Web Activities
UNIT 2: STRUCTURE AND PROPERTIES
Chapter 4: Chemical Bonding
Section 4.1 General Links
Kekule's
Structural Formulae
This is the third page of an article explaining Kekule's contribution
to developing a system of notation for chemical structures. The article
indicates using his own drawings that what we call Kekule structures
were in fact developed by another scientist named Couper.
p. 233
Practice
Question 7
Research and write a brief report outlining the basic principles
of molecular orbital theory.
Valence
Bond Theory and Hybrid Atomic Orbitals
This University of Waterloo website provides an excellent tutorial in
valence bond theory, and then teaches how to apply this knowledge to
deducing how hybrid atomic orbitals must work. This site includes images
and self-assessment questions.
p. 240
Practice
Question 30
Information about atoms and molecules is often obtained from
the interaction of substances with various forms of electromagnetic
radiation. (Recall the bright-line and dark-line spectra of atoms.)
For molecular substances, the infrared region of the electromagnetic
spectrum is particularly useful for obtaining information about covalent
bonds. Research and write a brief report answering the following questions.
a. What characteristic of the atoms in a molecule is related to infrared
(IR) radiation?
b. How are different covalent bonds distinguished in an IR spectrum?
Why is the analysis useful in studying and identifying molecules?
c. Other than research chemists, who uses this technique?
Basic
Infrared Spectroscopy
As part of a group of websites, entitled, "Organic Chemistry Online,"
this website provides an introduction to using IR Spectroscopy to identify
organic molecules. Also provided are several sample IR spectrums, along
with their analyses.
Section 4.2 Case Study (Benzene)
p. 241
The
Benzene Ring
This interesting website from the Chemistry Department of the University
of Newcastle upon Tyne (in the U.K.) is full of images of benzene that
several scientists proposed might represent the actual structure of
the aromatic ring. It explains the advantages and disadvantages of many
of the proposed models.
Benzene
This website was put together by a teacher to discuss the structures
that are used to describe benzene, and to talk about benzene's actual
structure. It incorporates atomic and molecular bonding theory into
the explanation.
Vibrational
Modes of Benzene
This chemistry website from the University of California, Berkeley contains
3 short animations that demonstrate the different molecule vibrations
that can be used to account for benzene's composition and reactivity.
Section 4.2 General Links
Atomic
Orbital Viewer
This website contains an overview of atomic orbitals with many images
to show representations of their shapes. More importantly, it also has
downloadable software, entitled "Orbital Viewer," which allows
you to generate pictures of atomic orbitals, with many different features
included.
Atoms
and Molecules
This McMaster University website has been prepared by the leading researcher
Richard F.W. Bader, who discusses throughout a very organized group
of websites, theoretical aspects of atoms and their bonding.
Ode
to Hybridized Electron Orbitals
A poem by Eric Tulsky.
The
sp, sp2 and sp3 Hybrid Orbitals
This Purdue University website has pictures of some hybrid orbitals,
but also contains links to explanations regarding bonding theory and
molecular/atomic orbitals.
p. 247
Practice
Question 6
Locate two or more VSPER Web sites and compare them. Which
do you prefer? List two or more criteria for evaluating the sites and
indicate how each site did based on each criterion.
What
is VSEPR?
This Purdue University website systematically explains in a variety
of was how exactly VSEPR theory works. It also provides several examples
of molecules' shapes along with their images.
Valence
Shell Electron Pair Repulsion (VSEPR)
This site is provided by a Chemistry professor at the University of
Sheffield in England. It contains an explanation regarding the bonding
of atoms, and proceeds to demonstrate the structures of several different
atoms. You will need to download free CHIME software in order to access
all of the information on this website.
The
VSEPR Theory of Molecular Geometry
This website belongs to a group of websites, called "ChemTeam,"
that contain tutorials for high school chemistry students. This website
contains a very organized explanation of VSEPR theory with several images.
p. 247
Practice
Question 7
Enzymes make up the largest and most highly specialized class
of protein molecules. Describe briefly how their three-dimensional structure
influences their function. How does the “lock-and-key” analogy
relate to molecular shapes and the highly specific nature of ensiled
reactions?
