CHEM 121 Section 03 Midterm February 23rd 2010
NAME _______________________________________
This test has two parts and has 9 pages. A Datasheet should be provided
PART I consists of 16 Multiple Choice Questions and is worth 32 marks, The answers for
the questions in this part must be coded on the optical sense form
PART II consists of written answers and is worth 33 marks. Answer these questions on this
examination paper, show all your work.
Start Time 6.30pm -End Time 8.30pm
Marks for Written Answers
Question 1 [6]
Question 2 [2]
Question 3 [6]
Question 4 [2]
Question 5 [17]
Multiple Choice (/32)
Score (/65)
(% Score)
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CHEM 121 Section 03 Midterm February 23rd 2010
1.
The alcohol 4-methyl-1-pentanol contains all the following bonds except:
a.
b.
c.
d.
e.
2.
Which of the following is not a structural isomer of n-hexane?
a.
b.
c.
d.
e.
3.
4.
C-H
C=O
C-C
C-O
O-H
2-methylpentane
3-methylpentane
2,2-dimethylbutane
2,3-dimethylbutane
2,2-dimethylpentane
All the four alkanes shown below have the same formula C7H16.
Two of the four molecules are the same, i.e. they have the same IUPAC name, these
two molecules are:
a.
A nd B
b.
B and C
d.
B and D
e.
C and D
c.
The correct IUPAC name for the following alkane is:
a.
b.
c.
d.
e.
4-ethyl-2,3,4-trimethylheptane
2,3,3-trimethyl-4-ethylheptane
3-ethyl-2,3,3-trimethylheptane
3,4,5-trimethy-4-propylhexane
2,3-trimethyl-3-ethylhexane
2
A and D
CHEM 121 Section 03 Midterm February 23rd 2010
5.
The correct IUPAC name for the following alkane is:
a.
b.
c.
d.
e.
6.
2,3,4-trimethylhexane
2,3,4-dimethylhexane
4-ethyl-2,3-dimethylpentane
2,3,4-methylhexane
2,3,4-trimethylpentane
The (IUPAC) name of the alkane that results from the hydrogenation of the alkene
shown would be:
CH3
CH3
CH
CH3
C
H
a.
b.
c.
d.
e.
7.
H
2-methylpentane
4-methylpentane
3-methylpentane
hexane
isopropylpropane
Adrenaline and caffeine are essential for passing exams (structures shown below)
The functional group common to both molecules is a/an:
a. alcohol
8.
C
b. ketone
c. amide
d. amine
e. ether
Which of the following when reacted with an alcohol in the presence of an acid
catalyst would result in the formation of an ester?
a. ethanol
b. 2-propanone
d. methylamine
e. diethyl ether
3
c. butanoic acid
CHEM 121 Section 03 Midterm February 23rd 2010
9.
Which of the following would give an aldehyde when oxidized with a suitable
mild oxidizing agent
a.
d.
10.
b.
e.
CH3CH2CH2C=O
CH3CH2CH2COOH
c.
CH3CH2OH
c.
(iv) only
Which of the following molecules is/are chiral
a.
d.
11.
CH3CH2CH3
CH3CH(OH)CH3
(ii) only
(ii) and (iv) only
b.
e.
(i), and (iii) only
(i), (ii), (iii) and (iv)
In the following reaction the missing reagent and catalyst indicated by the ? are:
?
+ HCl
+ ?
CH3
12.
a.
CH3CH2Cl and FeCl3 b.
CH3Cl and AlCl3
d.
CH3Cl and H2SO4
CH3Br and FeBr3
e.
c.
CH3OH and HOCl
Which of the following would de-colorize an orange bromine solution?
a.
d.
benzene
2-propanol
b.
e.
heptane
Dichloromethane
4
c.
3-methyl-1-hexene
CHEM 121 Section 03 Midterm February 23rd 2010
13.
