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Welcome to Chemistry 106

John Keller

http://chem.uaf.edu/keller/Courses/106Sp11/

• Syllabus: Text, clickers,  OWL, grading, help• Course coverage• Fall 2010 Chem 105: How did it turn out?• What do I need to remember Chem 105?• OWL: Chapter 10• Organic Chemistry

www.uaf.edu/chem/faculty/jkeller/

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Syllabus

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Extra help: Find the ones that suit you, and use them early in the semester.

Problem/Review session Tuesdays 8:10-9:10 PM (201 Reic)JK office hour Thursdays 8:10-9:10 PM (161 Reic)OWL tutorials and exercisesChem 106 teaching assistants office hours (ANY) office hours posted on BlackboardChemistry tutors and computers available in 170 ReichardtYour teaching assistant: extra time in lab and office hoursYour text!

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Real-Time Clicker Registration

You may use the OWL applet, or send it to me by email. We will do this again in class Tuesday.

“Serious clicking” will begin Tuesday, Feb. 1, by which time you should have your clicker registered with JK.

lion : pride :: elephant :

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 pack

 fami

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 herd

 broo

d

9

1

24

11

1. pack2. family3. herd4. brood

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Exam 1

Exam 2

Exam 3

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JK’s Chem 105 Fall 2010 Class – How Did It Turn Out? 

Chem 105 ave = 57.5%955 chem students nationwide ave = 55.4%

American Chemical Society Examinations Institute First Term General Chemistry Exam

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ACS Final Exam Results by Question 

The same topics that are hard or easy for YOU, are hard or easy for students NATIONWIDE!

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What do I need to remember from Chem 105?

Significant Figures, Dimensional analysis and Units Names and formulas of ions and ionic compounds Balancing chemical equations Using mole ratios in stoichiometry problems Molarity and using it in dilution problems Ideal gas equation: anytime we discuss P, T and moles of gases. And others…

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2. Chapter 10  ‐ Carbon compounds and organic chemistry

Why is carbon unique? 25,000,000 known organic compounds.Formulas in organic chemistryHydrocarbonsStructural IsomersAlkenesGeometric Isomers

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1)  Compared to other Period‐2 atoms, carbon forms most number of bonds (4) (with formal charge = 0).

Carbon is extremely versatile due to having: 1) four bonds and 2) strong C‐C bond

F

ON

ON

C

C

CB

C

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Classes of organic compounds for Chem 106

Hydrocarbons:            alkane, cycloalkane, alkene, alkyne, aromatic (C,H)

C

H

H

H

CC C CC

CC

C

CC

alkane, cycloalkane, alkene, alkyne, aromatic

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Classes of organic compounds for Chem 106

Oxygen‐containing:   alcohol, ether, ketone, carboxylic acid  (C,H,O)

O

H

H

H

H

H

H

OH

H

HO

H

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Chemical formulas vary in information content

Molecular formula is just a LIST of atoms present  C3H6OExample: Acetone (the common solvent)

Condensed formula lists groups of bonded atoms present  CH3COCH3

Structural formula (or Lewis structure) shows all bonds and (usually) lone pair electrons.  C

HH

HCO

CH

HH

Perspective drawing (or stereochemical structure) shows 3D arrangement of atoms.   Line is in plane of paper (     ), WEDGE is UP (         ).  DASH is DOWN (         ) 

O

H H

HHH H

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Organic chemists often use “skeletal formulas” 

‐ Many “C”s & “H”s are not shown.‐ Each vertex = one C atom‐ # Hs can be added to obey Octet Rule.‐ N, O, F, atoms must be shown explicitly‐ Each = or ≡ bond must be shown

C

CC C

C

CC

HH

H

HH

HH CH3

HH

H

CH2CH2CH

HH

O

H3C

O

H

O

CH3H3C

O

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Hydrocarbons

Alkanes – all sp3 carbons

Alkenes – one (or more) C=C bond (sp2 C)

Alkynes – one (or more) C≡C bond  (sp C)

Cycloalkanes – all sp3 carbons in a ring

CnH2n+2

CnH2n (one ring)

CnH2n (one C=C)

CnH2n‐2 (one C≡C)

NB:  OWL would call a cycloalkane an “alkane” because it contains all sp3 carbons.

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A molecular formula can refer to several different structural isomers.

For example C4H10

Fill in H’s to make 4 bonds to C.    Gives 10 H’s either way.

(C6H14 on the board – 5 isomers.)

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Isomers differ in the way they are put together, or the order in which the atoms are connected. This is the topology of the molecule, rather than its shape.

CC C C C C C

These are NOT isomers: they all have essentially the SAME linear chain of 7 carbon atoms. 

One isomer of C7H16

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Heptane molecular dynamics

HyperChem software using Molecular Mechanics methodComputer, Molecular Dynamics, 1 ps, T = 1300 K

This shows typical behavior of a molecule in the gas phase, which is a combination of many vibrational and rotational motions.

20

CCCC C C C

CCCC C C

C

CCCC C

CCCC C

C C

CCCC C

C C

CCCC C

C

C

CCCC C

C

C

CCCC C C CCCC C C

C

CCCC

C

C

C

CCCC C

C

C

CCCC

9 isomers of heptane

How many isomers of pentane (C5H12) are there?

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 one

 two

 three  four  five  six

4

13

55

10

191. one2. two3. three4. four5. five6. six

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Alkane names are based on length of longest chain Need to know C1 – C10 names.

not obvious –need to learnif you don’t know them

The usual Greek roots