ORGANIC CHEMISTRY BASICS



ORGANIC CHEMISTRY BASICS

OVERVIEW

❑ Organic Chemistry:

❑ Since it has been demonstrated that organic compounds can be synthesized in laboratories we now just say that Organic chemistry is:

o Examples:

❑

❑

Some Examples:

What is the Deal with petroleum and how does it fit into the organic chemisty scheme?

❑ PETROLEUM … Black Gold … Texas Tea

o

o

o Hydrocarbons :

HOW DO YOU KNOW HOW C’s and H’s WILL GET TOGETHER TO FORM HYDROCARBONS?

❑ The Octet Rule

❑ We write Lewis Dot Structures to show the sharing of electrons, and thus formation of bonds between atoms in Covalent compounds

o

o

o

❑ When Carbon shares electrons to fulfill it’s outer shell – it needs to share with other atoms to get 4 more electrons – so it needs to make 4 bonds

o

o

o

o

❑ Example of Lewis Dot structure for C and for H

❑ A shared pair of electrons between 2 atoms is: ________ and the 2 dots representing the bond can be replaced by a line connecting the atoms – this is called a: _______________________

❑ Can also write ______________________that do not show the individual bonds

o Expanded Molecular Formula:

• 2, propanol =

o Condensed Molecular Formula:

• 2, propanol =

ASSIGNMENT: PRACTICE WRITING LEWIS DOT STRUCTURES, STRUCTURAL FORMULAS, AND MOLECULAR FORMULAS

Name__________________

Date________ Period______

1. Draw Lewis Dot Structures for the following elements:

Oxygen Silicon Carbon

Nitrogen Sulfur Phosphorus

2. Given the Expanded molecular formulas, first create 3-D molecular models of the alkanes below. Then draw the correct structural formulas.

CH3CH2CH3 CH3CH3

CH3OH CH3CH2CH2CHCH3CH3

3. Use 3-D molecular models to create a reasonable structure from the condensed molecular formulas below. Draw a structural formula once you are satisfied that your models are reasonable, taking into account how many bonds each element makes.

C4H10 C6H14

4. Compare the structural formulas you drew for the molecules in Question 3 with another lab group. Did everyone come up with the same structure? If not, who is correct?

5. Try to arrange the atoms in the molecule C7H14 in different ways, while still keeping all of the atoms happy. Draw as many DIFFERENT structural formulas as you can below.

Classes of ORGANIC COMPOUNDS

❑ HYDROCARBONS:

o Alkanes –

• Propane =

o Alkenes –

• Propene =

o ALKYNES –

• Propyne =

NAMING HYDROCARBON CHAINS

3 Use “IUPAC” ( ) prefixes to tell number of carbons in longest chain

4 Add ending to tell the type of hydrocarbon (ane, ene, or yne)

|Number of Carbon atoms |Prefix |

| |Meth |

| |Eth |

| |Prop |

| |But |

| |Pent |

| |Hex |

| |Hept |

| |Oct |

| |Non |

| |Dec |

Structural Formulas and Naming of Alkanes and Isomers Lab

Name ____________________

Date_________ Period_______

OBJECTIVE: To be able to assemble models of several simple hydrocarbons and relate the 3-D shapes of molecules to their names and structural formulas used to represent them on paper.

PART 1 – STRAIGHT CHAIN ALKANES

PROCEDURE:

1. Assemble a 3-D molecular model of methane (CH4) and draw the corresponding structural formula in Chart 1 on back of paper.

2. Repeat this process by adding one more C atom in place of a H in the methane molecule and adding enough H atoms to complete the 2 carbon molecule. Repeat this for the compounds with 3 – 10 Carbon atoms, keeping in mind the number of bonds that C and H need.

3. When you have successfully created and written structures for all of the alkanes listed in the chart, go back and find the correct prefix for the number of carbons and list them in the chart.

