CHEMISTRY
Mrs. Adams
Room 601
Today’s TO DO: 9/7/10
Introduction
 Agenda Book
 Syllabus & Expectations
 Notebooks

Hand out
 Set up
 Journal #1


Homework 
Notebook
My gift to you…I expect you to BRING it and
USE it E-V-E-R-Y DAY!
 Set Up


Date
9-7
9-8
Leave 1st 4 sheets blank for Table of Contents
Title
What is Chemistry?
if same as above, leave blank

Format
Journal
Notes
pg #
1
Starting with 5th sheet as pg.1, number each
page in lower outer corner
Journal #1 – What is Chemistry?



Go to pg.1 of your notebook
Write title Journal #1 – What is Chemistry? on
top w/date on right, 9-7-10
Write the following prompt:
a)
b)


What do you think of when you hear the word
chemistry?
List 10 things that you think are part of chemistry.
Leave a blank line
Answer
Homework: Real Life
Application of Chemistry


Find a current article showing an application of chemistry
to our lives
Write a summary in your own words that includes



main ideas of the article
your thoughts about the article
1-2 questions you still have that were NOT answered in the article

If done on computer, email me the article as well as your
summary (GREEN )
If hand written, also provide a printout of the article

DUE: Friday, Sept. 10th

Journal #2 – Self Reflection
a.
b.
c.
d.
How do you think your friends and family
would describe you?
What are your goals & expectations in this
class?
What do you hope to accomplish in the next
5 years?
What do you hope to accomplish in the next
15 years?
Lab Safety
Read the Flinn Lab Safety Directions
 To reinforce the concepts in your assigned
section, your table will create one of the
following to present to the class:

Skit
 Poem
 Cartoon
 Song
 Poster or Ad

Your presentation should try to
convince us that your rules are THE
MOST IMPORTANT rules to follow in
this class.
Lab

To do a lab really well, have your report done well
in advance.
In Other Words…
 Know WHAT you’re supposed to do BEFORE you
do it.
 Know WHY you’re doing something BEFORE you
do it.
Lab

BEFORE every lab, you will address:
Background information
 Materials & procedures
 Safety concerns
 Hypothesis
 Creation of data tables

Lab

AFTER every lab you will
Organize your data into charts and graphs
 Analyze your data
 Accept or reject your hypothesis
 Discuss your conclusion & possible source(s) of
error

Scientific Method
A way to answer questions about the world
based on observations and experiments.
 INQUIRE
Where does your Hypothesis fit?



OBSERVE


Not always visual
Where does your Conclusion fit?
EXPERIMENT


Ask questions
Changing a variable to determine
UNDERSTAND
Scientific Method in Action

CHEMOTHERAPY
For each:
1. Explain the general idea of
why scientific method applies
2. Write a SPECIFIC
• observation or question
AND
• hypothesis you could test

OIL SPILLS

FOOD INDUSTRY

COSMETIC INDUSTRY
Measurements
Always uncertain
 Instruments never flawless
 Some estimation always required


Example: A ruler

Numbered lines = centimeters


Smaller lines = 0.1 cm = 1 mm


Reliable
Reliable
Any point between each line
Must be estimated
 Not reliable

2.45 cm
Line above the ruler = _____
2.45 +/- 0.01
 Written as _______________
cm
 Ex:
Reliability

2 ways to check numbers
repeat measurement
 test against standard


Precision


how close repeated measurements are to each
other
Accuracy

how close measurements are to standard or
accepted value
Precision vs. Accuracy
Sample Problem

In 3 separate trials, Sara calculates the
density of water to be
0.88g/ml
 0.87g/ml
 0.88g/ml


Is she precise ?


Density = mass/volume
Yes, all close together
Is she accurate?