Consider the following reaction:
N2(g) + 3H2(g)
2NH3(g)
If the rate of appearance (formation) of NH3 at a given time is 6.0 x 10-4 Ms-1, what is
the rate of disappearance of hydrogen at this time
14.
a.
4.0 x 10-4 Ms-1
b.
6.0 x 10-4 Ms-1
d.
3.0 x 10-4 Ms-1
e.
18 x 10-4 Ms-1
c.
9.0 x 10-4 Ms-1
Consider the following for the gas phase reaction between nitric oxide and fluorine:
2NO(g) + F2(g)
2NOF(g)
The rate law predicts that the reaction is first order with respect to [NO] and first
order with respect to [F2]. When 0.5 M NO(g) reacts with 0.8 M F2(g), the initial rate
is 50 M s-1. Which of the following would be the correct rate constant for this
reaction?
15.
a.
8.0 x 10-3 M-1 s-1
b.
20 s-1
d.
125 M-1 s-1
e.
125 s-1
c.
8.0 x 10-3 s-1
The rate law for a gas phase reaction in which A + B + C → D is experimentally
observed to be Rate = k[A]2[C].
If the concentration of A, B and C are all doubled then the reaction rate will increase
by a factor of :
16.
a.
8
b.
6
d.
4
e.
9
c.
12
A first order reaction has a rate constant of 0.33 min-1. If the Initial concentration
of reactant is 0.50 M, what will be the concentration of reactant after 90 seconds?
*The integrated rate laws are given on the datasheet
a.
0.4 M
b.
0.002 M
d.
0.1 M
e.
0.3 M
5
c.
0.25 M
CHEM 121 Section 03 Midterm February 23rd 2010
Part II Written answers to questions
(6 Marks)
1.
Draw and name the three structural and geometric isomers of, C5H10, that have an
unbranched hydrocarbon chain containing one C=C bond, i.e. all the 5 carbon
atoms are connected in a straight chain, there are no cyclic structures.
(2 Marks)
2.
Draw the structure of 4-methyl-2-hexyne
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CHEM 121 Section 03 Midterm February 23rd 2010
(6 Marks)
3.
Give the products of the following reactions:
H
CH3
C
CH3
H2SO4
+ H2O
C
CH3
H2SO4
+ HNO3
H2SO4
+ CH3CH2OH
(2 Marks)
4.
Arrange the following compounds in order of increasing acidity using the scale
1,2,3,4 where 1 indicates most acidic and 4 least acidic.
H3C
O
CH3
OH
OH
7
OH
CHEM 121 Section 03 Midterm February 23rd 2010
5.
For the reaction: C2H4Cl2 + 3I-  C2H4 + 2Cl- + I3- the initial rate data at 60°C are:
[C2H4Cl2] (M)
[I-] (M)
Initial Rate (Ms-1)
Δ[I3-]/Δt
0.018
0.036
2.6 x 10-6
0.027
0.036
3.9 x 10-6
0.036
0.054
7.8 x 10-6
0.050
0.072
1.4 x 10-5
(4 Marks) (a) Calculate the reaction orders with respect to C2H4Cl2 and I- and therefore
write the rate law for the reaction: (Show your work)
(2 Marks) (b) What is the value of the rate constant based on the data, show correct units.
(2 Marks) (c) Write an equation to show how the rate of disappearance of I-, Δ[I-]/Δt, is
related to the rate of appearance of I3-, Δ[I3-]/Δt.
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CHEM 121 Section 03 Midterm February 23rd 2010
(4 Marks) (d) What is the rate of disappearance of I- when [C2H4Cl2] = 0.020 M and
[I-] = 0.040 M
(2 Marks) (e) Iodine-125 (125I), is used to test for thyroid function, it decays according to
first order kinetics with a rate constant for radioactive decay of:
k = 0.011 day-1.
Calculate the half-life (in days) of 125I.
(3 Marks) (f) When 90% of the Iodine-125 (125I) has decayed the dose is no longer
effective. Calculate the number of days required for the dose to decay to 10%
of the initial concentration.
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