1. Intro to Chemical Reactions Chpt 7 World of Chemistry

2. Objectives Students will be able to write chemical equations. Students will be able to balance chemical equations. Students will classify reactions into types.

3. Chemical reaction: -when one or more chemical bonds are broken and/or created resulting in new substances being made - loss or gain of energy -the rearrangement of atoms to make something new Evidence of chemical reaction: – Formation of a gas – Color change – Formation of a solid (precipitate) – Heat/flame produced OR coldness (heat loss) produced

4. Chemical equation – representation of chemical reaction; *must include: -reactant(s) (starting material) -yield arrow (direction of reaction) -product(s) (end materials) Reactant(s)  Product(s)

5. Always label your reactants and products -solid/precipitate (s) -liquid (l) -gas (g) -soluble in water, aqueous solution (aq)

6. Examples of writing chemical equations Solid carbon reacts with gaseous oxygen to form gaseous carbon dioxide. Solid magnesium metal reacts with liquid water to form (  ) solid magnesium hydroxide and hydrogen gas.

7. Examples Aqueous sodium carbonate is mixed with aqueous calcium chloride to form aqueous sodium chloride and calcium carbonate, a precipitate.