1. Warm Up
Complete this warm up. Be sure to include today’s date. Copy the following and complete the matching activity.
1___Physical Change a) atoms are not created or destroyed
2___Chemical Change b) A solid that forms from two liquids reacting
3___Reactive c) is formed as the result of a chemical reaction.
4___chemical Equation d) representation of a chemical reaction
5___ Subscript e) Cutting, melting…affects the form, but does
not change identity
6___ Physical Property f) before the C. formula, number of molecules
7___Chemical Property g) digestion, rusting… change in identity
8___Reactant h) CO2, NH4, CaPO4 Shows number of atoms
9___Product i) shows proportion of atoms in a compound
10 ____ precipitate j) density, phase… measureable and /or observable
11 ____ Coefficients k) How likely to undergo a chemical reaction
12 ____ Law of conser l) Can’t be observed without changing
of Matter/Mass the identity
13 ____ Chemical Formula m) present at the beginning of a chemical
reaction E G K D H J L M C B F A I

2. Warm Up
Sit in your group of four from yesterday. You will need your notebook, glue stick and Chromebook today. Do not open your Chromebook until I instruct you to. .so,
Thinking back on the lab from yesterday, I want you as a group to decide if the Gak was created as a result of a chemical change or physical change.
On your sheet write three reasons to support your answer. (remember key indicators)

4. Evidence of a Chemical Change
Can not be reversed
Changes chemical properties
Formation of gas
Formation of precipitate (a solid that results from two liquids reacting)
Change in color
Change in odor
Change in energy
Endothermic Absorbs heat energy (gets cold)
Exothermic Releases heat energy (gets hot)

5. Chemical Reaction
chemical reaction, one or more substances change into one or more new substances because the atoms are rearranging into different products with different properties.
Glue, Borax, water reacted to created GAK (Polymer…like in plastic)
Gak has very different properties from the reactants.

6. Academic Conversation: What do you know?
1. Get with a partner 2. Copy the sample work below. 3. With your partner write as much information as you can about what you notice. 3 Ag2S + 2 Al 6 Ag + Al2S3

7. What do you know?
3 Ag2S Al Ag + Al2S3

8. Group Work Read pages 33-34 in Coachbook.
Popcorn read in with your partner
Add more detail to your equation

9. 3 Ag2S + 2 Al 6 Ag + Al2S3 + + What do you see?
Does this remind you of anything in math?
Chemical Equation
3 Ag2S Al Ag + Al2S3
Reactants
Products
What does the subscripts and coefficient tell us?
coefficients
subscripts + +
6 Ag 3
2 Al Ag Al
2 Al Ag Ag
3 S
2 Al Ag
6 Ag
6 Ag Ag
3 S
Silver
sulfide
Aluminum
sulfide
Aluminum creates
Silver

10. The Law of Conservation of Mass
What do you notice?
3 Ag2S Al Ag + Al2S3
6 Ag
6 Ag
3 S
2 Al
2 Al
3 S
The amount of atoms of each element in the reactants are equal to the amount of the same in the product!!!!
The Law of Conservation of Mass
Matter (mass) can neither be created nor destroyed, but rearranged.

11. How do you know if an equation reflects The Law of Conservation of Mass?
reactants  products
2H2 + O2  2H20
A chemical equation is balanced when it reflects the conservation of mass.
Graphic:

12. Recap Chemical equation represents a chemical change.
It identifies the starting and ending chemicals.
The starting chemicals are called the _____
The ending chemicals are called the ______
reactants
products.

13. What are Reactants & products
Reactants – elements and/or compounds that undergoes a chemical change
Products – elements and/or compounds that are the result of the chemical change/reaction
yields
reactants  products

14. Balancing Equations
Subscripts – a small number used to represent the number of atoms in the preceding element. (can never change)
Coefficient – the number that appears at the beginning of a molecule or element that indicates its amount (can be changed).
Subscript
Coefficient
2H2

15. Count the number of atoms
5 O2H3 = _____O ______H
CO = _____ C ______ O
8 NaOH2 = _____ Na _____O _____H

16. Warm up Ex. a) NaCO3 = Na=1 b) 5 ZnSO4 Zn= 5 (5x1) C=1 S= 5 (5x1)
1.You will need your notebook, glue and Chromebook.
2.Do not open your Chromebook until I tell you to.
3. Take out homework
Copy and then determine the number of atoms in each compound.
Ex. a) NaCO3 = Na= b) 5 ZnSO4 Zn= 5 (5x1)
C=1 S= 5 (5x1)
O=3 O=20 (5X4)
H2O 6) 2H2NCH3Br
MgCl ) 4NaC2H3O2
Li2O ) Li2SO4
3Al2O ) HBr
2CH3OH 10 CH4

18. User name: ridgeroadms Password: ravens Click Science
Takeout Chromebooks
Go to BrainPop log in
User name: ridgeroadms
Password: ravens
Click Science
Click Matter and Chemistry
Watch Chemical equations
Take Classic Quiz

19. The same number of each kind of atom must be on the left side of the arrow as are on the right side when an equation is balanced. Al O Al O Al O O Al O Al Al

20. This is now a balanced equation
Balancing an equation:
H O  H2O 2 2 H H H O H O O
First: Count the atoms on both sides of the yield arrow
Second: Determine which atoms are not equal and add coefficients to balance these atoms.
2 H atoms H atoms
2 O atoms O atom
Hydogen atoms are =
Hydogen atoms are =
Hydogen atoms are ≠
4 H atoms
2 O atoms
4 H atoms
2 O atoms
Oxygen atoms are =
Oxygen atoms are =
Oxygen atoms are≠
When a coefficient is added you must multiply all atoms in the compound by this number. Redo the inventory
After redoing the inventory, add coefficients to balanced other atoms. With each additional coefficient the inventory must be updated.
Oxygen, as a product, must be multiplied by 2. A coefficient is placed in front of the compounds that contains O.
This is now a balanced equation

21. So: Chemical equations are balanced, when the numbers and kinds of atoms on each side of the reaction arrow are equal. H H O H O O H O H H H H
Products
Reactants
4 Hydrogen
4 Hydrogen
2 Oxygen
2 Oxygen

22. Because atoms are conserved, the mass of
the reactants in the chemical reaction is
equal to the mass of the products.
H2 + F2  HF
2g + 38g = 2( 20g)
40g = g H F H F F H
Reactants Products
40 g
40 g

23. Law of Conservation of Matter (Mass)
If the amount of matter (mass) was not the same before and after the change
(remember, it is the law),
you must offer an explanation as to why.

24. Sometimes in chemical reactions mass is converted to a gas and/or energy that it is released as a product.