Transcript Unit 3.A. Powerpoint

Unit 3
Do Now
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READ pp. 210-211
(Some claims made may not be valid)
Answer the following questions:
What do you like about the commercial
What do you not like about the commercial
What would your commercial look like?
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1. SWBAT answer short answer and multiple
choice questions on 2.D.
2. SWBAT identify the objectives and
requirements for the unit 3 project.
3. SWBAT identify petroleum based projects
and hypothesize what life would be like
without petroleum.
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You will learn about:
Molecules that make up petroleum
Uses as fuels & product building blocks
Learning will help you analyze the claims
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Teams will design & present advertisements
featuring an imaginary, but plausible, vehicle
that uses a particular type of fuel
Biodiesel
Compressed natural gas
Hybrid gasoline-electric
Hydrogen-oxygen fuel cell
Other
A. Petroleum: What is It?
 Refining of & uses for petroleum
 Electrons & covalent bonding in
hydr0carbons
 Representations of & formula for
hydrocarbons
 Intermolecular forces & properties of
hydrocarbons
pp. 212-236
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What is petroleum?
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What material is it mined from?
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What two elements is petroleum made from?
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1. SWBAT describe the chemical makeup of
petroleum and how its refined.2. SWBAT
describe and give examples of uses for
petroleum.3. SWBAT explain hydrocarbon
combustion reaction.4. SWBAT apply the
location of petroleum to business, politics,
and economy.
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Let’s make a list of the following items on the
teacher’s desk:
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1. SWBAT describe the chemical makeup of
petroleum and how its refined.
2. SWBAT describe and give examples of uses
for petroleum.
3. SWBAT explain hydrocarbon combustion
reaction.
4. SWBAT apply the location of petroleum to
business, politics, and economy.
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Let’s make a list of the following items on the
teacher’s desk:
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Script for car ad highlighted energy & fuelrelated features that claimed to “help
conserve petroleum resources”
What properties make petroleum useful for
burning & building?
Focus on key compounds in petroleum
Their physical properties, molecular
structure, & how atoms bond to make these
key compounds
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Crude oil – petroleum pumped from
underground
Mixture of many compounds
Colorless to greenish-brown to black
Fluid as water or as resistant to flow as soft
tar. Crude oil is not useable
Must be refined – separated into simpler
mixtures
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Some mixtures are ready to use
Others require more refining
Refined petroleum is mainly a mixture of
hydrocarbons, molecular compounds that
contain only atoms of hydrogen (H) and
carbon (C)
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Most petroleum is used as a fuel (89%)
Burning petroleum provides nearly ½ of the
total U.S. energy needs
Gasoline powers millions of U.S. automobiles,
each traveling 14,000 miles per year
Other petroleum based fuels heat homes &
office buildings, deliver energy to generate
electricity, & power diesel engines & jet
aircraft
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1. What percent of petroleum is used for fuel?
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2. What two elements is petroleum made
from?
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3. List two products that are made from
petroleum.
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4. What is petroleum mined from?
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Petroleum is also a raw material for many
familiar & useful products
 New substances (e.g., medications & plastics)
(7%)
 Other products (e.g., lubricants, road-paving tar)
(4%)
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Nonrenewable resource
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What happens to the molecules contained in
petroleum when they are burned or used in
manufacturing?
The atoms in them rearrange to form new
molecules – as they do in all chemical
reactions
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When hydrocarbons burn, the react with
oxygen in the air to produce carbon dioxide
and water – and, of course, energy
CxHx + O2  CO2 + H2O + energy
Methane burning
CH4 + 2O2  CO2 + 2H2O + energy
Ethane burning
C2H6 + 7O2  4CO2 + 6H2O + energy
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Petroleum is not uniformly distributed
around the world
 66% Middle Eastern Nations
 5% North America
 4% Central Asia, Far East, Oceana
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Figure 3.4, p. 214 – more details
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Answer the questions on worksheet 3.A.1.
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We will discuss answers as a class.
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How would the following might affect the
long-term regional petroleum availability,
use, and trade:
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1. Industrialization/modernization of second
and third world nations
2. Political unrest in the Middle East
3. Population growth in China and India
4. Depilation of Alaskan oil reserves
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1. Which area of the world contains the most
petroleum?
2. What area of the world uses the most
petroleum?
3. What product of burning fossil fuels is a
danger to our environment?
4. What is the goal of the combustion
reaction?
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1. SWBAT explain fractional distillation.
2. SWBAT draw and label a fractional
distillation tower by temperature,
intermolecular forces, and number of
hydrocarbons.
