Cell Bio Lab Midterm Exam, Fall 2023
Name Date
Multiple choice (1.25 each) Total test grade 100
1- How are the pOH and pH linked?
a. pH + pOH = 14
b. pH = 7 + pOH
c. pH - pOH = 14
d. pOH + 7 = pH - 7
e. pH + pOH = 10
2- acids completely dissociate in water and donate ______
a. Weak, all protons
b. Strong, half protons
c. Strong, all protons
d. Weak, half protons
3- What will happen if we lower the hydrogen ion concentration?
a. The pH will be lower
b. Hydrogen ion concentration of a solution cannot be changed
c. The pH will be higher
d. The pH will be the same.
4- If you have a glass of pure water, without any acids or bases, how many hydronium ions ($H_3O^+$)
do you expect?
a. As many as there are water molecules
b. The same number as $OH^-$
c. Half the water is hydronium ions
d. None
5- What's the difference in concentration of hydronium ions between pH 1 and pH 4?
a. $\times$ 1000
b. $\times$3
c. $\times$4
d. $\times$10
6- Does the intake of acidic or alkaline foods affect the blood pH?
a. Yes, acidic food decreases pH and alkaline food increases it.
b. No, the blood pH fluctuates randomly.
c. Yes, the pH increases after eating.
d. No, the blood pH is constant.
7- Which of the following classes of buffers we need to make a chemically stable buffer for
biochemical reactions, with a pH in the range of 3.75 to 5.50
a. Bis-Tris (pKa:6.5)
b. citrate (pKa 3.13)
c. Acetate (pKa: 4.75)
d. Succinate (pKa:5.56) e. All of the choice would be appropriate
8- Buffer solutions
a. will always have a pH of 7.
b. are rarely found in living systems.
c. tend to maintain a relatively constant pH
d. cause a decrease in pH when acids are added to them.
