Biochemistry Exam 1 Flashcards
Hydrophobic interaction between non polar molecules
require the presence of surrounding water molecules
If pK values for phosphoric acid are 2.15, 6.82, and 12.38, at what PH would one observe equal amounts of H2PO4-, and HPO42-
6.82
What is the ph of a solution with a OH- of 4.1 x 10^-3 M
11.61
The pH at the midpoint in the titration of an acid with a base is
equal to the pK of the corresponding acid
Which of the following statements about water is not true?
in the liquid state it is only 15% less hydrogen bonded than in the solid state at 0 degrees celsius
The capacity of buffer to resist changes in pH upon addition of protons or hydroxide ions depends on
all of the above (the pea, the ph, the total concentration)
In a hydrogen bond between a water molecule and another biomolecule,
The hydrogen bond will typically form between a hydrogen atom and either a nitrogen, sulfur, or oxygen atom
The ph of coffee is 5.6. The pH of grapefruit juice is 2.6. This means that the proton concentration in coffee is
1000 times lower than In grapefruit juice.
What is the conjugate base in the product of the following reaction
H2SO4-
Molecules such as methanol and ethanol are very soluble in water because
They contain 0-H groups that can form multiple H bonds with water
The 104.5 bond angle in the water molecule is the results of the _ arrangement of electron orbitals around oxygen
Tetrahedral
When considering O,N, and F, the shortest hydrogen bond with -OH group would be formed with _ since this atom is the most _ in the group.
F, and electronegative
A strong acid is completely ionized in water, where as weak acid is
only partially ionized
Which of the following is a physical property of water that results from hydrogen bonding?
all the above ( high boiling, a solid state, high surface tension, the ability to solubilize polar molecules
A sample of gastric juice has a PH of 1.20. What is the concentration of hydronium ion in this sample?
6.3 x 10-2 M
