8) A solution is prepared by dissolving 0.23 mol of benzoic acid and 0.27 mol of
sodium benzoate in water sufficient to yield 1.00 L of solution.The addition of 0.05 mol
of NaOH to this buffer solution causes the pH to increase slightly. The pH does not
increase drastically because the NaOH reacts with the ________ present in the buffer
solution. The Ka of benzoic acid is 6.3 x 10-5.
A) H2O
B) H3O+
C) benzoate
D) benzoic acid
E) This is a buffer solution: the pH does not change upon addition of acid or base.
9) Which of the following is (are) not a typical source of nitric oxide?
A) livestock emissions
B) atmospheric electrical discharges
C) internal combustion engines
D) combustion of organic matter
E) all of the above
10) The equilibrium constant for the gas phase reaction
N2 (g) + O2 (g) 2NO (g)
is Keq = 4.20 x 10-31 at 30 oC. At equilibrium, ________.
A) products predominate
B) reactants predominate
C) roughly equal amounts of products and reactants are present
D) only products are present
E) only reactants are present
11) A sample of oxygen gas (O2) was found to effuse at a rate equal to three times that
of an unknown gas. The molecular weight of the unknown gas is ________ g/mol.
A) 288
B) 96
C) 55
D) 4