3. SWBAT describe the relationship between
alkanes and their boiling points.
pp. 215-218 – Investigating Matter
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Separation of liquid substances based on
their different boiling points
Distillate:
 Condensed liquid collected
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Crude oil is a mixture of many compounds
It takes more than simple distillation to
separate them
Refining process separates the crude oil
mixture into several smaller mixtures, called
fractions
This process is called fractional distillation
Compounds in each fraction have a particular
range of boiling points & specific uses
Refining Crude Oil
These
fractionating
towers contain
many different
levels of
condensers to
cool the oil vapor
as it rises.
Temperatures
range from about
400oC (at the
base) to 40oC (at
the top).
Crude oil is heated to about
400oC in a furnace
 Pumped into the base of a
distilling column
(fractionating tower), which
is usually more than 100 ft
(30 m) tall
 Many components of the
heated crude oil vaporize
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Temperature of the
distilling column is highest
at the bottom
 Temperature drops towards
the top
 Trays arranged at
appropriate heights inside
the column collect the
various condensed fractions
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Smaller, lighter molecules –
lowest boiling points –
either condense high in the
column or are drawn off the
top of the tower as gases
Fractions with larger
molecules & higher boiling
points are more difficult to
separate
 Require more heat energy
to vaporize
 Condense back into a liquid
in trays lower in the column
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Substances with the
highest boiling points never
vaporize
 Thick (viscous) liquids,
called bottoms, drain from
the column’s base
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pp. 219-220
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1. Petroleum’s gaseous fraction
 compounds with low boiling points (less than
40oC)
 small hydrocarbon molecules: 1-4 carbons
 Low intermolecular forces (forces of attraction)
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LESS INTERMOLECULAR FORCES: Easily
separate & rise
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2. Petroleum’s liquid fraction – varied
 boiling points (less than 40oC – 370oC)
 5-20 carbons
 higher intermolecular forces
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3. Petroleum’s greasy fraction – viscous
bottoms
 boiling points (over 370oC)
 Over 20 carbons
 highest intermolecular forces
 Solids at room temperature
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Draw a fractioning tower:
Label the following:
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Gasoline
Gases
High temperature/Low temperature
Viscous substances
Crude oil
Heat source
Short hydrocarbons/ Long hydrocarbons
Strong intermolecular forces/Weak intermolecular
forces
p. 220, Developing Skills
LAB!
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Label the following picture:
 Diesel
 Gasoline
 Heat Source
 Residue
 Crude Oil
 Gas
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1. SWBAT review fractional distillation.
2. SWBAT define covalent bonding.
3. SWBAT draw Lewis dot structures for
several elements.
pp. 220-224
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Organic Chemistry – focuses on
hydrocarbons & substances that are made
from them
Called “organic”, because early chemists that
living systems were needed to produce
hydrocarbons
Not so – for 150 years - reactants other than
petroleum have been used to make “organic”
compounds
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Hydrocarbon molecules
Carbon atoms join to make a carbon chain
backbone
Hydrogen atoms are attached to the carbon
chain backbone
Carbon’s ability to bond the way it does
explains the abundance of different
hydrocarbon compounds
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What holds atoms together?
Answer is related to the arrangement of
electrons in atoms.
Atoms
 Nucleus
 Protons
 Neutrons
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Shells (Energy Levels)
 Electrons
 Each shell can hold a
specific maximum
number of electrons
Refer to Periodic Table
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H
1e- in 1st shell
He
2e- in 1st shell
1st shell only holds 2e-, so new shell starts
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Li
3e- - 2 in 1st shell, 1 in 2nd shell
Be
4e- - 2 in 1st shell, 2 in 2nd shell
B
5e- - 2 in 1st shell, 3 in 2nd shell
C
6e- - 2 in 1st shell, 4 in 2nd shell
N
7e- - 2 in 1st shell, 5 in 2nd shell
O
8e- - 2 in 1st shell, 6 in 2nd shell
F
9e- - 2 in 1st shell, 7 in 2nd shell
Ne
10e- - 2 in 1st shell, 8 in 2nd shell
2nd shell only holds 8e-, so new shell starts
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Atoms whose last (outer) shell is filled are
unreactive
Found on the right side of the Periodic Table –
Group 18
They all have 8 e- in the outer shell (except for
He, because the 1st shell can only hold 2e-)
Called the “noble gases” or “inert gases”
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Atoms in Group 17 are very reactive
They tend to gain 1e- to finish the shell
Example: F + 1e-  F1- (8e- in outer shell)
Atoms in Group 1 are very reactive
They tend to lose 1e-. In the process, they
lose the entire outer shell. The shell that is
now exposed is filled, or finished.
