Elements For Life

1
Elements For Life

• Only 25 Elements Make up Body Chemicals
• H, C, N, O make 99.3 of these
• 0.7 made from other 21 elements
• Carbon the Backbone
• Member of group 4
• a. Must gain or lose 4 e-s
• Electronegativity of 2.5 makes ion not
  possible
• b. shares 4 electrons
• Sharing gives it 8 electrons, like a noble
  gas

2
Carbon Sharing

• C can share in many different ways
• a. with other Cs to make long chains
• b. multiple es to make double and triple bonds
• c. with other elements along the chain
• d. in any direction and any arrangement
•       with 4 Cs in all direction makes
  diamond
• in chains, Cs can be branched to
  sides
•      isomers are made when the same number
  of atoms are
• arranged differently

3
Bonding by Mixing Orbitals

• Cs electron configuration is 1s22s22p2
• orbital notation shows the bonding
  possibilitiesup to 4 bonding orbitals
•      The bonding orbitals mix or hybridize to
  become sp3 orbitals
• d.  Mixing can occur between any number of s, p,
  and even d orbitals for multiple bonds
• i. sp used in triple bonds
• ii. sp2 used in double bonds

4
Organic Chemistry

• Carbons special properties in bonding
• a. long chainsno other element, not even Si
• b. strong bonds with other elements
• c. isometric arrangements
• Over 3 million compounds
• a. only about 500,000 inorganics
• b. inorganics rare with over 12 atoms
• c. organics can have over 1 million atoms per
  molecule

5
Structural Formulas

• Because carbon can make up to four bonds, its
  compounds have various shapes depending on how
  the bonds are made.
• Two ways of designating organic formulas are the
  structural and condensed formulas
• C5H12 in 3 ways

6
Isomers

• 1. Example ? C4H10 C
• CCCC CCC
• Different structures and different properties
• 2. Number of different isomers increases with
  number of carbons
• a. butane (4C) has two
• b. pentane (5C) has three
• c. octane (8C) has eighteen
• d. 40 C would have 60 trillion isomers

7
Give all possible isomers of C7H16
8
Homework

• CYU p 278 all
• p. 307ff 8, 9, 10

9
Hydrocarbons

• Made of only C and H
• Most obtained from petroleum by fractional
  distillation
• i. liquid petroleum is heated
• ii. various hydrocarbons boil at different
  temperatures
• iii. the portions are separated as they
  condense Structural formulas
• a. formula represented by lines for bonds
  between Cs and Hs
• b. Isomers represented by different formulas
• c. formula can be condensed as well to save
  space

10
Saturated HydrocarbonsAlkanes

• Numbering System based on Cs in the Molecule
• Prefixes for carbons
• 1 Meth- 2 Eth- 3 Prop- 4 But-
• 5 Pent-   6 Hex- 7 Hept- 8
  Oct-
• 9 Non- 10 Dec-
• 2. Saturatedonly single bonds between Cs
• 3. Alkanes very stable, least reactive
  hydrocarbons
• 4. International Union of Pure and Applied
  Chemistry standardizes naming

11
Naming Rules for Alkanes

• Count the number of carbons in the longest chain,
  even if the chain bends
• 2. Find all substitutions (atoms or carbon groups
  connected onto the side of the chain) and name
  them
• 3. Number the carbon chain from the end closest
  to the first substitution, halogens get priority
  over carbon groups
• 4. Give a number for each substituent and a
  prefix for more than one of each

12
Alkyl groups

• Used in naming, are alkanes with one H removed,
  where it can bond to something else
• -CH3 methyl -CH2CH3 ethyl
• -CH2CH2CH3 propyl CH3CH2CH3 isopropyl
• - phenyl Many others possible, see
  p282,3

13
Name these alkanes with alkyl groups attached
14
Functional Groups

• The ability of carbon to bond makes it possible
  to bond not only to other carbons, but to other
  elements as well. This makes for the immense
  number of organic compounds carbon can make.
• Part of the reason for so many compounds are the
  functional groups, which will be shown later.

15
IUPAC Naming System of Suffixes

• -ane Alkanes
•  -ol Alcohols (Contains OH group)
• -ene Alkenes (double bonds)
• -one Ketones (contains CO group)
• -yne Alkynes (triple bonds)
• -olic acids Carboxylic acid (-COOH group)

16
Reactions of Alkanes

• 1. Combustionadding oxygen makes CO2 and H20
• C5H12 8 O2? 5 CO2 6 H2O
• 2. Incomplete combustion (not enough O2
  available) makes CO
• 2 CH4 3 O2 ? 2 CO 4 H2O
• a. CO produced is very toxicbinds to
  hemoglobin in blood
• b. Small amount can bind enough Hbg to be fatal
• i. Dr. death Jack Kevorkian uses CO
• ii. Present in tobacco smoke
• 3. Substitution Reactionsexchanging something
  for H
• H3CH HONO2 ? H3CNO2 H2O
• Methane nitric acid nitromethane agua
•  
• H3CH Cl2 ? H3ClCl HCl
• Methane Chlorine chloromethane hydrogen
  chloride

17
Homework 12b

• p. 308ff 13, 14, 15, 16, 17, 18, 21, 23, 24