Buffer solutions:
A. work best when the pH of the buffer is two pH units above its pKa.
B. have a greater buffering capacity at lower concentrations.
C. buffer best when almost entirely in the conjugate base form.
D. have a characteristic Ka, which can be expressed as HA/A- H3O+.
E. do not change very much when H3O+ and OH- are added.
An acidic solution:
A. will have a pH greater than 7.
B. will have a pOH less than 7.
C. will have a very high concentration of hydroxyl (OH-) ions.
D. will have a H3O+ concentration higher than its OH- concentration.
E. will have a H3O+ concentration lower than its OH- concentration.
A pair of enantiomers are also stereoisomers. Why are pairs of stereoisomers not necessarily enantiomers?
What will be an ideal response?
Enantiomers are a pair of stereoisomers that are mirror images of each other. Which of the following would also be true of this pair of structures?
A. They will have different melting points.
B. They will have different densities.
C. They will have superimposable structures.
D. They will have the same molecular weight.
E. If basic molecules, they will have the same pKa.
Which of the following molecules are biologically active?
A. L sugars
B. L amino acids
C. only amino acids that are optically inactive
D. only sugars that lack chiral centers
E. All of these molecules are biologically active.
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