Download Group Project 4

Group Project #4
The logarithmic scale measures the acidity levels of substances with the following
equation:
pH   log[ H  ]
where [H+] is the concentration of the hydrogen ions in the substance. pH values
typically range between 0 and 14. Things with a pH of 7, such as pure water, are called
neutral, whereas items with a pH below 7 are called acidic and items with a pH above 7
are called basic. For more information on the pH scale, see text pages 346-348.
-------------------------------------Kevin, an ulcer patient, has been told to avoid acidic foods. If he drinks wine, with a pH
of 4, it bothers him, but he can tolerate tea, with a pH of 5.5, and pure water, with a pH of
7.
1.
Kevin wants to know if a mixture of half wine and half pure water will be at least
as tolerable as tea (i.e. have a pH of at least 5.5).
a.
Find the hydrogen ion concentration, [H+], of both wine and pure water.
b.
Find the hydrogen ion concentration, [H+], of a mixture of half wine and
half pure water.
c.
What is the pH of the mixture of half wine and half pure water? Is it as
tolerable as tea?
2.
Kevin wants to make a wine-water drink that has a pH of exactly 5.5.
a.
Using p to represent the decimal representation of the percentage of wine
in the drink and (1-p) to represent the decimal representation of the
percentage of pure water in the drink, write an expression for the hydrogen
ion concentration, [H+], of his wine-water drink.
b.
Determine the percentage of wine and pure water that he should mix to get
his desired 5.5 pH level. You can do this by solving algebraically or using
a graphing utility (just make sure to include an excel graph with your
answer).