#Question id: 361
#Unit 1. Molecules and their Interaction Relevant to Biology
Calculate the percentage of histidine that has its imidazole side chain protonated at pH 7.3. The pKa values for histidine are pK1 = 1.8, pK2 (imidazole) = 6.0, and pK3 = 9.2.
#Question id: 362
#Unit 1. Molecules and their Interaction Relevant to Biology
A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?
#Question id: 363
#Unit 1. Molecules and their Interaction Relevant to Biology
What is the pH of a mixture of 0.042 M NaH2PO4 and 0.058 M Na2HPO4? If 1.0 mL of 10.0 M NaOH is added to a liter of the buffer prepared, how much will the pH change? (pKa = 6.86)
#Question id: 364
#Unit 1. Molecules and their Interaction Relevant to Biology
A solution contains 0.0000001 (10-7) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?
#Question id: 365
#Unit 1. Molecules and their Interaction Relevant to Biology
Water is a polar molecule: the oxygen atom with its unshared electrons carries a partial negative charge (δ−) of ___________, and the hydrogen atoms each carry a partial positive charge (δ+) of __________, where e is the charge of the electron.
#Question id: 366
#Unit 1. Molecules and their Interaction Relevant to Biology
What is the pH of a solution with a hydroxyl ion (OH-) concentration of 10-10 M?