Web Activities
UNIT 4: CHEMICAL SYSTEMS AND EQUILIBRIUM
Chapter 8 – Acid-Base Equilibrium
Practice
p. 546
Question 16
d. There is some research that suggest that women’s diets
may affect the likelihood of their getting pregnant, as sperm are sensitive
to pH. Research this topic, and make some diet suggestions for a woman
who is trying to get pregnant.
Becoming
Pregnant
Practical advice is provided on how to maximize the chances of becoming
pregnant.
Pregnancy
and Essential Fats
The factors that can prevent pregnancy are listed.
Can
Acid Levels Kill Sperm
This page describes how unusually low vaginal acidity can kill sperm.
Infertility
This site provides a good overall summary of the causes of infertility
for men and women, methods of diagnosis, treatments, and coping strategies.
p. 546
Question 6
When food enters the stomach, it stimulates the production
and secretion of hydrochloric acid for digestion, reducing the pH of
the stomach contents from 4 to 2.
a. Compare the [H+(aq)] before and after the change in pH.
b. Conduct library or Internet research to find out how the stomach
protects itself from the corrosive effects of this low pH level.
How
Does Your Stomach Keep From Digesting Itself
The layers of the stomach and their function are described as well as
detailed information of how the stomach protects itself from being digested.
NSAIDS
and Peptic Ulcers
This page provides basic information on how the stomach protects itself
from the digestive juices it secretes. Information about the formation
of peptic ulcers is also provided. Medications used to treat disorders
of the stomach lining are also mentioned.
Stomach
and Duodenal Ulcers
This comprehensive page describes what ulcers are, their causes, symptoms
and possible treatment.
Ulcers
- A Microbial Infection?
This article describes heliobactor pylori, a bacterium responsible for
stomach ulcers and how the bacterium is adapted to surviving the hostile
environment of the stomach. Treatments to rid the stomach of this pest
are also mentioned.
Section 8.1 Questions
p. 550
Question 9
Conduct library or Internet research to obtain information
to answer the following questions about gastroesophageal reflux disease,
GERD.
a. What is GERD?
b. Who is usually affected by this condition?
c. Describe the apparatus used to diagnose this condition.
d. What treatments are currently available for this disease? Include
examples of chemotherapeutic and surgical interventions.
An
Introduction to GERD
This website contains an overview of GERD; animations of general acid
reflux; parietal cell acid production (i.e., the cells in the stomach
lining that produce acid); an animation of gastroesophageal reflux;
symptoms and possible causes of GERD.
GERD
Online
This site is an online information database for patients with GERD.
It offers an overview of the disease, FAQ’s , medical advice and
a description of surgical procedures used to treat GERD.
Understanding
GERD
This page, maintained by the American College of Gastroenterology, provides
general information on heartburn and GERD, treatments for heartburn,
and the complications that can arise from GERD.
p. 550
Question 10
Conduct library or Internet research to answer the following
questions regarding acid-free paper.
a. What is acid-free paper? Why is it called “acid-free”?
b. What are the primary uses of acid-free paper?
c. List advantages and disadvantages of its use.
Basic
Facts About Paper Deterioration
Background into paper deterioration and current techniques used to deacidify
paper is provided.
Chemistry
of Aging
This document is part of a larger text on the deterioration of materials
as they age. Detailed information on the acid hydrolysis of paper is
provided.
Paper
Decay
This page provides a comprehensive summary of why acidic paper decays,
how paper decay can be monitored, and methods currently in use to preserve
acidic paper.
Conservation
of Library and Archival Materials
This comprehensive document provides current information about paper
decay, how acidic paper can be treated and paper storage concerns.
Section 8.2 questions
p. 580
Question 21
Aniline, C6H5NH2, is a colourful weak base closely related
to ammonia, NH3.
a. If the pH of a 0.10 mol/L aniline solution is 8.81, calculate the
Kb for analine.
b. Aniline has been used as a pigment for centuries. What colours
are aniline dyes? How do the colours of aniline dyes vary with pH?
Research and write a short report on aniline dyes.
Dyestuffs
and Dyeing of Leather
This page describes the basics of modern dyeing techniques. It also
compares the chemistry of anionic, amphoteric, and cationic dyes (including
aniline).
Ruglore:
Dyes
This page compares natural and synthetic dyes and provides an overview
of the history of dyes in rug manufacturing.
Mauve:
How One Man Invented a Colour That Changed the World
This page also describes William Perkins’ discovery of mauve and
provides an interesting insight in Perkin, the inventor and entrepreneur.
p. 580
Question 22
The stomach wall has a protective mucous lining that prevents
stomach acid from attacking the underlying tissues. Frequent use of
Aspirin (acetylsalicylic acid), HC8H7O2CO2(aq), can damage the stomach
wall. Aspirin is a weak carboxylic acid with a Ka of 3.2 x 10-4.
HC8H7O2CO2(aq) [eqm symbol]
H+(aq) + C8H7O2CO2(aq)
a. Stomach acid has a pH of about 1.5. Given the acidity of
the stomach, would Aspirin dissolved in stomach fluid be mostly in
its ionized or un-ionized form?
b. Un-ionized Aspirin molecules can readily penetrate the stomach
lining into a region of less acidity. This is where stomach irritation
associated with Aspirin occurs. Use Le Chatelier’s principle
to explain why irritation occurs in this area.
c. Conduct library or Internet research to obtain information on enteric-coated
tablets or capsules. How do these help alleviate the problems described
in (a) and (b)?
Aspirin
A summary of the history of aspirin, its uses, properties and chemical
structure is provided.
