Quiz Results
Question 1
The correct hybridizations of the atomic orbitals on the atoms labeled 1, 2 and 3 are (respectively)?
sp2, sp2, and sp2
sp2, sp3, and sp2
sp, sp2, and sp2
sp, sp3, and sp2
sp, sp3, and sp3
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Question 2
Which one of the following derivatives of ethane has the highest boiling point?
C2Cl6
C2I6
C2Br6
C 2 H6
C 2 F6
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Question 3
The correct systematic (IUPAC) name for the molecule above is:
cis-3-pentene
trans-2-pentene
trans-2-propene
cis-2-pentene
cis-1-methyl-1-butene
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Question 4
Pentane has __________ structural isomers.
2
4
0
1
3
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Question 5
Which statement about hydrocarbons is false?
The smallest alkane to have structural (constitutional) isomers has 4 carbon atoms.
Alkanes can be produced by hydrogenating alkenes.
Cyclic alkanes are structural isomers of alkenes.
Alkenes undergo addition reactions.
Alkanes are more reactive than alkenes.
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Question 6
Which of the following compounds does not contain a C=O bond?
aldehydes
amides
ketones
esters
ethers
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Question 7
What would be the missing reagants (reaction conditions in brackets)?
H2O
H2O (H2SO4)
HBr
Cl2
H2 and (Ni, 500 degrees)
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Question 8
Which of the following is false about aromatic compounds?
They undergo electrophilic aromatic substitution reactions.
They have delocalised pi bonds across the aromatic system.
All bond lengths in benzene are the same.
They undergo addition reactions across the double bonds.
All bond strengths in graphite are the same.
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Question 9
The molecular geometry of each carbon atom in an alkane is __________.
octahedral
square planar
trigonal planar
tetrahedral
trigonal pyramidal
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Question 10
The compound above is an __________.
alkyne
alkene
alkane
aromatic compound
olefin
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Question 11
Which substance would be the most soluble in gasoline?
water
NaNO3
HCl
hexane
NaCl
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Question 12
The addition of HBr to 2-butene produces __________.
1-bromobutane
2-bromobutane
1,2-dibromobutane
2,3-dibromobutane
no reaction
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Question 13
The general formula for an ether is __________.
R-O-R'
R-CO-R'
R-CO-OH
R-OH
RCO-H
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Question 14
The general formula of an ester is __________.
R-O-R'
R-CO-O-R'
R-CO-OH
R-OH
RCO-H
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Question 15
How many isomers of C2H2Cl2 have a net dipole moment?
none
1
2
3
It is impossible to tell without more information
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Quiz 2
Quiz Results
Question 1
Which of the above contains an amide linkage between R and R'?
A
B
C
D
E
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Question 2
Which of the above molecules is chiral?
A
B
C
D
E
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Question 3
How many chiral centers are there in CH3CHClCH2CH2CHBrCH3?
0
1
2
3
4
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Question 4
Which of the above could be formed by oxidation [O] of a secondary alcohol?
A
B
C
D
E
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Question 5
Which of the above is an ether?
A
B
C
D
E
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Question 6
Which two of the above could be reacted together to make an amide?
A and C
B and D
C and E
B and E
A and D
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Question 7
Which of the above can be formed by reaction of ethyl benzoate and water in the presence of an acid ?
A
B
C
D
E
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Question 8
The two compounds shown above are
optical isomers
enantiomers
diasteriomers
the same
A and B mean the same thing
B and C mean the same thing
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Question 9
What would be the best way to describe the above compounds?
They are diasteriomers with configurations R for compound A and S for compound B
They are the same compound
They are enantiomers with configurations R for compound A and S for compound B
They are optical isomers with configurations S for compound A and R for compound B
They are meso compounds
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Question 10
How would you match the 4 monomers above with the 4 resulting addition polymers?
A=1, B=2, C=3, D=4
A=2, B=3, C=1, D=4
A=3, B=1, C=4, D=2
A=3, B=2, C=4, D=1
A=4, B=2, C=3, D=1
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Question 11
Which of the five molecules is an isomer of compound 1 shown above.
