# 1. You have multiple vials of strong acid solutions hanging around….

1. You have multiple vials of strong acid solutions hanging around. You were suppose to label the vials with their pH, but forgot to do so before leaving for lunch. Luckily you did write down the H+ concentrations on them. If you need a solution with a pH around 9 for you next experiment which of the vials should you use?
The vial whose [H+] = 9.1×10-5 M
The vial whose [H+] = 1.8×10-5 M
The vial whose [H+] = 1.0×10-4 M
The vial whose [H+] = 6.5×10-10 M
2. What is the pH of a dilute solution of acetic acid (pKa=4.76) that has a conjugate base to weak acid ratio of 5:1? Please include two decimal places in your answer.
3. Aspirin is a weak acid with a pKa of 3.8. If you want more weak acid aspirin in your stomach than its conjugate base should you take the aspirin on a full stomach (pH=5) or an empty stomach (pH=2)?
A. empty (pH=2)
B. neither, you need the pH=3.8
C. full (pH=5)
4. Some amino acids are another example of amphipathic molecules. The amino acid alanine has a polar component that acts like a weak acid. The pKa of that region of the molecule is 2.35. Is that polar region of alanine protonated or deprotonated at pH=7.4 and does it have a charge?
A. deprotonated and it’d have a negative charge like the conjugate base of weak acids
B. protonated and it’d have a negative charge like the conjugate base of weak acids
C. deprotonated and it’d have no charge like a weak acid
D. protonated and it’d have a positive charge like the protons released by a weak acid
5. Ethane (CH3CH3) and ethanol (CH3CH2OH) are very similar in their molecular makeup. However, ethane is not very water soluble (its interaction with water is energetically unfavorable) while ethanol is very water soluble (energetically favorable interaction). What feature(s) of ethanol make(s) it more water soluble than ethane? Select all that apply.
ethanol can make H-bonds with water while ethane cannot
ethanol is bigger than ethane
ethanol is charged while ethane is not
ethanol is polar and ethane is nonpolar
ethanol has a lower boiling point than ethane