Chem Lab #2 Yara

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Molecular Models

Name: Yara Sayegh

Subject: Chemistry

Submitted to: Ms. Lady Maalouf

Date: March 23, 2011

Class: IB-1



Yara Sayegh ; 000829016

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*Purpose/Aim/Objective:

The purpose of this experiment was to make models of molecules, using ball-and-stick

model kits; as well as, to convert three-dimensional molecular models to two-dimensional

molecular drawings.

*Apparatus/Equipment/Materials:

- 1 ball-and-stick model set (6-student group)

*Procedure:

1. A ball-and-stick model set was used to construct models of water (H2O), ammonia (NH3),and methane (CH4) molecules. A sketch of each molecule was made, and shape, bond

angles, and type hybridization were noted.

2. Models of hydrogen sulfide (H2S), carbon tetrachloride (CCl4), dichlorodifluoromethane

(CCl2F2), and ethane (C2H6) were constructed. The molecular formula for each of these

compounds was noted, and a sketch of each molecule was drawn and then named.

3. A model of the substances of the air above a burning candle, which contains nitrogen

gas, carbon dioxide gas, oxygen gas, and soot, were constructed.

4. A model urea (CO(NH2)2) was constructed and its shape was sketched.

5. A model of butane (C4H10) was constructed. The model was then sketched. Later, a

model of a different molecule that has the same molecular formula as butane was

constructed. (Butane was made in two ways (isomers)

6. A model of bromochlorofluoromethane (CHBrClF) was constructed. Then the

compound was sketched. After, an isomer of this compound was constructed.

7. Finally, C6H6 was made into a three-dimensional model with two isomers.




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*Data Collection/Processing/Analysis:

Table 1: Molecular Shapes, Bonding Angles, & Type of Hybridization

Molecule Shape Bond Angles Hybridization

Water

H2O

Bent

104.5o

SP3

Ammonia

NH3

Trigonal Pyramidal

107o

SP3

Methane

CH4

Tetrahedral

109.5o

SP3

Hydrogen Sulfide

H2S

Bent

92o

No Hybridization

Carbon Tetrachloride

CCl4

Tetrahedral

109.5o

SP3




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Dichlorodifluoromethane

CCl2F2

Tetrahedral

109.5o

SP3

Ethane

C2H6

Tetrahedral

109.5o

SP3

Nitrogen Gas

N2

Linear

180o

SP

Carbon Dioxide Gas

CO2

Linear

180o

SP

Oxygen Gas

O2

Linear

180o

SP




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Table 2: Molecular Shapes and Structures

Molecule Shape

CO(NH2)2

C4H10

CHBrClF

C6H6

(isomer 1)




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C6H6

(isomer 2)

*Conclusion:

In conclusion, this experiment allowed us to visualize the different molecules in a three-

dimensional perspective. Moreover, it allowed us to further our knowledge of molecules

and their bonding angles and shapes, as well as developed our skill in reproducing the

three-dimensional molecular structures into two-dimensional ones on paper.

*Evaluation & Improvements:

In general, the experiment was nearly perfect. The three-dimensional shapes gave an

almost exact form of the molecules, and their bonding angles were roughly correct.However, a more accurate ball-and-stick model set could have been used to improve the

experiment. A more accurate set would portray the bonding angles more precisely, as well

as the shapes.

Chem Lab #2 Yara

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