CHEM104
spring 2003
1) For the reaction
2
SO2 + O2 --> 2 SO3
which of the following statements are
true?
a)
The overall reaction is third order.
b)
The instantaneous reaction rate = - d[O2]/dt
c)
The rate law = k[SO2]2[O2]
d)
none of the above
2) What are the correct units for the rate constant, k, in a second order reaction?
Starting with: rate = k[rgt]2,
M/sec = k (M)exp2
So:
k = M/sec x(1/Mexp2)
Then: k = 1/(M sec)
3) For the reaction: 2NO +
O2 --> 2NO2
if the rate D[NO2]/Dt = 0.005 mol L-1
sec-1, what is the rate of disappearance of O2?
[O2]
will react one half as fast as NO2 is formed, or
(1 mole O2/ 2 moles NO2) x 0.0005 M NO2/sec = 0.0025 M O2/ sec
4. For the general
reaction: A + B -> C
the rate of reaction was
measured as a function of varying the initial concentration of one of
the reactants. These results are
summarized in the plot below right.
What is a reasonable
conclusion for this plot?
(a) The plot shows that rateo = k [A]o
(b) The plot shows that rateo= k [C]o2.
(c) The plot shows
that rateo= k [A]o2.
(d) The plot shows no
dependence on [A].
5. For the nuclear reaction:
99Tc ---> 99m Tc + gamma radiation
a plot of the concentration of 99Tc vs. time is below. What is true about this reaction?
(a) The change in
[99Tc], M , is constant.
(b) The concentration of 99Tc decreases
with time and this decrease slows down as
reaction progresses.
(c) The rate law for the reaction is order
in 99Tc.
(d) The equilibrium constant
for reaction is large.