Happy Tuesday! 12/04/2012DO NOW!

1. What are the 4 indicators of a chemical reaction?

2. How is a physical reaction different from a chemical reaction?

3. 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 Qs1. Which is only a physical

change? souring or milk

melting of iceburning of oil

rusting of iron

2.Which process involves a chemical change? Photosynthesis

freezing waterboiling water

melting ice

3. In the making an omelet, which process involves a chemical change?

melting butter frying eggs chopping onions stirring eggs

LEQ #8: How are chemical reactions represented in writing?

LEQ #9: What can we do to increase the rate of a reaction?

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

1.Reactants? 2.Products?3.How many molecules of H20 are in the products?4.How many atoms of Hydrogen are in H202?5.How many atoms of Hydrogen are in the Reactants?

PRACTICE

C3H8 + 5 O2 4 H2O + 3 CO2

1.Reactants? 2.Products?3.How many molecules of H20 are in the products?4.How many atoms of Hydrogen are in C3H8?5.How many atoms of Hydrogen are in the Reactants?

PRACTICE – WORK TOGETHER

4Al + 3 O2 2 Al2O3

1.Reactants? 2.Products?3.How many molecules of Al203 are in the products?4.How many atoms of Oxygen are in O2?5.How many atoms of Oxygen are in the Reactants?

PRACTICE – ON YOUR OWN

6 CO2 + 6 H2O C6H12O6 + 6 O2

1. Reactants? 2. Products?3. How many molecules of C02 are in the reactants?4. How many atoms of Hydrogen are in H20?5. 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=JAeOP2Mf

rDY&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