Objectives:
- To build 3D ball and stick models of molecules and their structural isomers using an online simulator to get a visual understanding of a molecule’s atoms and how bonding affects structure.
- To build 3D ball and stick models of molecules with different functional groups using an online simulator to get a visual understanding of how atoms are bonded within each functional group.
- To understand what a chiral molecule is and how stereoisomers and enantiomers are formed
Atom Color Key:
Gray – Carbon
White – Hydrogen
Red – Oxygen
Blue – Nitrogen
Green – Halogen (e.g. Cl, F, Br, I)
Procedure:
Open the link https://chemagic.org/molecules/amini.html to find the simulation for this lab. Click on “The Virtual Model Kit (Molecula)” to load the correct module.
- Build a butane molecule. The molecular formula of butane is C4H10. On the left side of the module click on “Draw” under the Load Models section.
A new window will open. Using the single bond button, construct a butane molecule in its skeletal form. The click the “Load Model” button at the bottom of the screen.
This will covert your molecule to a 3D Ball and Stick image.
Draw the structural formula of your butane molecule below. (Recall the structural formula shows the arrangement of atoms in the molecule as well as each bond represented by a line.)
- Are there any isomers of butane that you can build? Draw all the possible different isomers in the space below.
- CH3CH2CH2CH3 and CH3CHCH3CH3 are the condensed structural formulas for isomers of butane. Write the appropriate condensed structural formula by each of your drawings in #2.
- In your own words, what is an isomer?
- Butene has molecular formula C4H8, and contains one ______ bond. Draw all four of butene’s structural isomers below.
- Hydrocarbons with double bonds can have special geometric isomers called “cis” and “trans” isomers. In a cis isomer, the hydrogen atoms that are attached to carbons on a double bond in the interior of the molecule are on the same side of the molecule. In a trans isomer, the hydrogens are on opposite sides. Label the isomers you drew in #5 as “cis” or “trans”. Alkenes with double bonds at the ______ do not have cis or trans geometry.
- Butyne, C4H6, contains one ___ bond. Draw structural formulas for all possible isomers below. Hint: there are two.
- Circle the functional group in each molecule below and label it with one of the following names: alcohol, ether, aldehyde, ketone, carboxylic acid, ester, or amine. Hint: there is only one in each molecule.
a)
b)
c)
d)
e)
f)
g)
- Other functional groups you must know are: aldehydes, ketones, carboxylic acids, esters, and amines. Build each of the molecules below, draw its structural formula, and circle the functional group. Look at the table of functional groups in the reference section at the front of your lab manual or in Table 4.4 starting on page 139 of your textbook, if needed.
a) aldehyde: CH3COH with the O double bonded to the carbon
b) ketone: CH3COCH3 with the O double bonded to the carbon in the middle
c) carboxylic acid: CH3COOH one O is double bonded to the end carbon. On the same carbon, the other O is between that carbon and a hydrogen
d) ester: CH3COOCH3 one O is double bonded to the interior carbon and the other O is between the two carbons
e) amine: CH3CH2NH2
Chiral Molecules: chiral molecules contain a carbon with _ single bonds and _ different groups bonded to it. Circle the chiral carbon(s) in the structures below: Note: a molecule can have more than one chiral carbon
a. b.
c. d. 
