Chapter 11: Polymers

Section 11.1—Hydrocarbons

Organic Molecules & Hydrocarbons

Organic Molecules – Contain carbon atoms bonded to other carbon atoms

Hydrocarbons – Molecules composed of carbon and hydrogen only

All carbon atoms need 4 bonds to be stable. They can be any combination of single, double, or triple. Hydrogen is used to fill in the remaining bonds!

To understand Polymers – we MUST understand Organic Chemistry!!

Properties of hydrocarbons

Non-polar molecules-Non-soluble in water

Only IMF is London Dispersion Forces

The LARGER the hydrocarbon, the higher the IMF’s! So higher melting and boiling points too!

Trends in Carbon Chain IMF’s!

Alkanes

Alkanes – Hydrocarbons containing only single bonds

Naming Alkanes

Count the longest continuous chain of carbon atoms.

Use the count as the prefix (see table)

Use “-ane” as the suffixTIP – Mom Eats Peanut

Butter…..Meth-, Eth-, Prop-, But- for the order!

TABLE 11-1—ORGANIC PREFIXES

NUMBER OF CARBON ATOMS IN LONGEST

CHAIN

PREFIX

1 Meth-

2 Eth-

3 Prop-

4 But-

5 Pent-

6 Hex-

7 Hept-

8 Oct-

9 Non-

10 Dec-

Example #1

Example:Name the following

molecule

Example #1

Example:Name the following

molecule

Find the longest chain of carbon atoms 4

A chain of 4 carbons = but-

All single bonds = -ane butane

Let’s Practice #1

Draw a molecule of hexane

Let’s Practice #1

Draw a molecule of hexane

Hex- = 6 carbons in a chain

-ane = all single bonds

Fill in with hydrogen atoms to give each carbon atom 4 bonds

Alkenes

Alkenes – Hydrocarbons containing a double bond

Naming Alkenes

Count the longest chain of carbons starting with the end closest to the double bond. Use the carbon that gives the lowest count for the double bond.

Choose the appropriate prefix for this countCount which carbon the double bond is on—

This number goes in front of the prefix and is separated with hyphen

Use the suffix “-ene”

Example #2

Example:Name the following

molecule

Example #2

Example:Name the following

molecule

Find the longest chain of carbon atoms

A chain of 4 carbons = but-

4

Example #2

Example:Name the following

molecule

Find the longest chain of carbon atoms

A chain of 4 carbons = but-

Count where double bond is from the side closest to it

2-butene

In this case, when you count from either side, the double bond begins on the 2nd carbon, so it doesn’t matter what side you count from

4

A double bond = -ene

2nd carbon

2nd carbon

Let’s Practice #2

Name the following molecule

Let’s Practice #2

Name the following molecule

Find the longest chain of carbon atoms

A chain of 7 carbons = hept-

7

Let’s Practice #2

Name the following molecule

Count where double bond is from the side closest to it

3-heptene

From right, it’s on the 4th carbon. From left, it’s on the 3rd carbon. Pick the lower number

A double bond = -ene

4th carbon

3rd carbon

Find the longest chain of carbon atoms

A chain of 7 carbons = hept-

7

Alkynes

Alkynes – Hydrocarbons containing a triple bond

All these NAMES! Here’s a Tip!• Single = ane• Double = ene• Triple = yne • A-E-Y notice that it is in alphabetical order!

Naming Alkynes

Count the longest chain of carbons starting with the end closest to the triple bond. Use the carbon that gives the lowest count for the triple bond.

Choose the appropriate prefix for this countCount which carbon the triple bond is on—

This number goes in front of the prefix and is separated with hyphen

Use the suffix “-yne”

Let’s Practice #3

Draw a molecule of 1-butyne

Let’s Practice #3

Draw a molecule of 1-butyne

1 = triple bond begins on the first carbon

Fill in with hydrogen atoms so that each carbon has 4 bonds

But- = 4 carbons

-yne = triple bond

Isomers

Isomers – Molecules with the same chemical formula, but a different molecular structure

Often, alkenes and alkynes can be isomers of each other.

Both of these have the formula C3H4 but have different structures, as described by their different names.

1, 2—Propadiene 1-Propyne

Saturation

Saturated hydrocarbon – All single bonds—the molecule is “saturated” with as many hydrogen atoms as it can hold

Saturated molecules can pack together tighter and form more intermolecular connections.

Saturated molecules therefore have higher melting and boiling points

SaturatedUnsaturated

Hydrocarbon Side-branches

Hydrocarbon side-branches – Some molecules have groups of hydrocarbons branching off the main chain of carbons.

Naming hydrocarbon side-branches

Count the longest chain of carbon atoms (even if it’s not in a straight line) and choose the appropriate prefix for the chain.

Count to the carbon that the side-branch is on. Always count in a direction that gives the lowest number to the branch! This count will become a number in front of a prefix that represents the length of the side chain. (See the last slide for names)

Count the length of this side-chain and choose the appropriate prefix for the side chain.

Use an appropriate suffix to end the nameAll together it will be: #-prefix prefix suffix

Example #3

Example:Name the following

molecule

Example #3

Example:Name the following

molecule

Find the longest chain of carbon atoms

A chain of 7 carbons = hept-

7

7 carbons

6 carbons

4 carbons

Example #3

Example:Name the following

molecule

Count where side-chain is from the end closest to it

3-methyl heptane

From the closest end, it’s on carbon #3

A double bond = -ene

Find the longest chain of carbon atoms

A chain of 7 carbons = hept-

7

Side-chain

7 carbons

The side-chain has 1 carbon = meth-

Side Chain Names and –ene and -yne

A side note – when naming double and triple bonds – the double and triple bond ALWAYS gets the lowest number. The side branch DOES NOT get the lowest number count.