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Happy Tuesday! 12/04/2012 DO NOW!. What are the 4 indicators of a chemical reaction? How is a physical reaction different from a chemical reaction? Label the following “CC” for chemical change or “PC” for physical change: Burning Rotting Rusting Melting
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Happy Tuesday! 12/04/2012DO NOW! • What are the 4 indicators of a chemical reaction? • How is a physical reaction different from a chemical reaction? • Label the following “CC” for chemical change or “PC” for physical change: • Burning • Rotting • Rusting • Melting • Combining baking soda and vinegar
ACTIVATOR - Reactions • Watch the video and write down any reactions you see. • Are they chemical or physical changes do you think?
HOT Qs • 3. In the making an omelet, which process involves a chemical change? • melting butter • frying eggs • chopping onions • stirring eggs 1. Which is only a physical change? souring or milk melting of ice burning of oil rusting of iron 2.Which process involves a chemical change? Photosynthesis freezing water boiling water melting ice
KEY VOCAB • Chemical Equations: how scientists represent chemical reactions 6 CO2 + 6 H2O C6H12O6 + 6 O2 This is a really confusing and stupid way of doing things because what normal person has any idea what this means? LUCKILY… You’re not normal, you’re chemistry students! So let’s break it down…
Research 6 CO2 + 6 H2O C6H12O6 + 6 O2 Reactants Chemical Reaction Products Coefficient Subscript
KEY VOCAB • Reactants: substances that take part in a chemical reaction What goes in • Products: substances made during a chemical reaction What comes out + =
KEY VOCAB • Coefficient: # of molecules of a compound in a chemical reaction • Ex: 6 H = 6 molecules of Hydrogen • Subscript: # of atoms of an element in a compound • Ex: H2O = 2 atoms of Hydrogen in 1 molecule of water ** REMEMBER – ATOMS MAKE UP MOLECULES **
PRACTICE 2 H202 2 H20 + O2 • Reactants? • Products? • How many molecules of H20 are in the products? • How many atoms of Hydrogen are in H202? • How many atoms of Hydrogen are in the Reactants?
PRACTICE C3H8 + 5 O2 4 H2O + 3 CO2 • Reactants? • Products? • How many molecules of H20 are in the products? • How many atoms of Hydrogen are in C3H8? • How many atoms of Hydrogen are in the Reactants?
PRACTICE – WORK TOGETHER 4Al + 3 O2 2 Al2O3 • Reactants? • Products? • How many molecules of Al203 are in the products? • How many atoms of Oxygen are in O2? • How many atoms of Oxygen are in the Reactants?
PRACTICE – ON YOUR OWN 6 CO2 + 6 H2O C6H12O6 + 6 O2 • Reactants? • Products? • How many molecules of C02 are in the reactants? • How many atoms of Hydrogen are in H20? • How many atoms of Hydrogen are in the Reactants?
What in the world is a precipitate? • http://www.youtube.com/watch?v=8RmVwz2fNGc (shorter) • OR • http://www.youtube.com/watch?v=JAeOP2MfrDY&feature=related (longer)
Finding the main idea and supporting details! (20 min. 4 min/paragraph) • Read the article about reaction rates. • For each paragraph, write down the main idea and 2 supporting details • 1 reader and 1 recorder • Reader reads aloud • Recorder writes down the main idea and supporting details • Switch for each paragraph
Factors that affect the RATE of a chemical change • Rate—how quickly something happens
Factors that affect the RATE of chemical change • Temperature • Surface area • Concentration