1. C HAPTER 8: C HEMICAL E QUATIONS & R EACTIONS By: Jessica Alphonse

2. C HEMICAL C HANGE A chemical reaction is a process in which one or more substance turns into a new substance. Some examples of chemical reactions include wood burning which turns into ash, metal rusting, and baking a cake. Signs of a chemical reaction include: color change odor given off Substance difficult to reverse. Gas released Solid forming into a liquid.

3. P HYSICAL C HANGE A physical change is a process in which the molecules of a substance have not change. Some examples of physical change include water melting, evaporating or freezing, concrete hardening, and different color paint mixing together. Signs of a physical change include making a mixture cutting dissolving Grinding Original properties are kept. Change of state.

4. B ALANCING C HEMICAL E QUATIONS Chemical equations show the amount of reactants & products. For a reaction to take place, molecules and atoms of the reactants must go together. In order to construct a chemical reaction, you must first write a word equation. Ex. Methane + Oxygen -  Carbon Dioxide. Use the arrow to separate the reactants and the products. Then turn them into a formula equation. Ex. ?CH4+ O2 -  ?CO2 + ?H2O.

5. T YPES OF R EACTIONS There are many different types of reactions you can easily identify what products are formed. Decomposition - one substance breaking up into 2 or more substances. Ex. 2H2O  2H2+O2 Synthesis- A combustion of 2