Visualizing Complex Molecules in 3D Lab Assignment Sheet No 13 I need answers to this lab its very easy and simple. 3 molecules are attached. I need to ans

Visualizing Complex Molecules in 3D Lab Assignment Sheet No 13 I need answers to this lab its very easy and simple. 3 molecules are attached. I need to answer the 7 question about each one. Thank you No need for Pre-Lab. I only need the procedure. Visualizing Complex Molecules in 3D
•
•
•
Lab
13
The lab report is due at the end of the laboratory period.
Students must work individually and cannot collaborate during this lab.
Each student will check out a model kit and tray.
OBJECTIVES
– To practice using Lewis structures, VSEPR theory, and molecular models to predict and describe
the three-dimensional shapes of molecules with multiple central atoms.
– To practice drawing projection formulas to depict the three-dimensional structures of complex
molecules.
– To further explore the relationship between molecular geometry, orbital hybridization, and
bonding.
INTRODUCTION
The three-dimensional shape of a molecule plays a crucial role in its interaction with its surroundings,
particularly in living organisms. For example, capsaicin, the primary active component of chili peppers,
causes a strong burning sensation due to its binding to the TRPV1 ion channel receptor in mammals.
Since this receptor is normally used to sense body temperature, the ‘burning’ sensation is actually just
a nerve response to the shape-induced receptor binding of capsaicin, rather than a real chemical burn
caused by the molecule.
Figure 1: Structural formula of capsaicin, the active component of chili peppers
Recall that the overall shape of a molecule is determined largely by the geometry about each of the
central atoms. This geometry is in turn governed by the numbers of bonding and lone electron pairs
around each atom. By determining the Lewis structure for a molecule and applying VSEPR (Valence
Shell Electron Pair Repulsion) theory, it’s possible to predict the molecular geometry and hence the
overall shape of the molecule. Even for larger, more complex molecules, this same approach can be
applied by separately examining each central atom to determine the geometry.
In this lab activity, you will continue to work with ball-and-stick molecular models to explore the
geometry of more complex molecules with multiple centers. For each molecule, you will be given the
chemical formula and a partial structural formula, which shows the connectivity of atoms but lacks the
correct bond orders. You will then draw the correct Lewis structure and, with the aid of your modeling
kit, sketch the 3D projection formula of the molecule. Finally, you will use your model and sketch to
determine the molecular geometry, hybridization, and bond angles at selected central atoms.
Lab 13 – Page 1 of 4
Figure 2: Example Lewis structure (left) and 3D projection formula (right) for aminomethyl propanol
PROCEDURE
You will be assigned by your TA to build three different molecules. For each molecule, complete steps
1-7 below, recording your results in the Data Section of your lab notebook. You should begin a new
page in your lab notebook for each molecule. Note that this is an individual activity— students may not
work together. Use of cell phones or other electronic devices during this lab is not permitted without
TA approval.
Molecular Modeling Activity
Begin a new page in your lab notebook for each molecule. Label each section with the chemical
formula of the molecule and its name (if given). Then complete the following steps:
1. Determine the total number of valence electrons in the molecule.
2. Use the partial structural formula given to draw a Lewis structure for the molecule,
accounting for all of the valence electrons. Be sure to draw the correct bond order (i.e.
single, double, etc.) for each bond in the molecule. If multiple Lewis structures can be
drawn, decide on the most probable correct structure and indicate the chosen structure.
3. Using your chosen Lewis structure and VSEPR theory, construct a ball-and-stick model of
the molecule, choosing the appropriate building block for each central atom based on the
electron group geometry and the number of bonds.
4. Use your model to sketch the 3D projection formula of the molecule in your lab notebook,
including labels for the specified central atoms (1,2,3..) and bond angles (a,b,c..).
5. For each of the numbered central atoms in the molecule, list the following in a table:
i.
Electron group geometry about the specified atom
ii.
Molecular geometry about the specified atom
iii.
Hybridization of the specified atom
6. For each of the specified bond angles, use VSEPR theory to predict the approximate angle.
7. Finally, determine the total number of sigma (?) and pi (?) bonds in the molecule.
Lab 13 – Page 2 of 4
STUDENT ASSIGNMENTS
I. Pre-laboratory Preparation
Prior to attending the laboratory period, complete the following activity in an organized manner in
your laboratory notebook. This assignment is due at the beginning of the lab period.
A. Introductory Statement
Briefly summarize in your own words (not the lab manual’s) the purpose, theory and procedure
for this laboratory activity.
B. Pre-laboratory Activity
Shown below is the partial structural formula for the amino acid L-cysteine, HSCH2(NH2)CHCOOH.
The dotted lines represent connectivity of the atoms, but the structure does not show the
correct bond orders (single, double, etc.). Complete the following activity for L-cysteine.
1. Write the name and chemical formula of the molecule shown above.
2. Determine the total number of valence electrons in the molecule.
3. Use the partial structural formula to draw a Lewis structure for the molecule, accounting
for all of the valence electrons. Be sure to draw the correct bond order (i.e. single, double,
etc.) for each bond in the molecule. If multiple Lewis structures can be drawn, decide on
the most probable correct structure and indicate the chosen structure.
4. Using your chosen Lewis structure and VSEPR theory, sketch the 3D projection formula of
the molecule in your lab notebook, including labels for the specified central atoms
(1,2,3,4) and bond angles (a,b,c,d).
5. For each of the numbered central atoms in the molecule, list the following in a table:
i.
Electron group geometry about the specified atom
ii.
Molecular geometry about the specified atom
iii.
Hybridization of the specified atom
6. For each of the specified bond angles, use VSEPR theory to predict the angle.
7. Finally, determine the total number of sigma (?) and pi (?) bonds in the molecule.
Lab 13 – Page 3 of 4
II. Data
For each of the 3 assigned molecules, record the chemical formula and name (if given), along with the
results from Steps 1-7 in the Molecular Modeling Activity. Organize your work by molecule; begin a new
page of the lab notebook for each molecule. All work should be neat and legible.
III. Calculations
There are no calculations for this lab.
IV. Post-Laboratory Assignment
There are no post-lab questions for this lab.
V. Results and Conclusion
Write a brief summary of what you learned during this lab activity. Briefly discuss your results and any
strengths or limitations of the approach that was used in this lab for predicting molecular structure.
Lab 13 – Page 4 of 4
Molecule assignment sheet- Group B
Lab 13
Use the structures below to complete the Lab 13 molecular modeling activity.
DO NOT WRITE ON THIS SHEET. Return this sheet to the TA before leaving lab.
Structure 1: Urea – OC (NH2)2
H—N—C—N—H
C1
2
a
H
H ?
Structure 2: Propynal – HC2CHO
H
H—C—C——-
Structure 3: Ethyl acetate – CH3COOCH2CH3
??
H H
b
H—C—C—0–
C—C—H
I—0—I
3
H.
H

Purchase answer to see full
attachment