No, accepted value is 1 g/ml
Significant Digits

Sig Figs
Number of digits within a value that are
considered significant with respect
measurement validity
 Follows Pacific-Atlantic Rule

Decimal PRESENT PACIFIC
Start at far left of number (like pacific ocean
is on far left of US)
 Start counting digits @ first Non Zero
number
 End at rightmost digit (including zeros)

Examples

34.067g


0.0007458ml


5 sig figs
____
4 sig figs
____
0.009070g

4 sig figs
____
Decimal ABSENT –
ATLANTIC
Start @ far right of number (like the Atlantic
Ocean is at far right of US)
 Start counting digits @ first Non Zero
number
 End at leftmost digit

Examples

2030cm


2007dm


3 sig figs
____
4 sig figs
____
19,000,000,000g

2 sig figs
____
Practice Problems

0.0026701m


19.0550kg


6 sig figs
____
3500V


5 sig figs
____
2 sig figs
____
1,809,000L

4 sig figs
____
Sig Fig's in Calculations

Exact numbers or conversions do not count as sig
figs

Ex: Speed of light ~ 300,000,000 m/s


Can have infinite # of sig figs and must be specified
Sample –
 Speed of light expressed to 3 significant digits = 3.00 x 108
Multiplication & Division

Answer must have same # of sig figs as
lowest sig figs found within problem

Ex: 2.45 x 23.678 = 58.0111 = 58.0
(3)
(5)
(3)
Example:
Volume = length x width x height
1.
Find the volume an object with sides
10.876m x 1.34m x 13.22m
(5 sig figs)
(3)
192.6661648m (10)
 192.67 m3 (5)
 192.7 m3
(4)
 193 m3
(3)

(4)
Addition & Subtraction
Largest uncertainty determines number of
sig figs
 Answer will have lowest sig figs to the
right of the decimal from numbers in
problem


Ex: 3.21 + 5.3442 + 279.9 = 288.4542
More Examples

34.50g + 3.2345g + 671.1g + 25.345g
= 734.7745g ~ 734.8g

2092 ml – 147.54 ml
= 1944.46 ml ~ 1944 ml
Practice Problems
6.15m x 4.026m = 24.8 m2
 12.7km / 3.0 = 4.2 km
 150ml + 76.9ml + 209ml + 0.036ml =

435.936 ~ 440 ml
(35.6L + 2.4L) / 4.803 = 7.91 L
 2.542m x (16.408m - 3.88m) = 31.85 m

Journal # 3 – Sig Figs

What are the rules for significant figures?

Be sure to include those for addition/subtraction
and multiplication/division
Scientific Notation
One digit to the left of the decimal
 # of digits to right of decimal is
determined by sig fig rules
 Example 19,000,000 ml

2 sig figs
 1.9 x 107 ml


Example 0.0004569g
4 sig figs
 4.569 x 10-4 g

Scientific Notation Practice

32,700 = 3.27 x 104

1,024,000 = 1.024 x 106

0.0047100 = 4.7100 x 10-3
-9
3.901
x
10
 0.000000003901 =
Knowing Equations:
Density
Density = mass /volume
 D=m/v

Know formula & manipulate w/algebra OR
 know graphic below

M
D
V
Dimensional Analysis


Step by step conversion between units
Convert 10.0µm to inches
 Conversion factors




1m=1,000,000µm
1m = 39.37inches
Start with the given unit, then use you conversion factors to
cancel units until to arrive at the unit you want to convert to.
10um x 1m x 39.37inches = 0.0003937in
1,000,000um 1m
Practice Problems
250.0 cm to inches
 ? gal in 39L
 ? cm in 16in
 ? seconds in 5 days
 ? ft in 86cm
 ? cm3 in 2.3gal
 ? m in 3.5mi

Percent Error

% Error = measured – accepted x 100
accepted

Ex:
 Accepted
value for density of water = 1 g/ml
 Measured value for density of water in lab = 0.9 g/ml
%
Error = (0.9 – 1)/1 * 100 = 10% Error
Journal #4 – Dimensional Analysis

Are there REALLY 86400 seconds in a day?