4. Now go back and correctly name each of the alkanes.

5. Finally, provide the condensed molecular formula for each alkane in the space provided in the chart.

PART 2 – Branched Chain Alkanes - A.K.A. Isomers

1. Assemble a 3-D molecular model with the molecular formula C4H10.

2. Create as many different arrangements of the atoms in C4H10 as you possible can, and draw the structural formulas below.

3. Check with your teacher to determine if you have the identified the correct number of ISOMERS – compounds with the same molecular formula, but different structural formulas (ways that the atoms are put together)

4. Now try to make as many different isomers of hexane (C6H14) as possible and draw the structural formulas below.

CHART 1

|Number of Carbon |Prefix |Name of Alkane |Molecular formula (condensed) |Structural formula |

|atoms | | | | |

|1 | | | | |

|2 | | | | |

|3 | | | | |

|4 | | | | |

|5 | | | | |

|6 | | | | |

|7 | | | | |

|8 | | | | |

|9 | | | | |

|10 | | | | |

QUESTIONS

1. What is the trend in the ratio of C to H in the molecular formulas from Chart 1?

2. Write the molecular formula for an alkane containing 25 Carbon atoms.

3. Did you decide to write the condensed or expanded molecular formula for the previous question? Why?

4. As the number of carbons in a chain increases, what seems to happen to the number of ISOMERS that can be made for the same molecular formula?

5. Would you expect all of the different ISOMERS of a compound like hexane to have the same physical and chemical properties?

CARBON CHAIN LENGTHS

HOW DO WE GET ALL OF THESE DIFFERENT PRODUCTS FROM THAT THICK BLACK SLUDGE?

❑

WHAT ARE THE DIFFERENT CARBON CHAIN LENGTH FRACTIONS USED FOR?

ASSIGNMENT: You Decide pg. 173 – Uses of Fractions

HOW IS THE LENGTH OF THE CARBON BACKBONE CHAIN RELATED TO BOILING POINT?

❑ INTERMOLECULAR FORCES are attractions between molecules of a particular substance (how much molecules of methane “like” each other for example)

o Can be determined by the normal physical state of the substance (solid, liquid, gas)

|Number of Carbon |Prefix |Molecular formula |Name of Alkane |Melting Point |Boiling Point |

|atoms | | | |(C() |(C() |

|1 |Meth |CH4 |methane |-182 |-161 |

|2 |Eth |C2H6 |ethane |-172 |-88 |

|3 |Prop |C3H8 |propane |-187.7 |-42.1 |

|4 |But |C4H10 |butane |-138.4 |-0.5 |

|5 |Pent |C5H12 |pentane |-129.7 |36.1 |

|6 |Hex |C6H14 |hexane |-95 |69 |

|7 |Hept |C7H16 |heptane |-90.6 |98.4 |

|8 |Oct |C8H18 |octane |-56.8 |125.7 |

|9 |Non |C9H20 |nonane |-51 |150.8 |

|10 |Dec |C10H22 |decane |-29.7 |174.1 |

ASSIGNMENT: Your Turn pg. 132 – Alkane Boiling Point Trends

ASSIGNMENT: Your Turn pg. 184 – Alkane Boiling Points: Isomers

PETROLEUM AS AN ENERGY SOURCE

❑ Carbon bonds contain potential energy (actually all bonds contain energy) – the beauty of petroleum is that the long chains of carbons connected to one another contain a lot of bonds – and therefore a lot of potential energy

❑ Petroleum is used for:

❑

❑

❑

o

o

o

❑ A quote from our nutty Russian friend Mendeleev regarding using petroleum as an energy source: he said it would “be akin to firing up a kitchen stove with a bank note”

WHAT ARE THE POLITICAL RAMIFICATIONS OF BEING A SOCIETY THAT IS SO DEPENDENT ON PETROLEUM AS AN ENERGY SOURCE?

❑ 60% of all the petroleum in the world is in 5 countries:

❑ The U.S. petroleum reserves from Prudhoe Bay in Alaska would be enough to supply our energy needs for:

❑ Petroleum cost is determined by:

❑

❑

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download