A
B
C
D
E
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Question 12
What type of isomerisation was shown in the previous question
conformational
geometric
optical
structural
diastereoisomers
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Question 13
What type of alcohol is depicted?
primary alcohol
secondary alcohol
tertiary alcohol
quaternary alcohol
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Question 14
When drawing a mechanism using curved arrows to depict electron movement, the arrows will always go from
a region of high electron density to a region of low electron density.
from a positive charge to a negative charge
from a base to an acid
from the more reactive molecule to the less reactive molecule
from the reactant to the product
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Question 15
Which of the following is false about functional groups?
Carboxylic acids are rigid and planar due to the resonance contribution of double bonds to both oxygens.
Oxidation of a secondary alcohol gives a ketone.
An aldehyde can be oxidised to a carboxylic acid.
They tend to be electron poor.
The reaction of an ester to form a carboxylic acid will also produce an alcohol.
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Quiz 3
Quiz Results
Question 1
Which of the following would not affect the rate of a chemical reaction?
The temperature of the reaction.
The addition of a catalyst.
The concentration of reactants
Whether the reactants are in solid or liquid phase
The size of the erlenmeyer flask the reaction is run in.
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Question 2
What is an example of using a change in concentration to increase the rate of a reaction?
Milk spoils faster when left on the counter than when stored in the fridge.
Sulphuric acid readily dissolves a metal container that could hold acetic acid for months.
The addition of a catalytic convertor decreases the amount of CO that is in the car exhaust.
An aluminium bikeframe does not rust whereas an iron bikeframe rusts readily.
An epipen is used to inject medicine directly into the bloodstream to stave off a potentially fatal allergic reaction.
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Question 3
Consider the following reaction: 3A-->2B. The average rate of appearance of B is given by Δ [B]/Δ t. Comparing the rat
the rate of disappearance of A, we get Δ B/Δ t =
×(Δ [A]/Δ t
"-2/3"
"+2/3"
"-3/2"
"1"
"3/2"
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Question 4
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) --> B(g). The above
the reaction proceeds. These data will be used to answer this question and the next two questions. The average rate of di
10 s and 20 s is __________ mol/s
2.2*10-3
1.1*10-3
4.4*10-3
454
8.8*10-4
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Question 5
For the above reaction of A(g) --> B(g), what is the average rate of disapearance of A over the 40 s of the reaction?
1.75*10-3
0.054
3.1*10-3
0.124
1.35*10-3
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Question 6
For the above reaction of A(g) --> B(g), how many moles of B are present after the reaction has proceeded for 10 sec? A
present.
0.011
0.028
0.014
0.054
0.124
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Question 7
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) --> 2B(g). The above
as the reaction proceeds. These data will be used to answer this question and the next question. The average rate of appe
and 20 s is __________ mol/s
2.2*10-3
1.1*10-3
4.4*10-3
454
8.8*10-4
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Question 8
For the above reaction of A(g) --> 2B(g), how many moles of B are present after the reaction has proceeded for 10 sec?
present
0.011
0.028
0.014
0.054
0.124
B and C
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Question 9
The peroxydisulfate ion reacts with the iodide ion in aqueous solution via the above reaction. An aqueous solution containi
and 0.072 M of I- is prepared, and the progress of the reaction followed by measuring [I- ]. The data obtained is given in
will be used to answer this question and the next question. The average rate of disapearance of I- between 400.0 s and 8
moles/s.
2.8*10-5
9.2*10-6
5.8*10-5
3.6*10^4
2.6*10-4
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Question 10
Using the reaction and data table from the previous question, the average rate of disapearance of S2O8
moles/s.
2.8*10-5
9.2*10-6
5.8*10-5
2-
between 400.0 s
3.6*10^4
2.6*10-4
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Question 11
A reaction was found to be second order in carbon monoxide concentration. The rate of the reaction __________ if the co
doubled, with everything else kept the same.
doubles
remains unchanged
triples
increases by a factor of 4
is reduced by a factor of 2
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Question 12
The experimentally determined rate law for the reaction 2 NO(g) +2H2(g) --> N2(g) +2 H2O is : rate= [NO]2[H2]. What ar
rate law?
