Bell Ringer 4-29-09 When we balance equations, we only change _________, not subscripts. T/F: Balanced chemical equations should have the same number of atoms on each side of the arrow. Chemical equations are just abbreviations using chemical _______ and numbers. In 2C6H2O5, how many atoms of Hydrogen are there?

ALCOS Objectives: #1- Identify the steps of the scientific method #4 State the law of conservation of matter (Balancing Chemical Equations)

Chapter 6 Section 3 Controlling Chemical Reactions

To start a chemical reaction you need activation energy. Activation energy is the minimum amount of energy needed to start a chemical reaction.

Exothermic Reactions Endothermic Reactions P. 206 in textbook

Chemical reactions do not all occur at the same rate. Explosions  really fast Rusting  much slower

Rate of Reaction Rate of reaction tells us how fast a reaction occurs. To find the rate of reaction, you can measure either how quickly the reactant is disappearing or how quickly the product is appearing. Ex. If it takes 1 minute for 2 inches of the candle to burn, how many minutes will it take for 6 inches of the candle to burn. Ans. 3

What affects the rate of reaction? Concentration- the amount of substance present. Surface area – how big or small the area is or how much is being exposed Temperature – hot or cold

Inhibitor – slows down a chemical reaction. (ex: food preservatives) Catalyst – speeds up a chemical reaction. (ex: enzymes) Ex. Enzymes – breaks down food. Make it possible for your body to function properly.