Example: Na  Na1+ + 1e- (8e- in outer shell)
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Compounds made of nonmetals achieve filled
outer shells by sharing electrons
Covalent bonding
H has 1e- in a shell that can hold 2e-. So, it is
“missing” 1eIf two H atoms come together, they can each
share the 1e- they have. Each H has the use
of its e- as well as the use of the e- from the
other H.
H
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+
H

H:H
Single covalent bond – 1 shared pair of e-
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C atom has 6e-, 2 in the 1st shell & 4 in the 2nd
2nd shell needs 4 more e- to have a total of 8eMethane, CH4, is the simplest hydrocarbon
What would the “dot” equation look like?
4 single bonds
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Structures showing the valence e- as dots are
called:
 Electron-dot formulas
 Lewis dot structures
 Lewis structures
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For convenience, each e- pair can be written
as a dash. These kind of representations are
called a structural formulas.
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These are all 2-dimensional representations
of molecules
3-dimensional models give a more accurate
representation
Help predict a molecule’s physical & chemical
behavior
In 3A.7, you will build models of alkanes
Each carbon in an alkane forms 4 single
covalent bonds with other atoms
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Draw the Lewis Dot Structure for:
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1. C
2. H
3. N
4. Br
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1. SWBAT define covalent bonding.
2. SWBAT draw Lewis dot structures for
several elements.
3. SWBAT draw the Lewis dot structure and
structural formula for several different
molecules.
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Rule 1: Add together the number of valence
electrons for each atom.
Rule 2: Write out the elements without their
electrons.
Rule 3: Add electrons around the elements.
Rule 4: Check to make sure EACH element
has a filled valence shell.
Rule 5: Count the number of electrons around
each element and compare it to step 1. They
should have the same number.
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1. C2H6
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DO NOW
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Draw the lewis dot and structural formula for
propanol.
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C3H7OH
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1. SWBAT build and describe ball and stick
models of isomers.
2. SWBAT differentiate among straight
carbon, branched carbon, and ring structures.
3. SWBAT determine the IUPAC name for
alkanes and draw out molecules.
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Alkanes: hydrocarbons with single bonds
Alkenes: hydrocarbons with one or more
double bonds
Alkynes: carbons with one or more triple
bond
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Straight-Chain Alkanes:
 Carbons in a straight line
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Branched-Chain Alkanes:
 One carbons can be linked to 3 or 4 other carbons
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Ring Structure Alkanes
 Form a circle of carbons
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Structural Isomer:
 Molecules that have the same molecular formula
but different arrangements of atoms.
Structural Isomers of Propanol
Meth
Eth
Prop
But
Pent
Hex
Hept
Oct
Non
Dec
1
2
3
4
5
6
7
8
9
10
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Worksheet Supplement 3.A.9
pp. 224-228, Investigating Matter
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1. CH3-CH2-CH2-CH2-CH3
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2. CH3-CH-CH2-CH
I
CH3
3.
4.
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1. SWBAT graph alkanes and determine the
best fit line through the data.
2. SWBAT answer questions analyzing the
data points.
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Tetrahedron:
 3D shape similar to a pyramid
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Condensed Formula:
 CH3-CH2-CH2-CH3
 Write out all the carbons
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Molecular Formula:
 C4H10
 CnH(n+2)
 Each type of atom is written only once
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Turn to page 228.
Graph the data on page 226
Answer questions #1-3 on page 229
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What did you notice about the number of
carbons and boiling points of alkanes?
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Why do you think this happens?
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1. SWBAT draw models of isomers.
2. SWBAT draw a conclusion about branched
vs. straight chain isomers and boiling points.
3. SWBAT hypothesize about how climate
affects molecules in different fuels.
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Drawing structural isomers
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Draw 2 isomers of butane:
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Try to come up with an many as possible
structural isomers for hexane.
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Turn to page 231 and with a partner answer
questions #1-3
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http://www.whfreeman.com/ChemCom/
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The more branches the LOWER the boiling
point.
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WHY?
The more compact, spherical shape of the
branched isomer affords fewer contacts.
(Easier to separate).
Less Surface Area
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Pg. 235 #29-31, 33, 34, 37, 38
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Draw the lewis dot structure and structural
formula for the following molecules:
1. CF4
2. H2O
3. NH3
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1. SWBAT answer multiple choice and
matching questions in a jeopardy game to
review for their test on Thursday.
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Using the worksheet, list:
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1. your name
2. 2 things your understand
3. 2 things you want to review next class.
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1. The yne suffix (ending) indicates an alkyne
or ene suffix indicates an alkene.
 2. Select the longest chain containing the
double or triple bond.
3. Number from the end nearest the double
or triple bond.
 4. Specify where the bond
starts.
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EX.
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1.
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2. CH3-CH=CH-CH3
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3. CH3-C CH
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CH3-C C-CH3