Experiment 1 : GEOMETRY SHAPES OF COVALENT MOLECULES

Course Code : CHM 138

Name : Muhammad Hafizzudin Bin Norazahar Matrix No : 2014837388

Name of Lab Partner : Ahmad Harith Bin Amiruddin (2014206332) Date of experiment : 16 July 2014

Lecturess Name : Dr. Rohaiza Binti Saat

Title : Geometry Shapes of Covalent Molecules Objective : 1) To build a geometric structures of simple covalent molecules.Procedure: 1) The geometric shape of the molecules : Beryllium chloride, BeCl2, Boron trichloride, BCl3 , Carbon dioxide, CO2 , Sulphur dioxide, SO2, Carbon tetrachloride, CCL4, Methane, CH4, Ammonia, NH3, Water, H2O.Results : a) Beryllium chloride, BeCl2

ClCClBebe

Geometric shape = Linear

b) Boron trichloride, BCl3

Cl

B

ClCl

Geometric shape : Trigonal planar

c) Carbon dioxide. CO2 OOC

Geometric shape : Linear

d) Sulphur dioxide, SO2 S

OO

Geometric shape : V-shaped

e) Carbon tetrachloride, CCl4Cl

ClClC

Cl

Geometric shape : Tetrahedral

f) Methane, CH4

HHHHC

Geometric shape : Tetrahedral

g) Ammonia NH3 N

HHH

Geometric shape : Trigonal Pyramidal

h) Water, H2O OHH

Geometric shape: V-Shaped

Questions.

1) List down the molecules have lone pair electrons. SO2, NH3, H2O 2) Write the Lewis structures and predict the molecular geometry by using VSEPR method for the following species.

a. H2Se H Se HMolecular Geometry : V-shaped

b. H3O+ + H O H H

Molecular Geometry : Trigonal Pyramidal

References: 1) Laboratory Manual Basic Chemistry CHM138 provided by Madam Nurul Huda Abdul Halim, UITM Kuala Pilah. 2) College Matriculation Chemistry SK016, S.A.P Publication Sdn.Bhd 3) Chemistry Reference Book edited by Raymond Chang. 4) Wikipedia Webpage. www.wikipedia.com/molecular geometry

DISCUSSION:Based on the results obtained, my laboratory partners and I managed to obtain the particular geometry shapes of the specified covalent molecules. In addition, a theory is known as Valance Shell Electron Pair Repulsion theory (VSEPR) is used to predict the shape for covalent molecules and polyatomic ions. There are 3 basic molecular shape that we identified from the results where the central atom has bonding pairs electrons such as linear, trigonal planar and tetrahedral compared with theory that states 5 basic molecular shape which are linear, trigonal planar, tetrahedral, trigonal bipyramidal and octahedral. The molecule that has bonding pair and lone pair electrons such as SO2, H2O and NH3. This experiment could be more successful if we read and understand the instruction manuals first before starting the experiment.

CONCLUSION:The molecular shape and bond angle is affected by the number of lone pairs and bond pairs in the molecules; hence the shape matches our expectation. Thus, the experiment is a success.