1. Make two columns on a sheet of paper
Make two columns on a sheet of paper. Title 1 column Physical Changes and the 2nd column title Chemical Changes.
From the next slide, categorize each item either physical or chemical change.

2. PHYSICAL OR CHEMICAL Change?
Candle wax
melting
Salt dissolved in water
Fireworks exploding
Wood burning
Leaves changing colors
Cooking an egg
Cake baking
Breaking an egg
Cutting paper
Ice freezing
Water boiling
Mixing baking soda and water
Iron rusting
Tarnished silver
Battery corrosion

3. Chemistry Background
In order for elements to be completely stable (or un-reactive) they need to have 8 electrons in their outside energy level.
An element with 8 electrons on its last level is a happy element. The “happiest” elements on the table are the noble gases.
Exception: Helium is happy with two electrons in its outer energy level.

4. Selection Process
Sodium contains 1 valence electron on its outside shell. It is very unhappy and unstable. It needs a “partner” to balance it out. But, only one type of “partner” will do. It must have 7 valence electrons!

5. Match
Chlorine looks like a good partner because it has 7 valence electrons!
Draw a Lewis Dot Diagram for Sodium and Chlorine.

6. Chemistry of Sodium and Chlorine
If sodium gives away its last electron, it will be left with 8 on its last shell! Therefore it will be happy!
1e- 8 2
11P+
positive
The sodium atom then becomes a ____________ion.

7. Chemistry of Sodium and Chlorine
If chlorine accepts the electron from sodium it will now have 8 electrons on its outside shell therefore it will be happy!
1e-
7e- 8 2
17P+
negative
The chlorine atom then becomes a ___________ ion.

8. Ion
an atom that has an electrical charge because it no longer has an equal number of protons and electrons.
6P+ 6N
2e-
3e-

9. Rule of Eight
1e-
7e-
8e-
11P+
17P+
1e-
8e-
1e-
Sodium Chloride

10. LiF HHe BeO NaCl KI CaS MgO FAr KCl Molecule Possible Not Possible
Copy the table and
identify if each of
the following
compounds is possible.
Explain why!

11. Models of Compounds
Make the following compounds by fitting the puzzle pieces together. Use the names of the compounds as clues.
Sodium chloride
Calcium oxide
Carbon dioxide
Calcium chloride
Aluminum oxide
Draw the compounds in your notebook and write the name of the compound and its chemical formula. Include the Lewis Dot Diagram for each atom

12. Chemical Equations
Shorthand way that scientists use to represent what takes place in a chemical reaction.
Chemical equations consist of many different components (parts).

13. Components of a Chemical Equation
2Na2O2 + 2H2O -> 4NaOH + O2

14. Copy the chart and fill in the spaces.
Chemical Formula
Total # of Elements in
the Formula
Total # of Atoms in
NaCl
CO2
H3PO4
2H2SO4
H2O
2C6H12

15. Symbol Ex: H, Na 1 or 2 letters used to represent an element
Place of discovery, scientist, or other language such as Latin or Greek.
First letter capitalized, second letter lower case.

16. Ex: NaCl, H2O Chemical Formula
A combination of symbols and numbers that represent the number and types of elements(atoms) present in a compound.

17. Subscript
Ex: CO2, H2O2
Small number written to the right and below the normal line of letters.
Shows how many atoms of each element are present in a substance.
No subscript means there is only one atom present.

18. Chemical Reaction Ex: H2 (g) + O (g) H2O (liquid)
When substances interact to form one or more new substances with different properties than the original substance

19. Chemical Equation Ex: 2H2 + 2O2 2H2O2
A combination of chemical formulas used to describe what happens in a chemical reaction.
The equation identifies the reactants and resulting products.

20. Coefficient 2Na + 2Cl 2NaCl
A number written in front of a chemical formula to show how many molecules of that substance are present.

21. Reactants 2CO2 2C + 2O2 Formulas written on left side of arrow ( )
Starting substance or substances in a chemical reaction

22. Product 2Fe + O2 2FeO Formulas written on the right side of arrow ( )
New substance or substances formed in a chemical reaction

23. Yields H2 + O2 H2O2 Arrow shows a reaction has taken place.
The reactants have reacted to produce a new substance (the product)

24. Compound
H2O, CO2, CO
A substance composed of two or more elements chemically combined
in a definite proportion

25. Physical Change
A change in which the characteristics of a substance are only changed physically and the original properties stay the same.

26. Physical properties of matter are characteristics that you can observe about the matter.
EX: color, shape, size, density, melting point, boiling point, freezing point, specific heat, state, metal, nonmetal, metalloid, evaporation, condensation, crystallization, conductivity, magnetism, luster, malleability, taste, dissolving, odor, texture, volume, mass, length, temperature
Physical Properties

27. Chemical Changes
A change in which a substance or substances is changed into one or more new substances with different properties than the original substances

28. Chemical Properties
Chemical properties of matter are the properties that indicate whether an object can undergo a chemical reaction.
EX. flammable, reactive, corrosive, tarnishing, rusting oxidation …

29. Law of Conservation of Mass
Matter is neither created or destroyed, only changed.
The number of atoms in the reactants must be equal to the number of atoms in the product.

30. Precipitate A solid that forms as a result of a chemical reaction
It will pull out and fall to the bottom of the container

31. Law of Conservation of Mass
Reactants yields Products
NaHCO3 + HC2H3O2 CO2 + H2O + NaC2H3O2
1 sodium, 5 hydrogens, 3 carbons, 5 oxygens
BALANCED!!!
Number and kind of atoms on the reactant side must equal the number and kinds of atoms on the product side of the equation.

32. CHEMICAL CHANGES Occur When:
Different substances with new properties are formed.

33. Chemical Equations reactants products
You can explain a chemical reaction on paper by using a chemical equation.
reactants products
What you START with What you end up with
yields

34. Chemical Reactions
Involve the breaking or forming of chemical bonds causing atoms to become rearranged into a new substance or substances.

35. What to look for in a chemical change:
New substance with new properties
Energy involved
(heat being released, heat being absorbed)
Gases released
Color change
A precipitate( a solid that separates out of a reaction)