CHM 365
Problem Set 1
Chapter 1 and 2
1. Draw the hydrogen bond(s) that are likely to form between the following pairs of molecules:
a) methanol and water
b) two molecules of ethanol
2. Calculate the pH of a) 0.1 M HCl b) 0.1 M NaOH c) 3x10-5 M HNO3 d) 5x10-10 M HClO4
and e) 2x10-8 M KOH
3. a) Sketch the titration curve for carbonic acid (H2CO3, pKa=6.4) (HCO3-, pKa=10.2)
4. a) The pKa of ascorbic acid is 4.2 at 24°C. At what pH is the ratio of the unprotonated to protonated
forms of ascorbic acid 1:3?
b) Which form predominates at physiological pH?
5. Distilled water in equilibrium with air contains dissolved CO2 at a concentration of 1.0x10-5 M. Given
that the Keq is 4.47x10-7, calculate the pH of such a solution.
6. If 100 mL of a 0.10M NaOH solution is added to 75mL of a 0.15M HCl solution, then what is the pH of
the resultant solution?
7. Consider the titration of 30 ml of 0.20 M acetic acid, CH3CO2H, with 0.10 M NaOH:
Ka (CH3CO2H ) =1.8x10-5 : Kb (CH3CO2-) =5.6x10-10 (16 pts)
a) What is the pH of the solution after 50 ml of NaOH has been added?
b) What is the pH at the equivalence point of the titration?
8. If the pH of a patient’s blood plasma is 7.2 and the HCO3- concentration is 18 mM, then how much CO2
is dissolved in the blood? The Keq is 7.94x10-7
9. A plasma sample had P(CO2) 28 mm Hg and [HCO3-] 15 mM. What are the pH and the [HCO3-]/[CO2]
ratio? Is it more acidic than normal?
10. A buffer solution consists of 0.50 M nitrous acid (HNO2) and 0.60 M sodium nitrite (NaNO2).
Ka=4.5x10-4
a) What is the pH of this buffer solution?
b) What is the pH when 10.0 ml of 3.0 M HCl is added to 250 ml of buffer solution?
11. Match the organelles with their function.
Organelle: Function:
Nucleus a) Oxidative reactions involving O2
Mitochondria b) Synthesis of phospholipids; synthesis of membrane and secretory
proteins
Endoplasmic Reticulum c) Intracellular digestion
Golgi d) Contains genetic material
Lysosome e) cellular respiration and energy conservation
Peroxisomes f) modification and sorting of protein products
Membrane g) transport of ions and molecules