Chem 162
Quiz 1t
Name______________
Show work on all problems for full credit
1) (5 points) For the reaction, HI (g)  H2 (g) + I2 (g), the rate of formation of I2 is 2.0 x 10-5 M•s-1
a) Symbolically write expressions for the rate of reaction in terms of each reactant and product.
b) Calculate the rate of disappearance of HI.
c) Determine the rate of reaction.
d) Calculate the final concentration of HI when [HI]0 = 5.00 M decomposes over 2.50 x 103 s. Assume that the rate is constant
during the time interval.
2) (8 points) The rate of reaction between hemoglobin (Hb) and carbon monoxide (CO) was studied at 20 °C. The
following data were collected with all the concentration units in mol/L. (2.21 mol/L = 2.21 x 10-6 mol/L)
Trial
1
2
3
[Hb]0,
mol/L
2.21
4.42
4.42
[CO]0,
mol/L
1.00
1.00
3.00
Initial Rate, mol/L • s
0.619
1.24
3.71
a) Determine the orders of each reactant, Hb and CO. This can be calculated or stated in words for full credit.
b) Write the complete rate law for this reaction.
c) Calculate the value of the rate constant, using trial 2. Be sure to include the units.
d) Calculate the initial rate for an experiment with [Hb]0 = 3.50 mol/L and [CO]0 = 1.80 mol/L.
3) (8 points) Answer the following questions using the data table shown to the right for the reaction,
Z ------> products.
a) Determine the order (0, 1, or 2) of [Z] using the half-life method.
b) Solve for one value of k base on your choice of order. Be sure to include the units of k.
c) Calculate the rate of reaction at [Z] = 0.75 M?
d) How long (in ms) will it take for [Z] = 0.05 M?
e) What you did for part a involves inductive logic. You now must demonstrate deductive logic.
Eliminate one other order using the constant k method. Three k calculations are required.
.
Time
(ms)
0.00
0.10
0.32
0.60
0.80
1.10
1.50
3.00
9.00
18.00
31.00
4) (4 points) Circle all the true statements.
a)
Increasing temperature increases the rate of reaction by increasing the number of collisions.
b) A reaction is known to be 2nd order in [A]. When [A] is tripled (3x) the rate increases 27-fold (27x).
c)
A linear plot of –[X]/t for X Y has a slope = 0. The order of [X] is 1 st.
d) The overall order of a reaction with rate = k[A] 2[B]-1[C]3 is 4.
e)
If the slow step of a reaction requires light to start, the reaction is 1st order in the reactant.
f)
For a 1st order reaction after 3 half-lives have passed, 87.5% of the reactant has reacted.
g) The time is takes a 0th order reaction to go from [A]0 = 10.0 M to [A] = 5.0 M with k = 2.0 x 10 -1 M/s is 3.5 s.
[Z]
(M)
10.00
8.00
5.56
4.00
3.33
2.67
2.11
1.18
0.43
0.22
0.13
h) The initial rate method and integrated method for rate law determination are tools for examining the effect of the
orientation/complexity of the collisions involved in a chemical reaction.