1. EOC & CHEMISTRY BIG IDEAS Review
Semester 2 EOC
May 30, 2014
Mr. Rosato’s Physical Science

2. Scientific Method Steps 1-3
State the Problem
1. Question
Make it as precise as possible
2. Hypothesis
Testable Prediction
3. Experiment
Independent Variable: I change it
Constant always keep it the same
Control Group: Compare all your tests to this group
Predict
Observe
Think

3. Scientific Method Steps 4-6
4. Data
Dependent Variable
Depends on the Independent variable
Qualitative means describe or categorize
Quantitative means a measure a number
5. Conclusions
Does the Data support the hypothesis?
If no, revise the hypothesis
If yes, then
Theory = happens more than once
Law = happens ALL the time
6. Communicate
Enough detail to allow others to repeat experiment
Classify
Compare
& Contrast
Infer

4. States of Matter Plasma Gas Liquid Solid Highest Energy
Atoms not stuck
together
Gas
High Energy
Atoms not stuck
together
Ionization
Relaxation
Evaporation
Condensation
Boiling Point
Dew Point
Liquid
Medium Energy
Atoms loosely stuck
together
_Melting Point
Melting
Solid
Low Energy
Atoms tightly stuck
together
Freezing Point
Freezing

5. States of Matter: Big Ideas
Plasma- freely moving molecules, free electrons
Gas-freely moving molecules
Liquid-loosely packed
Solid- tightly packed

6. MATTER Mixtures Pure Substances Elements Atom + Atom Atom + Atom
Made of Atoms
Has Mass &
takes up Space
Mixtures
Made of
more than one
type of matter
Pure
Substances
Made of one
type of matter
Heterogeneous
Made of more
than one phase
Can be separated
Homogeneous
one phase
Elements
Made of one
type of atom
Compounds
Made of 2 or
More atoms bonded
together
Examples:
Trail Mix
Salad
Solution
All its regions are
Identical
Ex: Kool-Aid
Atom + Atom
= Molecule
Molecule+Molecule
= Element
Atom + Atom
= Molecule
Solute
The stuff that is
dissolved
In the liquid
Ex: Kool-Aid mix
Solvent
The liquid that
forms the solution
Ex: Water
Molecule + Molecule
= Compound

7. Properties of Matter Chemical Properties Physical Properties
States
Solid
Liquid
Gas
Plasma
Chemical
Properties
Describe how it can
form a new substance
Physical
Properties
Describe a Substance
Signs of
Chemical Reaction
Color Change
Temp change
Bubbles
Solid Formation
Odor
Properties
Flammability
Reactivity
Toxicity
Changes of State
Melting
Freezing
Boiling
Condensation
Ionization
Relaxation
Characteristics
Color
Shape
Size
Texture
Mass
Volume
Density

8. Matter BIG IDEAS Elements: one type of Atom (Ex: Al Foil)
ATOMS = Building Blocks of Matter
MOLECULE = 2 or more atoms bonded together.
Ex: NaCl, H2O, CH4, H2
Pure Substances
Elements: one type of Atom (Ex: Al Foil)
Compounds: 2 or more atoms bonded together (Ex: H2O)
Mixtures
more than one type of matter
States
Solid
Liquid
Gas
Plasma
Physical Properties
Describe a substance ( color size, shape)
Chemical Properties
Describe how it can make a new substance (flammable)
Signs of Chemical Reaction
Color Change
Temp change
Bubbles
Solid Formation
Odor

9. Atomic Structure Atomic # Proton# Electron# SAME Sub-atomic particle
Location
Charge
Mass
Proton
Nucleus +1 1
Neutron
Electron
Orbiting the nucleus -1

10. Bohr Model of the Atom
Electrons are arranged in fixed orbits around the nucleus.
fill up orbits in order from lowest energy (inside orbit) to highest energy (outside orbits).
Electrons are arranged in a fixed orbit in 2, 8, 8, 8.
Bohr model only works up to atomic number20 (Ca)

11. Valence Electrons 1 Valence Electron
Valence Electrons = #electrons in outer orbit
Atoms are “HAPPY” when they have a full valence orbit.
They will find another atom to exchange or share electrons so they have a full valence orbit
1 Valence Electron

12. Chemical Bonding
Atoms are “HAPPY” when they have a full valence orbit.
They will find another atom to exchange or share electrons so they have a full valence orbit.

13. Atomic Structure BIG IDEAS
sub-atomic particles
Protons (+), Neutrons(0) in Nucleus
Electrons (-) in orbits
APES = Atomic # Proton# Electron# SAME
Bohr Model:
Fixed orbits 2, 8, 8, 8 electrons
Works up to Ca (#20)
Valence Electrons:
= electrons in outer orbit
Atoms are “HAPPY” when they have a full valence orbit.
They will find another atom to exchange or share valence electrons so they have a full valence orbit
1 Valence Electron

14. Types of chemical bonds: Ionic
Metals to Non-metals,
Metals give electrons, Non-metals take electrons.
Metals =positive ions,
Nonmetals =negative ions.

15. Types of chemical bonds: Covalent
non-metals to non-metals, share valence electrons,
50% custody of electrons
EXCEPT for water which has polar covalent
Electrons spend more time with oxygen ( O =- side of molecule H = + side of molecule).

