EOC & CHEMISTRY BIG IDEAS Review

MR. ROSATO’S PHYSICAL SCIENCE

Semester 2 EOCMay 30, 2014

Scientific Method Steps 1-3

Sta

te t

he

Pro

ble

m1. QuestionMake it as precise as possible

2. HypothesisTestable Prediction

3. ExperimentIndependent Variable: I change itConstant always keep it the sameControl Group: Compare all your tests to this groupPredict ObserveThink

Scientific Method Steps 4-64. DataDependent VariableDepends on the Independent variable

Qualitative means describe or categorize

Quantitative means a measure a number

5. ConclusionsDoes the Data support the hypothesis?If no, revise the hypothesisIf yes, thenTheory = happens more than onceLaw = happens ALL the time

6. CommunicateEnough detail to allow others to repeat experiment

Infer

Compare & Contrast

Classify

SolidLow EnergyAtoms tightly stucktogether

LiquidMedium EnergyAtoms loosely stucktogether

GasHigh EnergyAtoms not stucktogether

PlasmaHighest EnergyAtoms not stucktogether

Freezin

gMelting

Relaxation

Condensa

tion

Ionization

Eva

pora

tion

_Melting Point

Boiling Point Dew Point

Freezing Point

States of Matter

States of Matter: Big Ideas Plasma- freely moving molecules, free electrons

Gas-freely moving molecules

Liquid-loosely packed

Solid- tightly packed

Pure Substances

Made of one type of matter

ElementsMade of one type of atom

CompoundsMade of 2 or

More atoms bondedtogether

Homogeneousone phase

MATTERMade of AtomsHas Mass &

takes up Space

HeterogeneousMade of more than one phase

Can be separated

MixturesMade of

more than one type of matter

SoluteThe stuff that is

dissolvedIn the liquid

Ex: Kool-Aid mix

Atom + Atom = Molecule

Molecule+Molecule = ELEMENT Molecule + Molecule

= COMPOUND

SolutionAll its regions are

IdenticalEx: Kool-Aid

SolventThe liquid that

forms the solutionEx: Water

Examples:Trail Mix

Salad

Atom + Atom = Molecule

CharacteristicsColorShapeSize

TextureMass

VolumeDensity

PhysicalProperties

Describe a Substance

ChemicalProperties

Describe how it can form a new substance

Changes of StateMeltingFreezingBoiling

CondensationIonizationRelaxation

StatesSolidLiquidGas

Plasma

Properties of Matter

PropertiesFlammability

ReactivityToxicity

Signs of Chemical Reaction

Color ChangeTemp

changeBubbles

Solid FormationOdor

Matter BIG IDEAS

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

ATOMS = Building Blocks of MatterMOLECULE = 2 or more atoms bonded together. Ex: NaCl, H2O, CH4, H2

Atomic Structure

Sub-atomic particle

Location Charge Mass

Proton Nucleus +1 1

Neutron Nucleus 0 1

Electron Orbiting the nucleus

-1 0

Atomic #Proton#Electron#SAME

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)

Valence Electrons

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

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.

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

Types of chemical bonds: Ionic

• Metals to Non-metals,• Metals give electrons, Non-metals take electrons. • Metals =positive ions, • Nonmetals =negative ions.

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).

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).

Types of Bonds BIG IDEASAtoms 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 GivesNonmetal Takes

METAL = + IonNONMETAL = - Ion

COVALENT

Nonmetal or H

Nonmetal

Share electrons between 2 atoms

Both share valence electrons EQUALLY

Joint Custody

METALLIC

Metal Metal Share electrons between ALL atoms

All share valence electrons

Sea of Electrons

http://www.google.com/url?sa=i&rct=j&q=periodic+table+of+elements&source=images&cd=&cad=rja&docid=-b2eGSKlC5pPmM&tbnid=TFy9_ZPU8--QmM:&ved=0CAUQjRw&url=http://www.livescience.com/25300-periodic-table.html&ei=je-cUYzpK4WI9QSjh4DICQ&bvm=bv.46751780,d.eWU&psig=AFQjCNE8lQoT4IvSPlv1ADqMjQECzZXa2A&ust=1369325784122327

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

Representing bonds: Bohr Model of Valence Electrons

We do this to figure out how many atoms will bond with each other when forming compounds.

Representing bonds: Lewis dots

We do this to figure out how many atoms will bond with each other when forming compounds.

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.

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

Balancing Equations

Must obey Law of Conservation of Mass1. # of reactant atoms = # of product atoms for each type

of atom

2.  You CAN ONLY CHANCE THE COEFFICIENT, NOT THE SUBSCRIPT!

Balancing Tips

Subscripts 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 #

HH

C C H

HH

H

Balancing tips

Coefficients 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 atomsIT IS THE ONLY NUMBER THAT

WE CAN CHANGE!!

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!

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)

Chemical Reactions BIG IDEAS

We want to PREDICT what happens when things react:

1. The type of reaction allows us to predict what type of chemical reaction will occur and the products;

2. Then, the crisscross tells us how many atoms bond to make a HAPPY molecule in the products;

3. Then we write the Balanced equation to make it happen

Doing Chemistry EXAMPLE• What happens when I put a piece of Zn in HCl?

• Zn + HCl ???

1. 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

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-

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

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+

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