Show your dimensional analysis to defend your
answer.
i
Chapter 2
Energy


Potential to do work or produce heat
3 Main Types –
1.
Radiant

2.
Ex: sunlight
Kinetic

Energy of motion


3.
Ex: Mechanical – energy of moving parts
Ex: Thermal – energy from internal particle motion in matter
Potential



Ex: Gravitational – falling water
Ex: Electrical – opposite charges
Ex: Chemical - battery
http://entergy.apogee.net/kids/templates/kidskorner/images/lhw2.jpg
Energy Units

calories
Amount of heat needed to raise 1g of water 1oC
 1 Calorie in food = 1000 calories


Joules
SI unit of energy
 1 cal = 4.184 J


Measuring calories

Calorimeter
Law of Conservation
Energy is neither created nor destroyed in
any process
 Energy can be transformed from one form
to another

Ex: kinetic energy of bat transferred to baseball
(kinetic, sound)
 Ex: Chemical energy of striking match
transformed into heat and light

Temperature

Celsius
0oC = freezing pt
 100oC = boiling pt
 21oC = room temp
 37oC = body temp


Kelvin
SI Unit of temperature
 oC + 273

Matter & Conservation
Has mass & volume
 States

Solid
 Liquid
 Gas


Changes
Physical
 Chemical

Just like Energy,
Matter can be neither created nor
destroyed
Elements
Substances that cannot be separated into
simpler substances by chemical change
 Organized in Periodic Table
 Combine chemically to form COMPOUNDS

Mixtures
Blend of 2 or more pure substances
(elements or compounds)
 Heterogeneous


Visible differences in combined substances
 Ex:

chocolate chip cookies
Homogeneous

No visible differences in substances
 Ex:
salt water
Separation of
Homogeneous Mixtures
1.
Distillation

2.
Crystallization

3.
Tap water = homogeneous mixture
Evaporation of liquids from solids
Chromatography

Separates mixtures by



Solubility
size
charge
Chapter 3
Early Models of the Atom
Atoms

The Greek Philosopher Democritus
Proposed all matter made up of small, indivisible
particles
 Called these “atomos” = atoms


Today’s Definition- smallest particles of an
element that retain properties of element
Democritus

Because he didn’t know what held these
particles together

They remained rejected until the 17th century
when better technology = closer observations
1700’s

Lavoisier


Law of Conservation of matter
Joseph Louis Proust

Law of constant composition
 compounds
always contains same elements in same
proportions by mass
John Dalton

Atomic Theory of Matter:
Each element is composed of extremely small
particles called atoms
 All atoms of an element are identical, but differ
from those of other elements
 Atoms are neither created or destroyed in a
chemical reaction
 A compound always has the same relative
numbers of atoms.

Discovering Atomic
Structure
Michael Faraday

structure of atoms is related to electricity

atoms contain particles that have electrical
charge.
Static Electricity

Benjamin Franklin famous electricity
experiment

Conclusions from his kite & key experiment
1.
2.
lightning is a static discharge from clouds
electricity has two kinds of charges.


Positive (+)
Negative(-)
Cathode Rays & Electrons

Running electricity through a partially evacuated glass tube
occurs in a cathode tube.



Negative end = cathode
Positive end = anode
With a fluorescent lining & addition of
electricity, particles are visible
J.J. Thompson
Deflected particles w/magnet
 Discovered particles were negatively
charged
 Named them electrons
 Along w/Milikin discovered their mass to be
only 1/2000 of full atomic mass …

Ernest Rutherford

Discovers alpha particles
Deflects towards negative plate
 Charge =


Discovers beta particles
Deflect towards positive plate
 Charge =


Discovers gamma particles
Not affected by electric plates
 Charge =

The Nuclear Atom
If electrons are negative, why are atoms
neutral?
 Must contain positive parts equal to the
negative parts.
 Where are they?

The Gold Foil Experiment (figure
3-14)
What does this mean?

The experiment determined that most of the
atoms positive charge, as well as the mass,
is in the middle, called the nucleus.

Most of the particles pass through the empty
space but occasionally one gets close
enough to the positive nucleus to deflect
Modern Atomic Theory
Atoms


Smallest units of
matter
Composed of
protons (+) and
neutrons in nucleus
and electrons (-) in
orbitals
www.phschool.com

1 proton has the mass of about 2000 electrons
Periodic Table Information

Atomic Number



Represents # of
protons
Also # of electrons in
a stable atom of an
element
Discovered by
Moseley
Atomic Mass
Sum of protons & neutrons
 Electron mass is small and
almost negligible

www.sparknotes.com
Electrons

Electrons move in
space around the
nucleus

Rutherford visualized it
as a mini solar system.
Atomic Mass

Measured by Atomic Mass Units (AMU)

atomic mass approximately = protons +
neutrons

Atomic Mass (AM) = average mass of
element’s atoms, including isotopes
Unstable Atoms