1st order in NO, 2nd order in H2, 2nd order overall
2nd order in NO, 1st order in H2, 2nd order overall
2nd order in NO, 2nd order in H2, 3rd order overall
2nd order in NO, 1st order in H2, 3rd order overall
1st order in NO, 1nd order in H2, 2nd order overall
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Question 13
The experimentally determined rate law for the reaction 2 NO(g) +2H2(g) --> N2(g) +2 H2O is : rate= [NO]2[H2]. If the NO
and the H2 concentration is held the same what happens to the rate?
No change
Doubles
Triples
Increases by a factor of 4
Increases by a factor of 10
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Question 14
The experimentally determined rate law for the reaction 2 NO(g) +2H2(g) --> N2(g) +2 H2O is : rate= [NO]2[H2]. If the H2
and the NO concentration is held the same what happens to the rate?
No change
Doubles
Triples
Increases by a factor of 4
Increases by a factor of 10
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Question 15
How could one increase the rate of a gas phase reaction? Assume the number of moles of initial reactants is constant and
constant temperature in the absense of a catalyst and with no change in state.
Increase the size of the reaction vessel thereby increasing the pressure and increasing the reaction rate.
Decrease the size of the reaction vessel thereby increasing the pressure and increasing the reaction rate.
Increase the size of the reaction vessel thereby decreasing the pressure and increasing the reaction rate.
Decrease the size of the reaction vessel thereby decreasing the pressure and increasing the reaction rate.
There is no way to affect the rate of the reaction.
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Quiz 4
Quiz Results
Question 1
For a reaction of the type A + B + C going to products, the following observations are made:
Doubling the concentration of A doubles the rate, doubling the concentration of B has no effect on
the rate, and tripling the concentration of C increases the rate by a factor of 9. What is the rate law
for the reaction?
rate = k[A]2[B][C]2
rate = k[A][C]2
rate = k[A]2[B][C]
rate = k[A][B][C]
rate = k[A]2[C]
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Question 2
The following data were collected for the rate of disappearance of NO in the reaction: 2NO(g) + O2
(g) --> 2NO2, What is the rate law for the reaction and the value of the rate constant?
rate = k[NO]2[O2], k = 7.11 x 103 M -2 s-1
rate = k[NO][O2]2, k = 7.16 x 103 M -2 s-1
rate = k[O2], k = 1.12 M-2 s-1
rate = k[NO]2, k = 8.88 x 101 M-1 s-1
rate = k[NO][O2], k = 8.95 x 101 M-1 s-1
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Question 3
Which concentration plot is linear for a first-order equation? (A is one of the reactants.)
1/[A] versus time
square root of [A] versus time
[A]2 versus time
ln[A] versus time
[A] versus time
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Question 4
In a second-order reaction the rate constant is 4.00 x 10-4 M-1 s-1. What is the concentration of
reactant after 10 min if the initial concentration is 0.800 M?
0.629 M
0.300 M
0.797 M
1.49 M
0.671 M
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Question 5
The thermal decomposition of N2O5(g) to form NO2(g) and O2(g) is a first-order reaction. The rate
constant for the reaction is 5.1 x 10-4 s-1 at 318 K. What is the half-life of this process?
3.9 x 103 s
2.0 x 103 s
1.4 x 103 s
2.6 x 10-4 s
1.0 x 10-3 s
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Question 6
As the temperature of a reaction in solution is increased, the rate of the reaction increases because
the
reactant molecules collide less frequently.
reactant molecules collide with greater energy.
activation energy is lowered.
reactant molecules collide less frequently with a lower energy.
reactant molecules collide less frequently and with greater energy.
