Web Activities
UNIT 1: ORGANIC CHEMISTRY
Unit 1 – Performance Task and Review
Unit 1 Review
p. 154
Question 23
The compound p-aminobenzoic acid (PABA) is the active ingredient
in some sunscreen lotions.
a. Draw a structural diagram for PABA.
b. Predict some properties of PABA such as solubility, melting point,
and chemical reactivity.
c. Research, using electronic or print resources, the properties of
PABA, explanations of its role against UV radiation, and any possible
hazards in its use to the wearer or to the environment.
Facts
About Sunscreens
This site belongs to the "Patient Information" group of sites
of the American Academy of Dermatology. It contains a very helpful list
of questions and answers that explain in detail how sunscreen works.
Sunscreens
and Sunburns
This Altruis Biomedical Network site explains the process of sunburning,
as well as the mechanism of sunscreen action. It also details the many
ingredients (including PABA) that might be found in sunscreens, and
evaluates their effectiveness.
Question 24
Research the use of chlorinated hydrocarbons as solvents in
the removal of contaminants from microchips in the manufacture of computers.
Write a report discussing
a. any hazards in the use of chlorinated hydrocarbons; and
b. other polymers that have been used by the computer industry as
cleaning agents for microchips.
Micell
Technologies, Inc.
This web-page explains the challenges faced by Micell Technologies in
developing a new system for dry-cleaning, using liquid carbon dioxide.
It also discusses the potential advantages for the environment if such
a change in the industry was to be made.
Environmental
Issues in Semiconductor Manufacturing
The middle of this web-page, maintained by the (American) State Science
& Technology Institute, addresses the industry concern that perhaps
too much water is being used to clean semiconductors, and that perhaps
alternatives to glycol ethers can be found for cleaning solvents.
Environment-Friendly
Chip Design
A part of the NewsFactor Network, this article explains the new techniques
that several different companies are working out to make the manufacturing
of computer chips and semiconductors more environmentally-friendly.
Question 25
There is ongoing research in the development of polymeric materials
for use in dentistry and related fields, such as cranial and facial
restoration. Polymers used to make dental impressions, for example,
require certain properties, including low solubility, high tensile strength,
and a high softening temperature.
Research current practice and recent advances in the use of
organic polymers in the dental industry and the dental profession. Write
a report on your findings, covering the following topics.
• The desired properties of dental polymers and the
shortfalls of available materials
• The key structural features of the monomers in current and
prospective dental polymers
• The rate and degree of the formation of crosslinks between
polymer chains, and properties of the structural matrix formed
• The pros and cons of different methods of initiating the polymerization
process
• The role of hydrogen bonding on the physical and mechanical
properties of the polymer
Dental
Polymers
This website is provided by the Polymers Division of the National Institute
of Standards and Technology. It describes a project on which the NIST
is embarking to provide a knowledge base for the dental profession regarding
polymeric dental materials.
Laser
Curing Dental Polymers
Scroll down to item #4 on this list of new research projects sponsored
by the Delaware State University. The described project will attempt
to prevent dental fillings detaching from the tooth cavity wall due
to shrinkage.
Why
Not White Fillings
This website provides an instructive list of questions and answers regarding
"white fillings," providing a balanced view of their advantages and
disadvantages as compared with traditional silver fillings.
Improving
the Treatment of Cavities
This article appears in an online journal called "The Mission,"
sponsored by the University of Texas at San Antonio. It discusses the
use of newer, modern fillings, and their effectiveness in preventing
cavities. The article also includes some helpful diagrams.
p. 155
Question 26.
Various chromatographic methods are used for the separation
of mixtures into their individual components. The mixture is adsorbed
onto a stationary support such as a gel, and the compounds are separated
by differences in polarity and molecular size. Research one of the following
aspects of chromatography, and write a report to present your findings.
• The selective use of solvents in liquid chromatography
to separate compounds with differences in solubility in the solvent
• The structure and properties of proteins and nucleic acids
that allow their purification through electrophoresis
• The features of a gas chromatography system used in the analysis
of trace amounts of organic substances such as illicit drugs or pesticides
• The structure and properties of synthetic polymers, such as
polyacrylamide, used as stationary support in gel electrophoresis
High
Performance Liquid Chromatography
Provided by a research group at the University of Kentucky, this website
introduces HPLC and provides several links that can be followed for
explanations regarding the technique's history, operation, manufacturing,
and troubleshooting--an excellent and detailed overview.
Gas
Chromatography
This University of Akron web-page describes several aspects of gas chromatography,
and includes several diagrams and pictures of the machinery and the
process.
Liquid
Chromatography
This University of Akron website introduces the process of liquid chromatography,
and describes the process using several easy-to-read slides along with
diagrams and pictures.
Question 30
Polymers can be made from other substances, besides organic
monomers. One of the more familiar is silicon. Research its structure,
manufacture, properties, and uses. Conclude with an example of a situation
in which the use of silicone has provided some benefits and some drawbacks.
What
is Silicone?
This site is maintained by the Independent Review Group in the United
Kingdom. This page distinguishes silicone from various other chemical
compounds like silica and silicon. The basic physical and chemical properties
of each of these chemicals is explained.
Silicone
Chemistry
This excerpt comes from a book, entitled, "Safety of Silicone Breast
Implants," and includes a brief overview of silicone materials,
as distinguished from silicon and silica.
Specialty
Silicone Products, Inc.
This is the corporate website of a company that researches and manufactures
several silicone products.
What
is a Silicone?
This corporate website of Sil-Tech explains briefly what silicone is.
