this reaction on the board.

9. 1. Count atoms on each side of the equation. 2. Add appropriate numbers to the front of the compound or element until the equation is balanced. NOTE: Always balance oxygen (O) second last and hydrogen (H) last. Steps to balancing equations:

10. Mg + O 2 --> MgO CH 4 + O 2 --> CO 2 + H 2 0 H 2 SO 4 + NaOH --> Na 2 SO 4 + H 2 O Practice makes balancing easier. Balancing Equations Examples

11. assignment Balancing equations