CHAPTER 4

Law of Conservation of Mass The law of conservation of mass states that matter can neither be created or destroyed during a chemical reaction. (Antoine Lavoisier said this!) 2H2 + O2 --> 2H2O 4(1.01g) + 2(16g) --> 4(1.01)+2(16) 36.04 g = 36.04 g (the mass is the same on the right side and left side)

Balancing Chemical Equations Atoms are neither created or destroyed, only rearranged in a chemical reaction. The number of a particular atom is the same on both sides of a chemical equation Example: Mg + O2  MgO O Mg +  Mg O However, this is not balanced! Left: Mg = 1, O = 2 Right: Mg = 1, O = 1

Neutralization (404) Neutralization is when an acid and a base combine to produce salt and water. Example: HCl + NaOH --> NaCl +H2O (acid) + (base) --> (salt) + (water)

p. 121 Combustion (404) Combustion releases a large amount of energy. Example: burning wood You need 3 things for combustion: a fuel (wood or propane) an oxidizing agent (air, oxygen) a certain temperature

There are 3 types of combustion: Rapid combustion: it releases a great deal of energy in a short period of time (a log fire, a burning candle) Spontaneous combustion: It is often unpredictable and could be disastrous. (on a very hot and dry summer day, wood can catch fire spontaneously - forest fires) Slow combustion: Occurs over a long period of time. (fermentation and cellular respiration)

Cellular Respiration (404) It is a slow combustion It takes place in our cells. In humans, it keeps our body temperatures at around 37oC. Glucose(sugar) and oxygen are used to generate energy. It produces carbon dioxide and water.

EQUATION FOR RESPIRATION CARBON DIOXIDE GLUCOSE C6H12O6 + 6O2 6CO2 + 6H2O + ENERGY OXYGEN WATER

PHOTOSYNTHESIS (404) Through photosynthesis, plant cells use solar energy to make glucose (sugar) and oxygen from carbon dioxide and water.

EQUATION FOR PHOTOSYNTHESIS WATER OXYGEN 6CO2 + 6H2O + ENERGY C6H12O6 + 6O2 CARBON DIOXIDE GLUCOSE