Thousands
of Locks and Keys
This website connects molecular structure with the physiological function
of certain molecules, like enzymes. It contains several images of molecules,
and discusses their diverse roles in the human body.
Enzymes
This Industry Canada website is part of a "Genetic Engineering
Basics" group of sites. It provides an excellent article explaining
very clearly and accurately what exactly enzymes are, along with what
they do.
p. 247
Practice
Question 8
What are optical isomers? Describe the role that molecular
shape plays in classifying optical isomers.
Geometric
and Optical Isomers
As part of a set of websites entitled, "An Introduction to Chemistry,"
this website explains, using text and images, two different types of
isomers: geometric isomers and optical isomers. It also provides a few
examples of each type of isomer.
p. 250
Explore an Issue
Take a Stand: Linus Pauling and the Vitamin C Controversy
e. The vitamin C controversy is not the first time a famous
scientist has made a claim that is disputed by most of the scientific
community. What are the repercussions for a scientist who goes against
the rest of the scientific community? Who usually “wins”?
Is the practice and work of science completely objective?
Linus
Pauling lectures on Vitamin C
This website article is a government official's report of a 92-year-old
Linus Pauling's speech at a seminar on heart disease. It reports on
his lecture on the connection between Vitamin C and cardiovascular disease.
Vitamin
C
This informative website comes from the Linus Pauling Institute at Oregon
State University. It discusses in good detail various aspects of the
molecule, Vitamin C, including its function, the results of its deficiency,
and some of its benefits in the human body.
The
Vitamin C Foundation
This foundation's website serves as a platform for promoting the use
and benefit of Vitamin C by sharing news and journal items that demonstrate
Vitamin C's efficacy in a variety of health matters. The site contains
several pro-Vitamin C links.
The
Vitamin C Controversy
This article is found on a website belonging to the Life Extension Foundation,
whose members have conducted large scale blood screening tests to determine
the truth about dietary supplements. This article describes a study
showing that high doses of Vitamin C contribute to lower risk of cardiovascular
death.
The
Dark Side of Linus Pauling's Legacy
Written by Stephen Barrett, M.D., this article argues that Linus Pauling
is responsible for spreading mis-information about Vitamin C, especially
with respect to the common cold. The article argues that all large-scale
clinical trials have not found any connection between the mega-doses
of Vitamin C that Pauling recommended and any health benefit.
Vitamin
C: How Much Do You Really Need?
This article, from a popular health and medical website for the public,
explores the different studies that have recently shed light on the
role of Vitamin C in good health. It shares the findings of several
recent studies that have not succeeded in confirming Pauling's recommendations
about Vitamin C.
Section 4.3 Questions
p. 250
Question 5 Search the Internet for information on the current
workplace and position of Dr. Ronald Gillespie, the co-creator of VSPER
theory. What degrees does he hold? What are some of the major awards
he has won? What is his major topic of research?
Ronald
Gillespie: A Lifetime in Chemistry
This article, from the McMaster Chemical Extracts, explains Ronald Gillespie's
role in developing VSEPR theory--a theory that predicts the geometric
shape of molecules.
Ronald
J. Gillespie: Professor Emeritus
This page is Dr. Gillespie's entry in the faculty pages of McMaster
University. In it, Dr. Gillespie describes his research in Molecular
Geometry. The page also contains links to his C.V. and a list of his
numerous publications.
Section 4.3 Questions
p. 250
Question 6
Some scientists argue that taste has developed as a protective
mechanism. Many poisonous molecules taste bitter and ones that are useful
to us have a more pleasant, often, sweet taste. Write a brief summary
about the relation of taste to molecular structure.
Tasting
the Shape of Molecules
This page explains the connection between the shape/type of a molecule,
and the way our body's tongue uses that shape to identify what the molecule
might be. For instance, it describes how tasting can distinguish between
bitter poisons and sweet, nutritious food.
Section 4.3 General Links
Molecular
Models
This site provides all common molecular shapes (shown with and without
electron pairs) as interactive Chime models. The site is provided by
the Chemistry Department at Okanagan University College.
The
Molecule of the Month
Using this website, provided by the Virtual Library group of sites,
you can get the molecular structure of several molecules in many different
formats plus some neat stories about the molecule’s discovery.
p. 264
Practice
Question 15
Wetting agents are very important in agriculture and other
industries. What are wetting agents? Where are they used and for what
purposes? Briefly explain how the function of wetting agents relates
to the principles of intermolecular forces.