Isotopes
Ions


Different # of
electrons
Atoms with a charge
www.radiation-scott.org
Different # of neutrons
 Often radioactive
 Used as diagnostic tracers

Ions

When an atom gains or loses electrons it
acquires a charge
Fewer electrons means positive charge
 More electrons means negative charge


Charge of ion = # protons - # electrons
Sample

Write the chemical symbol for the ion with 9
protons and 10 electrons
 Answer

What is the symbol of the ion with 13 protons
and 10 electrons?
 Answer

F-
Al3+
7 Protons and 10 electrons?
 N 3-
Isotopes
Dalton said all atoms of an element are the
same.
 Not quite true, ISOTOPES have a different
number of neutrons
 In nature, elements are almost always found
as a mixture of isotopes

Identifying Isotopes

To identify isotopes more specifically
Use the Mass Number
 Mass Number = (# protons) + (# neutrons)

Fundamental Subatomic
Particles
Particle Location Charge
(C)
Proton
Neutron
Electron
Mass (g)
Mass
(AMU)
+1.602 x 10-19
1.673 x 10-24
1
Inside
nucleus
0
1.675 x 10-24
1
Outside
nucleus
-1.602 x 10-19
9.109 x 10 –28
0
Inside
nucleus
Changes in the Nucleus
Radioactive Elements

Discovered by Becquerel in late 1800s


Uranium
Pierre & Marie Curie

Radium & Polonium
Nuclear Reactions

Changes in nucleus
Changes composition of nucleus
 Alpha & beta radiation comes from nucleus


Unstable nucleus  radioactivity
Not many elements radioactive
 Why not?? Seems like all those + protons would
cause a lot of repelling…..

Composition of Stable
Nuclei


As the number of
protons increases, it
takes more and more
neutrons to remain
stable.
All atoms above 83 are
unstable
Radioactive Decay

RULE:

sums of mass numbers & atomic
numbers are same before & after
reaction
Types of Radioactive
Decay
1.

Alpha Radiation
Stream of high energy alpha particles





Consists of 2 protons and 2 neutrons
Identical to a helium-4 nucleus
Symbol 42He2+ or 42He or 42
Do not cause a health risk
Do not travel far

When an atom emits one of these, it is said
to be undergoing radioactive decay

Which brings us to the nuclear equation, or a
way to keep track of the components
Alpha Decay
2.

Beta Radiation
stream of high speed electrons





neutron changes into 1 proton & electron
proton stays in nucleus
electron is propelled out at high speed
Symbol of 0-1e- or 0-1e or 0-1
damaging to skin
Beta Decay
3.

Gamma radiation
Extremely energetic form of light
energy we cannot see



Symbolized by 00
Does not consist of particles
Able to penetrate deeply into substances
http://www.deq.idaho.gov/inl_oversight/radiation/penetration.cfm
Types of Radiation
Penetrating
Ability
Name
Identity Charge
Alpha
()
Helium4 nuclei
2+
Low
Beta () Electron
1-
Medium
Gamma High
()
energy
particle
None
high
Practice Problems

Write the nuclear equation for the alpha
decay of uranium 238.

Write a nuclear equation for the beta decay
of sodium 24
Other Nuclear Reactions

Nuclear Fusion

Atoms collide and join together releasing great
amounts of energy
 Like

in the Sun
Nuclear Fission

Splitting the nuclei of large atoms
 Like
in Nuclear reactors
Bonding

Atoms bond in order to fill their valence
shell (outer energy level)

Octet Rule
The idea that most atoms want 8 electrons
in their outer shell and will share, steal, or
give away electrons in order to fill the
valence shell
 Exceptions are those who have less than 6
total electrons

Covalent Bonding
Valence electrons (outer shell) are shared
 Form molecules
 Single, double or triple bonds are possible

www.school-for-champions.com
Ionic Bonding

Electrons are lost or gained from the outer
shell in order to fulfill the octet rule
www.school-for-champions.com
Hydrogen Bonding

Weak bonds
formed between
molecules that
contain polar
covalent bonds
Bonding animation:
http://trc.ucdavis.edu/biosci10v/bis10v/media/ch02/bond_types.html
www.biology.arizona.edu