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8/2/2019 Tutorial Water Chemistry 112
http://slidepdf.com/reader/full/tutorial-water-chemistry-112 1/2
SBK3
1. The formation of ice dur
winter. Why?
2. Give one example to de
3. In Europe, engineers d
small gap to prevent th
account for this design?
4. Identify the type of bondi
more than one type, nam
5. How many water molecul
glyceraldehyde, shown h
6. Calculate the pH of the f
i. 5 x 10-4 M
ii. 1 x 10-4 M
iii. 3 x 10-2 M
iv. 7 x 10-5 M
7. Calculate the [ H+ ] and [
i. Saliva,
ii. Intrac
iii. Tomat
iv. Grape
TUTORIAL
013 PRINCIPLE IN BIOCHEMISTRY
WATER CHEMISTRY
12/3/2012
ing colder weather helps to temper the seas
onstrate the property of water cohesion and a
sign city sidewalks using blocks of concrete
m from cracking. What property of water is
riefly explain your answer.
g between each pair of atom and molecules. I
e the type of bonding indicated by arrow.
es could hydrogen bond directly to the one mol
ere?
llowing aqueous solutions:
HCl
NaOH
KOH
NaOH
OH- ], for each of the following materials:
pH 6.5
llular fluid of liver, pH 6.9
o juice, pH 4.3
ruit juice, pH 3.2
nal transition to
hesion.
separated by a
being taken into
examples with
ecule of
8/2/2019 Tutorial Water Chemistry 112
http://slidepdf.com/reader/full/tutorial-water-chemistry-112 2/2
8. What is the [ CH3COO- ]/ [ CH3COOH ] ratio in an acetate buffer at the following pH:
a. pH 4.00?
b. pH 5.00?
9. What is the pH of a buffer solution that contains:
a. 75% lactate form and 25% lactic acid?
b. 25 ml of 1.0 M lactic acid and 75 ml of 1.0 M sodium lactate.
10. Calculate the pH of a buffer solution that contains:
a. 0.10 M acetic acid and 0.25 M sodium acetate.
b. 10% acetic acid and 90% sodium acetate.
11. If the internal pH of a muscle cell is 6.8, what is the [ HPO42- ]/ [ HPO4
- ] ratio in this cell?
12. Suggest a suitable buffer range for each of the following substances:
a. Lactic acid and its sodium salt
b. Acetic acid and its sodium salt
13. You need to carry out an enzymatic reaction at pH 8.7. There are only two weak acids
available in the lab, one with a pKa of 8.3 and one with a pKa of 6.8.
a. Which substance and its conjugate base will you choose to make a suitable
buffer? Explain your reason.
b. What would be the ratio of the conjugate base/ conjugate acid of the buffer made
from the weak acids?
14. The pH of normal rainwater is approximately 5.6. The slight acidity compared to pure
water is caused by dissolved CO2. In some regions of the world, the acidity of rain has
increased to a pH of approximately 3.5.
a. Compare the hydrogen ion concentration [H+] in acid rain and the normal
rainwater?
b. Calculate the ratio of bicarbonate to carbonic acid in normal rainwater and in acid
rain.
c. Assume that acid rain has lowered the pH of a lake to pH 5.0. What is the
hydroxide ion (OH-) concentration of this lake?
15. a. Briefly explain what is monoprotic acid and polyprotic acid.
b. Draw the titration curve for each of the following acids. Assume they are titrated
with NaOH. Indicate the pKa and inflection point of each acid.
i. Benzoic acid
ii. Malic acid
iii. Citric acid
Please do the tutorial individually. Pass up the tutorial next week during lecture 19/3/2012.