How
Aspirin Works
This site gives a detailed history of the discovery of aspirin, aspirin’s
properties and chemical structure, its uses, and complications that
can arise from its use.
Peptic
Ulcer Disease
This page describes peptic ulcers, their causes, symptoms, diagnosis,
and treatment.
Pain
Relievers and Intestinal Disorders
Aspirin is an example of a class of drugs called nonsteroidal anti-inflammatory
drugs (NSAIDs). This site gives a thorough discussion of why NSAIDs
can damage the stomach, symptoms of NSAID-induced damage and ways in
which it can be avoided.
p. 580
Question 23
During a cross-country race, the concentration of lactic acid
in the fluid surrounding muscles can be 5.6 mmol/L. Given that the Ka
for lactic acid is 7.94 x 10-5, calculate the pH of the fluid around
the muscles of a runner.
a. What are the symptoms of lactic acid buildup in the muscles?
b. Long-distance runners make use of a quantity called the lactic
acid threshold (or lactate threshold) to help them avoid lactic acid
buildup. Describe the lactic acid threshold and explain how runners
make use of this value in training and competition.
The
Lactate Threshold
This document describes what lactic acid is, the chemical and physiological
changes that occur in muscle tissue during exercise, the effect of lactic
acid concentrations on athletic performance, measuring lactate threshold
and how to raise an athlete’s lactate threshold.
Elevating
Your Lactate Threshold
This page describes the physiological changes that occur as athletes
work at their lactate threshold. Lactate threshold heart rate (LTHR)
is introduced as a key indicator of a tri-athlete’s fitness.
Lactate
Threshold
This document defines what lactate threshold is and how to utilize lactate
threshold to make training more efficient.
Practice
p. 591
Question 11
Many communities are against the addition of fluoride to municipal
drinking water. Conduct library and Internet research to learn more
about this issue. List arguments for and against this practice and write
a brief position paper.
Fluorides
and Human Health
This page, provided by Health Canada, describes why fluoride is added
to drinking water, the health risks of excessive fluoride consumption,
and the federal government’s role in maintaining water quality.
CDA
Statement on Fluoridation
This document is the Canadian Dental Association position paper on fluoridation.
Fluoride:
Hidden Danger in Your Drinking Water and Toothpaste
This page describes why fluoride is used and the concerns with adding
fluoride to our water supply.
Case Study
p. 624
Question 3
c. Conduct library or Internet research to learn about the
techniques (in addition to those described here [in the Case Study])
being currently used to increase the buffering capacity (buffering ability)
of granite-based lakes.
Acid
Rain
This page defines acid rain, identifies sources of the pollutants responsible
for acid rain, and describes the environmental effects of acid rain
and possible solutions.
Liming
Acidified Lakes and Ponds
Specific information regarding the use of lime to mitigate the effects
of acid deposition is given.
Acidification
of Watersheds
This page describes the formation of SOx and NOx; the environmental
impact of acid deposition; the chemistry of liming; and a summary of
past, current and future possible acid rain management practices.
Explore an Issue – Take a Stand: Acting to Reduce the Effects
p. 624
a. Knowing some of the likely causes of acid deposition, research
and suggest at least one action that North Americans could take to reduce
the negative effects of acid deposition.
Unfinished
Business: Why the Acid Rain Problem is Not Solved
This document gives current background into the sources of the pollutants
responsible for acid deposition, the chemical changes that occur in
soil and aquatic ecosystems as a result of acid deposition, the extent
of the damage caused by acid deposition in North America, and a reflection
on what still needs to be done to alleviate the problem.
Sources
of Acid Rain-Causing Emissions
This page describes the sources of SOx and NOx emissions, the chemical
reactions that produce SOx and NOx, the adverse effect of acid deposition
on the environment, a case study, and possible solutions.
Air
Pollution
This page gives a good overview of air pollution in general, including
acid deposition. The graphics provided would be useful for student presentations.
Careers Practice
p. 625
Question 2
Select one of the careers mentioned (or a similar career of
your choice) and find
a. at least three universities that provide the necessary
degree(s);
b. what tuition fees are at each of the universities;
c. what scholarships or bursaries are available to students taking
these degrees.
Welcome
to EnviroCareers
Job descriptions and educational requirements for a variety of careers
in the environmental sciences are provided. Chemistry-specific careers
are listed in the “Protect” and “Explore” tabs.
CareerMatters
TV Ontario operates this career database. For each career, a description,
specific duties, education, career path, and sometimes a videotaped
interview are provided.
JobFutures2000
This resource, provided by Human Resources Development Canada, is a
searchable database of careers. It provides a snapshot of 211 occupational
groups; provides work experiences of recent post-secondary graduates
and future outlooks for 155 different careers; and general information
about the Canadian labour market.
Chapter 8 Review
p. 633
Question 23
Many antacids contain carbonates such as CaCO3, MgCO3, and
NaHCO2, as their active ingredients. Other antacids are based on hydroxides
such as Al(OH)3 and Mg(OH)2.
a. Write a chemical reaction to
show how hydroxide antacids neutralize excess stomach acid.
b. Bicarbonate-based antacids, which contain HCO3 as the active ingredient,
are very common. Consuming excess bicarbonate can lead to a medical
condition called alkalosis. Conduct library or Internet research to
determine the chemical equilibrium that is involved in alkalosis.
c. Visit a drugstore and examine antacid labels. Which active ingredient
is most common?
Acidosis
and Alkalosis
A definition of acidosis and alkalosis is provided as well as a description
how athletes minimize alkalosis.
Alkalosis
This site lists the causes, symptoms, preventative measures associated
with alkalosis.
pH
and Buffers
This site provides a good summary of how sensitive biological systems
are to slight changes in pH.