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Question 7
In a series of reactions, which is the rate-determining step?
the slowest reaction
the reaction with the highest order
the simplest reaction
the fastest reaction
the main reaction involving the major reactant
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Question 8
Write a rate law for the following elementary reaction: NO + Cl2 --> NOCl2 and determine the
molecularity of the elementary reaction.
rate = k[NO][Cl2]2; bimolecular
rate = k[NO][Cl2]; bimolecular
rate = k[NO]2[Cl2]; termolecular
rate = k[NO][Cl2]; unimolecular
rate = k[NO][Cl2]2; termolecular
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Question 9
Which one of the following statements is incorrect?
Heterogeneous catalysts are often found on a solid in contact with gaseous reactants.
Catalysts speed up a reaction by lowering the activation energy.
An automotive catalytic converter uses a catalyst to burn gasoline better for higher gas
mileage.
Homogeneous catalysts are present in the phase where the reactions take place.
Enzymes are biological catalysts.
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Question 10
The proper expression for Kc for the reaction
NiCO3(s) + 2H+(aq) --> Ni2+(aq) + CO2(g) + H2O(l) is
[NiCO3]/[Ni2+].
[CO2]
[Ni2+]/[H+]2
[Ni2+]/[NiCO3]
[Ni2+][CO2]/[H+]2.
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Question 11
Calculate the equilibrium constant for the reaction: 2SO3(g) --> 2SO2(g) + O2(g) if a 3.25-L tank is
found to contain 0.343 atm O2, 0.0212 atm SO3, and 0.00419 atm SO2 at equilibrium.
6.79 x 10-3
4.12 x 10-3
2.43 x 102
1.34 x 10-2
8.78
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Question 12
In which of the following elementary processes is the molecularity unimolecular?
(i) N2O(g) + Cl(g) --> N2(g) + ClO(g)
(ii) Cl2(g) --> 2Cl(g)
(iii) NO(g) + Cl2(g)--> NOCl2(g)
i only
ii and iii only
i and iii only
iii only
ii only
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Question 13
The following mechanism has been proposed for the reaction of NO with H2:
NO + NO --> N2O2
N2O2 + H2 --> N2O + H2O.
If the observed rate law is rate = k[NO]2[H2], what can be concluded about the relative speeds of
the first and second steps?
The first step is slower than the second step.
The first step is faster than the second step.
The rates are about the same.
Nothing can be determined.
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Question 14
Given the following mechanism for the formation of XO2, which species is a catalyst?
X + YO2 --> XO + YO
XO + YO2 --> XO2 + YO
YO + O2 --> YO2 + O
YO + O --> YO2
XO
XO2
X
YO2
O2
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Question 15
Given the following mechanism, what is the overall balanced equation?
X + YO2 --> XO + YO
XO + YO2 --> XO2 + YO
YO + O2 --> YO2 + O
YO + O --> YO2
X+YO --> YO +XO
YO + O --> YO2
X+O2-->XO2
2X+2YO2 +O2 -->2YO +2XO2
X + 2YO + 2O2 --> 2YO2 +XO2
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Quiz 5
Quiz Results
Question 1
A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction
2A(g) --> 3B(g). The above data are obtained for [A] as the reaction proceeds. The average rate of
appearance of B between 20 s and 30 s is __________ mol/s
0.015 Ms-1
0.030 Ms-1
0.045 Ms-1
0.0225 Ms-1
"-0.015 Ms-1"
"-0.030 Ms-1"
"-0.045 Ms-1"
"-0.0225 Ms-1"
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Consider the stoichiometry
Question 2
From the following graph, calculate the average rate of reaction between t=0 and 300 seconds and
the instanteous rate at t=0 seconds.
1.83E-4, 3.0E-4
1.83E-4, 1.65E-4
1.83E-4, 2.0E-4
1.50E-4, 3.0E-4
1.5E-4, 2.0E-4
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Question 3
For a first order reaction 3A --> B, the initial concentration of A was 6.00 M. After 400 s, the
concentration of B was 1.25 M. What is the value of the rate constant (in s-1)?