16. Types of chemical bonds: Metallic
non-metals to non-metals, share valence electrons,
50% custody of electrons
EXCEPT for water which has polar covalent
Electrons spend more time with oxygen ( O =- side of molecule H = + side of molecule).

17. Types of Bonds BIG IDEAS
Atoms Bond using Valence Electrons TO BE HAPPY
Bond Type
Partner #1
Partner #2
What Happens
Who does what
In the End
IONIC
Metal
NonMetal
Transfer Electrons
Metal Gives
Nonmetal Takes
METAL
= + Ion
NONMETAL = - Ion
COVALENT
Nonmetal or H
Nonmetal
Share electrons between 2 atoms
Both share valence electrons EQUALLY
Joint Custody
METALLIC
Share electrons between ALL atoms
All share valence electrons
Sea of Electrons

19. Periodic Table BIG IDEAS
organized in
columns= Groups & rows= Periods
Ones digit of group # = # of valence electrons
Period#= tells us the last orbit which # is filled with valence electrons
Zig-zag Line divides Metals & Nonmetals

20. Representing bonds: Bohr Model of Valence Electrons
We do this to figure out how many atoms will
bond with each other when forming compounds.

21. Representing bonds: Lewis dots
We do this to figure out how many atoms will
bond with each other when forming compounds.

22. Representing bonds: Oxidation #
1. Find the oxidation numbers for each element from the periodic table.
2. Write the number above & to the right of each element (it’s a superscript).
3. Criss-cross the numbers without the sign:
the superscript for each element becomes the subscript for the other element.

23. Bonding BIG IDEAS
Bohr Model & Lewis Dots work only up to Ca (atomic #20)
Oxidation Numbers (crisscross) work for ALL elements
The crisscross tells us how many atoms bond to make a HAPPY molecule
Then we write the Balanced equation to make it happen

24. Balancing Equations Must obey Law of Conservation of Mass
# of reactant atoms = # of product atoms for each type of atom
 You can only chance the coefficient, not the subscript!

25. Balancing Tips H C Subscripts WE CAN’T CHANGE THE SUBSCRIPT!!
These are the numbers below the symbol
They tell how many atoms are bonded together in one molecule
For example C2H6 has 2C atoms bonded to 6H atoms
The subscripts are determined by the valence electrons
WE CAN’T CHANGE THE SUBSCRIPT!!
We find the subscripts by using:
Bohr Model
Lewis Dots
Criss-cross /oxidation #

26. Balancing tips Coefficients IT IS THE ONLY NUMBER THAT WE CAN CHANGE!!
These are the numbers in front of the symbol
They tell how many atoms or molecules we have
It multiplies the number of atoms or molecules (including the subscript)
Ex: 3Na = 3Na atoms
2 C2H6 = 2x2 = 4C atoms
=2x6 = 12H atoms
IT IS THE ONLY NUMBER THAT
WE CAN CHANGE!!

27. Balancing BIG IDEAS
The crisscross tells us how many atoms bond to make a HAPPY molecule
Then we write the Balanced equation to make it happen
Must obey Law of Conservation of Mass
# of reactant atoms must = # of product atoms for each type of atom
 can only chance the coefficient, not the subscript!

28. Types of reactions decomposition (break apart)
2H2O2 + yeast  2H2 + 2O2
synthesis (put together)
2H2 +O2  2H2O
combustion (fire)
CH4 + O2(g)  CO2(g) + 2H2O(g)
single replacement (one pushes the other out)
Zn(s) + HCl (aq)  ZnCl2(aq) +H2 (s)
double replacement (the two switch)
PbI(aq) + K(NO3)(aq)  K(NO3)(aq) + PbI(s)

29. Chemical Reactions BIG IDEAS
We want to PREDICT what happens when things react:
The type of reaction allows us to predict what type of chemical reaction will occur and the products;
Then, the crisscross tells us how many atoms bond to make a HAPPY molecule in the products;
Then we write the Balanced equation to make it happen

30. Doing Chemistry EXAMPLE
What happens when I put a piece of Zn in HCl?
Zn + HCl  ???
Type of reaction MUST be Single replacement:
Zn + HCl  ZnCl? +H2
The crisscross tells us the formula is ZnCl2 and that little H will find a buddy
The BALANCED equation is:
Zn + 2HCl  ZnCl2 +H2

31. Aqueous Solutions
Water has superpowers because it forms a polar covalent bond (unequal sharing of the electrons)
This allows water to surround and separate many compounds.
Acids & bases can only form in water
Acids: Forms H+ ions (steal electrons) when dissolved in water
Bases: Release OH- ions (force to take electrons) when dissolved in water H+
OH-

32. pH Scale Measures whether a substance is an acid or a base.
pH scale goes from 0-14
pH <7 =acidic
pH =7 =neutral (pure water)
pH >7 = bases

33. Aqueous Solutions BIG IDEAS
Water is a polar molecule
which has superpowers
Most of chemistry happens in Aqueous solutions
Acids & bases can only form in water
Acids: Forms H+ ions (steal electrons)
Bases: Forms OH- ions (force to take electrons)
pH scale goes from 0-14
pH <7 =acidic
pH =7 =neutral (pure water)
pH >7 = bases H+

34. THE FINAL BIG IDEA
All the Elements in the Universe were forged in the stars
Chemistry is the study of how these elements combine to make NEW SUBSTANCES
New substances form to make elements HAPPY when they make new molecules