Class
A Foam for Fire Control
This excellent article comes from Fire Magazine in Australia. It's very
thorough discussion of the history of water and its fire-fighting capabilities
leads steadily towards the present day, in which Class A foam is used
to fight fires.
New
Surfactants for New Applications
This report discusses the key property of surfactant--an ability to
reduce the surface tension of water and other solvents--and explains
how this property is used in a wide variety of practical applications.
The website actually exists to promote a very detailed report on surfactants
that the company has available for sale.
Surfactants
This company's website has for sale several chemical surfactants with
a variety of compositions and applications.
p. 265
Practice
Question 17
In 1966, Soviet scientists claimed to have discovered a new
form of water, called polywater. They story of polywater is an interesting
example of how people, including scientists, want to believe in a new,
exciting discovery, even if the evidence is incomplete. Write a brief
report about polywater, including how it is supposedly formed, some
of its claimed properties, the explanation in terms of intermolecular
forces, and the final evaluation of the evidence (specifically, the
flaws).
Polywater
and the Role of Skepticism
This excerpt from a report of the National Research Council briefly
explains the emergence of knowledge about polywater, and then the resultant
announcement that in fact polywater did not exist.
Declustered Water, Anomalous Water and Crystals
This site belongs to a group of sites by Mark Chaplin, entitled, "Water
Structure and Behaviour." This site discusses all of the different
forms of water that are purported to exist, including polywater, and
simply explains what kinds of research have been performed on them,
and the results that have been attained.
Section 4.5 Questions
p. 266
Question 11
Some vitamins are water-soluble (e.g., B series and C), while
some are fat soluble (e.g., A, D, E, and K).
a. What can you infer about the polarity of these chemicals?
b. Find and draw the structure of at least one of the water-soluble
and one of the fat-soluble vitamins.
c. When taking vitamins naturally or as supplements, what dietary
requirements are necessary to make sure that the vitamins are used
by the body?
d. More of a vitamin is not necessarily better. Why can you take a
large quantity of vitamin C with no harm (other than the cost), but
an excess of vitamin E can be dangerous?
Vitamin
Wikipedia, the free encyclopedia, is this source of information on vitamins.
Vitamins are broken up into fat-soluble and water-soluble groups. Click
on the name of a vitamin to find out further information on that vitamin,
including its chemical structure.
Vitamin
Deficiencies
This family resource website provides an easy-to-read table describing
all of the body's essential vitamins, and the disorders that might result
from their deficiencies.
Section 4.5 Questions
p. 266
Question 12
Many of the new materials that are being invented for specific
purposes show an understanding of structure and bonding. One candidate
that has been suggested as a future product is commonly known as the
“fuzzyball,” C60F60 (s). What is the structure of this molecule?
What use is proposed for this substance? Explain this use in terms of
intermolecular forces.
Fullerenes
Foment a Feeding Frenzy
This brief essay explores the history of the buckminsterfullerene molecule,
and the understandings of the carbon atom and carbon-containing molecules
that led up to it. It provides pictures of several carbon molecules
as well.
Section 4.5 Questions
p. 267
Question 13
People who wear contact lenses know that there are hard and
soft contact lenses. The polymers used in each type of lens are specifically
chosen for their properties. What is the property that largely determines
whether the lens is a hard or soft lens? Write a brief explanation using
your knowledge of intermolecular forces.
Contact
Lens Polymers
This website from the State University of New York (SUNY) at Buffalo
provides "a technical overview of the development, manufacturing,
and future of contact lenses." It is written very clearly, it incorporates
many images, and even relates the properties of contact lens to their
chemical composition.
Section 4.6 Questions
p. 267
Question 14
Plastic cling wrap is widely used in our society. Why does
it cling well to smooth glass and ceramics, but not to metals? Describe
the controversial and social issue associated with use of this plastic
wrap. How are intermolecular forces involved in starting the process
that leads to this controversy?
Safety
of Plastic Food Wraps and Containers
This site, sponsored by the American Plastics Council, provides an excellent
overview of the issues regarding plastic wrap. It contains a broad set
of links to various other websites and articles that put forth various
arguments for and against plastic wrap.