1.53E-03
9.38E-03
1.18E-03
3.92E-03
3.13E-03
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Question 4
For this question, please write the integrated rate laws and sketch the graphs that give a straight
line with a slope of k or -k for a zeroth, first, second reaction. Try to do this without using your
notes. Then match the following values to their descriptions.
1. y axis of zeroth order graph
__4__ 1/[A]o
__2__ ln [A]
2. y axis of first order graph
__6__ k
3. x axis of second order graph
__1__ [A]
4. y intercept of second order graph
__3__ time
5. slope of first order graph
__5__ "-k"
6. slope of second order graph
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Question 5
For the hypothetical gas-phase reaction 3A(g) --> 2B(g), the number of moles of A present at 25
min is found to be 0.022. If the initial number of moles of A and B were 0.050 mol and 0.00 mol,
respectively, how much B is present at 25 min?
0.056 mol
0.019 mol
0.022 mol
0.028 mol
0.0093 mol
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Question 6
Consider the combustion of hydrogen: 2H2(g) + O2(g) --> 2 H2O. If hydrogen is burning at the rate
of 4.6 mol s-1, what are the rates of consumption of oxygen and formation of water vapour?
4.6 mol s-1 (O2) and 4.6 mol s-1 (H2O)
-4.6 mol s-1 (O2) and +4.6 mol s-1 (H2O)
"-2.3 mol s-1 (O2) and 2.3 mol s-1 (H2O)"
-2.3 mol s-1 (O2) and -4.6 mol s-1 (H2O)
2.3 mol s-1 (O2) and 4.6 mol s-1 (H2O)
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This question tests the stoichiometry of reactions and relative rates. For additional information read pag
If the reaction 2A + 3D products is first-order in A and second-order in D, then the rate law will
have the form:
k[A]2[D]2
k[A]2[D]
k[A]2[D]3
k[A][D]2
k[A][D]
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Section 12.3 of the textbook covers reactions orders. Sample exercise 12.6 is also very useful for deter
Question 8
The proper expression for Kc for the reaction
2HF(aq) + C2O42-(aq) --> 2F-(aq) + H2 C2O4(aq) is
[HF]2 [C2O42-] / [F-]2[H2C2O4]
2[HF] [C2O42-] /2 [F-][H2C2O4]
2 [F-][H2 C2O4]/2[HF] [C2O42-]
[F-]2[H2 C2O4]/[HF]2 [C2O42-]
[F-][H2C2O4]/[HF] [C2O42-]
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See section 13.2 and section 13.3. Question 13.12 has some examples (but also includes heterogeneou
on 9
Calculate the equilibrium constant for the reaction: 2SO3(g) --> 2SO2(g) + O2(g) if a 3.25-L tank is
found to contain 0.343 atm O2, 0.0212 atm SO3, and 0.00419 atm SO2 at equilibrium.
6.79 x 10-3
4.12 x 10-3
2.43 x 102
1.34 x 10-2
8.78
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Quiz 6
Quiz Results
Question 1
Which of the following quantities: heat, work, enthalpy, internal energy are state functions,( that is
they depend only on the end points and not on the path followed in a process)?
enthalpy and internal energy
enthalpy
heat
work
internal energy
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Question 2
For a process in which the internal energy (U) does not change , which of the following are possible?
(i) heat > 0, work < 0 (ii) heat > 0, work > 0 , (iii) heat < 0, work < 0 , (iv) heat < 0, work > 0
i and ii
i and iv
ii and iii
ii and iv
iii and iv
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Question 3
When 0.430 mol NH3 is formed from nitrogen and hydrogen, 18.38 kJ of energy is released as heat.
Assuming constant pressure is maintained, what is the H for this reaction per mole of NH3 formed?
42.7 kJ
"-42.7 kJ"
18.4 kJ
0.024 kJ
"-0.024kJ"
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Question 4
Consider the following reaction:
2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(g) H = -2511 kJ
Calculate the amount of heat transferred when 2.60 g of C2H2(g) is consumed in this reaction at
constant pressure.
