Question

Organic Structures Shapes and Isomerism

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Version 42-0183-00-02

Lab Report Assistant

This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Organic Structures Shapes and Isomerism

Data Table 1. The Tetrahedral Carbon Atom.

Question	Answer
How many prongs are found in the model carbon atom?
What do the sticks represent in the model?
How many covalent bonds are necessary for each carbon atom in an organic molecule?
What is the bond angle as represented by any pair of the short sticks?
What causes the bonds to be symmetrically arranged around the carbon atom?

                    

Data Table 2. Alkanes and Alkyl Groups.

Question	Answer
Describe the similarities and differences between the methane and dichloromethane models
What is the formula of an ethyl group?
Drawing of the structural formula of 2 joined methyl groups.
Name of compound created
Molecular geometry of each carbon atom.
Is staggered or eclipsed favored? Explain your answer.
Are all hydrogens equivalent?
Name of the alkyl group
Drawing of the structural formula the alkyl group.
Drawing of the structural formula of the hydrocarbon
Name of hydrocarbon. Are all hydrogens equivalent?

Data Table 3. Isomers.

Question	Answer
Formula of butane
Drawing of the structural formula of butane
Formula of 2-methylpropane
Drawing of the structural formula of 2-methylpropane
Similarities and differences between butane and 2-methylpropane
Names of C5H12 isomers
Names of C3H6Cl2 isomers

INSERT A PICTURE OF YOUR BUTANE ISOMERS.

Data Table 4. Cycloalkanes.

Question	Answer
Bond angles between the carbon atoms of cyclopropane
Is cyclopropane more or less stable than propane? Explain why.
Bond angles between the carbon atoms of cyclobutane
Is cyclopropane more or less stable than cyclobutane? Explain why.
Bond angles between the carbon atoms of cyclohexane in “chair” form.
Is “chair” form more or less stable than “boat” form? Explain why.

Questions

Part A

What is the difference in the number of carbon atoms between methane and ethane and between ethane and propane?

Part B

What is the difference in the number of hydrogen atoms between methane and ethane and between ethane and propane?

Part C

What is the formula for a 6 carbon alkane?

Answer 1

Data table 1.

Question	Answer
How many prongs are found in the model carbon atom?	4
What do the sticks represent in the model?	bonds
How many covalent bonds are necessary for each carbon atom in an organic molecule?	4
What is the bond angle as represented by any pair of the short sticks?	109.5 (twtrahedral)
What causes the bonds to be symmetrically arranged around the carbon atom?

Data Table 2. Alkanes and Alkyl Groups.

Question	Answer
Describe the similarities and differences between the methane and dichloromethane models	Both contains central C atom and both contains 2 H atoms. Dichloromethane contains 2 Cl atoms whereas methane contains additional 2 H atoms. The H and Cl atoms are represented by balls of different colours.
What is the formula of an ethyl group?
Drawing of the structural formula of 2 joined methyl groups.
Name of compound created	Ethane
Molecular geometry of each carbon atom.	Tetrahedral due to hybridization.
Is staggered or eclipsed favored? Explain your answer.	Staggered conformation is favored as steric repulsions are minimized.
Are all hydrogens equivalent?	Yes
Name of the alkyl group	Ethyl group
Drawing of the structural formula the alkyl group.
Drawing of the structural formula of the hydrocarbon
Name of hydrocarbon. Are all hydrogens equivalent?	Ethane. All the hydrogen atoms are equivalent.

Data Table 3. Isomers.

Question	Answer
Formula of butane
Drawing of the structural formula of butane
Formula of 2-methylpropane
Drawing of the structural formula of 2-methylpropane
Similarities and differences between butane and 2-methylpropane	In butane all the four C atoms are in a straight chain. In 2-methyl propane, branching appears.
Names of C5H12 isomers	n pentane, iso pentane, neo pentane, tert pentane.
Names of C3H6Cl2 isomers	1,1-dichloro prpane, 1,2-dichloropropane, 1,3 -dichloropropane and 2,2-dichloropropane.