Plasticisers
in Cling Film
This website from a British university first explains the role of plasticisers
in making cling wrap "cling," and then proceeds to describe
an experiment that can be performed to extract the plasticiser from
the wrap. This sort of experiment can demonstrate why it might be a
good idea to avoid using some cling wraps with oily foods.
New
Studies on Plastic Wrap and Cheese
This 1999 article from the New York Times describes the possibility
that some food wraps contain endocrine disruptors--chemicals that might
disrupt the body's hormonal balance.
p. 274
Practice
Question 10
Nitinol is known as the “metal with a memory.”
It is named after the alloy and place where it was accidentally discovered:
“Nickel titanium naval ordinance laboratory.” This discovery
has revolutionized manufacturing and medicine in the form of many products
that can “sense” and respond to changes. Research and write
a brief report about Nitinol including its composition, a brief description
of how it works, and some existing or proposed technological applications.
Nitinol
Technology
This industry website discusses the two properties of nitinol, "shape
memory" and "superelasticity," that make nitinol an extremely
useful compound.
p. 274
Practice
Question 11
The synthetic material moissanite (silicon carbide) looks like
diamond and is used to simulate diamonds in jewellery.
a. Compare the physical properties of moissanite and diamond.
b. Do these properties suggest a method to distinguish between a real
diamond and a simulated diamond like moissanite? Explain.
c. What test do jewellers use to distinguish between these materials?
Describe the principle used and the distinction made.
How
Moissanite Jewels Work
This set of websites from "How Stuff Works" explains the history
of moissanite jewls, and provides a comparison of the qualities of moissanite,
as compared with other gems. Finally, it describes the process of preparing
a moissanite gemstone.
The
Mineral Moissanite
This "Mineral Gallery" website provides a very useful and
instructive look at moissanite. It discusses its history in quite a
bit of details, and follows with a description of many of the mineral's
properties.
p. 275
Practice Careers
Choose a university and use its Web site to obtain biographical
information on one of its research scientists who is involved in research
of intermolecular structures. Report on the scientist’s training
and education qualifications, and briefly summarize the nature of his/her
current research project.
Ontario
Public University Addresses and Websites
This Ministry of Education website lists all Ontario universities along
with their contact information.
Section 4.6 Questions
p. 276
Question 11
Clays and ceramics are substances closely related to silica,
SiO2(s). List some properties of clay and ceramics. How does the structure
and bonding change when clay is fired (strongly heated) to produce a
ceramic?
A
Brief Primer on Clay
This website explains where clay comes from, how it is fired into different
shapes, and provides an extreme close-up photograph of clay.
Section 4.6 Questions
p. 276
Question 12
Research and report on the properties, applications, structure,
and bonding in boron nitride BN(s).
Boron
Nitride (BN) Powders for Use in Research and Industry
This corporate website explains the key properties of BN powder, and
images of the compound from afar and up close.
Question 13.
Experts agree that we are reaching the physical limit of how
many transistors can be put onto a computer chip of a given size. Some
scientists are already looking at a new generation of biological computers.
Research one proposed biological computer. Describe some similarities
and differences between this proposed computer and present computers.
What are some of the promises of this new technology?
Biological
Computer Born
This BBC News website discusses a new biological computer, affectionately
called a "leech-ulator," that uses neurons from leeches to
perform its computations. It is hoped that such biological computers
might one day be able to compute data with only partial information,
unlike today's compuers.
The
Biological Computer
This article discusses biological computers that might be the size of
cellular components. Israeli researchers have been working on such a
computer, the idea for which is based on the Turing machine of the 1930s.
Computing
Device to Serve as Basis for Biological Computer
This article from ScienceDaily.com discusses a mechanical computer that
has been built, and which will serve as a prototype for a biological
computer that will be built using a ribosome to replace the computer.
Chapter 4 review
p. 283
Question 27
What material is used in the outer skin of a stealth bomber?
Describe how the structure and properties of this material relate to
its function.
B-2
Spirit Information
You can access information on this site first by clicking in the Navigation
menu on the left-hand side of the screen--select "Structure & Systems."
You can then explore the site in a similar manner by choosing different
options from the drop-down menu.