-6.53 x 103 kJ
-502 kJ
"-126 kJ"
-3.26 x 103 kJ
-251 kJ
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Question 5
When heat is absorbed by the system from the surroundings, the process is said to be
____________, and the sign of q is ___________.
exothermic, positive
exothermic, negative
endothermic, negative
endothermic, positive
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Question 6
An endothermic reaction is carried out in a coffee-cup calorimeter. Which statement is incorrect for
this process?
The temperature of the water decreases
The products have higher enthalpy than the reactants
Heat is absorbed from the water.
The enthalpy change for the reaction is positive.
The enthalpy change for the reaction is equal to qH2O
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Question 7
The fuel used in spacecraft must contain as much energy per gram of material as possible. Based on
this consideration only, which of the following fuels is best suited to be a spacecraft fuel?
(i) dimethylhydrazine, (CH3)2NNH2 H combustion = -1694 kJ/mol
(ii) methanol, CH3OH Hcombustion = -726 kJ/mol
(iii) ethanol, C2H5OH Hcombustion = -1371 kJ/mol
(iv) octane, C8H18 Hcombustion = -5500 kJ/mol
(v) ethylene glycol, C2H6O2 Hcombustion = -1190 kJ/mol
octane
ethanol
ethylene glycol
dimethylhydrazine
methanol
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Question 8
Calculate the change in internal energy (delta U) for a system undergoing an endothermic process
in which 15.6 kJ of heat flows and where 1.4 kJ of work is done on the system.
17 kJ
"-17 kJ"
14.2 kJ
"-14.2 kJ"
15.6 kJ
"-15.6 kJ"
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Question 9
Calculate the work done with the expansion of gas from 46 m3 to 64 m3 at a constant external
pressure of 15 Pa.
960
690
"-960"
270 J
"-270 J"
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Question 10
When 1.00 L of 1.00 M Ba(NO3)2 solution at 25 C is added to 1.00 L of 1.00 M Na2SO4 solution at
25 C in a calorimter, the white solid BaSO4 forms and the temperature of the mixture increses to
28.1 C. Assuming the calorimeter absorbs only a negligable quantity of heat, that the specific heat
capacity of the solution is 4.18 J/gK and the density of the final solution is 1.0 g/mL, calculate the
enthalpy change per mole of BaSO4 formed.
"-260 kJ/mol"
"-26, 000 kJ/mol"
"-26 kJ/mol"
"130 kJ/mol"
"13 kJ/mol"
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Question 11
Which of the following is not a way of stating the first law of thermodynamics.
The energy of the universe is constant.
If heat is lost by the system, it must be gained by the surroundings
Energy cannot be created or destroyed, it can only change its form.
If work is done on the system during an exothermic reaction then the energy of the system
must increase.
Energy lost by the surroundings must be gained by the system
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Question 12
Choose the scenario where q<0, w>0 and delta U is <0
A reaction attached to a piston pushes up on the piston and moves it for 70 kJ of work and
the system cools down absorbing 30 kJ of heat from its surroundings.
A reaction attached to a piston pushes up on the piston and moves it for 14 kJ of work and
the system releases 30 kJ of heat to the surroundings.
A piston pushes down on a reaction decreasing the volume inside the reaction vessel for 15
kJ of work and 10 kJ of heat is released by the system.
A reaction attached to a piston pushes up on the piston and moves it for 14 kJ of work and
the system cools down absorbing 30 kJ of heat from its surroundings.
A battery is attached to a reaction vessel and does electrical work (10 kJ) on the system
which then undergoes a 50 kJ exothermic reaction.
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Question 13
Why is the q of an exothermic reaction considered to be negative when so much heat is released?
Because we calculate the energy of the reaction from the point of view of the system not
the surroundings.
Because we calculate the energy of the reaction from the point of view of the system not
the surroundings.
Because we calculate the energy of the reaction from the point of view of the system not
the surroundings.
Because we calculate the energy of the reaction from the point of view of the system not
the surroundings.
The fact that we calculate the energy of reactions in thermodynamic questions from the
point of view of the system, not the surroundings may be an important concept. When a
reaction explodes, consider what happens to the system, not your own eyebrows.
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Question 14
What is the kinetic energy of 0.33 moles of H2 molecules moving with an average speed of 4000
km/hr?
733 J
814 kJ
407 J
814 J
3200 kJ
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Question 15
Given the thermochemical equation 2NO(g) + O2(g) 2NO2(g) H = -114.0 kJ, calculate H for the
following reaction: NO2(g) NO(g) + 1/2O2(g). Is it exothermic or endothermic?
114 kJ, exothermic
"-114 kJ", exothermic
"-114 kJ", endothermic
57 kJ, endothermic
57 kJ exothermic
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Quiz 7
Quiz Results
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Question 1
Determine the value of H° in kJ for the following reaction: 2SO2(g) + O2(g) --> 2SO3(g)
"-198 kJ"
198 kJ
99 kJ
"-99 kJ"
"-357"
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Question 2
Use the following thermochemical equations
C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O(l) H= -1367 kJ
H2(g) + 1/2O2(g) --> H2O(l) H = -286 kJ
C(graphite) + O2(g) --> CO2(g) H= -394 kJ
to calculate the standard enthalpy of formation for the following reaction:
2C(g) + 3H2(g) + 1/2O2(g) --> C2H5OH(l)
+279 kJ/mol
+687 kJ/mol
+680 kJ/mol
-279 kJ/mol
+2047 kJ/mol
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Question 3
Which of these samples of gas has the highest entropy?
2 mol of methane gas occupying 2 L
1 mol of methane gas occupying 1 L
Each of these samples has the same amount of entropy because they are at the same
pressure.
1 mol of ethane gas occupying 1 L
2 mol of ethane gas occupying 2 L
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Question 4
Calculate The delta H for the syntheis of diborane (B2H6) from its elements using the following
data:
2B(s) + 3/2O2(g) --> B2O3(s) -1273 kJ
B2H6(g) +3O2(g) -->B2O3(s) + 3H2O(g) -2035 kJ
H2(g) +1/2O2(g) --> H2O(l) -286 kJ
H2O(l) --> H2O(g) 44 kJ.
36 kJ
14 kJ
378 kJ
-378 kJ
760 kJ
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Question 5
Considering the equation ΔG = ΔH -TΔS, in which scenario MUST the reaction be spontaneous? All
scenarios describe only the system.
Entropy decreases and enthalpy increases
Entropy increases and enthalpy increases
Entropy increases and enthalpy decreases
Entropy decreases and enthalpy decreases
Entropy and Enthalpy remain constant
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Question 6
Which of the following is NOT true about a spontaneous process?
The free energy of the reaction is less than zero
The entropy of the universe increaeses
The reaction is exothermic
The reverse reaction is always non spontaneous under the same reaction conditions
Whether a reaction is spontaneous can be changed by altering reaction conditions.
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Question 7
In the metallurgy of antimony, the pure metal is recovered via different reactions, depending on the
composition of the ore.
For example, iron is used to reduce antimony in sulphide ores:
Sb2S3(s) +Fe(s) --> 2 Sb(s) +3FeS(s) Δ H = -125 kJ, What is the Δ S(surroundings) for this
reaction at 25° C and 1 atm?
419 J/K
"-419 J/K"
5 J/K
"-5 J/K"
125 kJ
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Question 8
In the metallurgy of antimony, the pure metal is recovered via different reactions, depending on the
composition of the ore.
For example, carbon is used to reduce antimony in oxide ores:
Sb4O6(s) +6C(s) --> 4Sb(s) +CO(g) Δ H = 778 kJ What is the Δ S(surroundings) for this reaction
at 25 °C and 1 atm?
31.2 kJ/K
-31.2 kJ/K
-778 kJ
-2.61 kJ/K
2.61 kJ/K
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Question 9
Methanol is a fuel used in racing car engines and fuel cells. Calculate Δ G for the reaction
2CH3OH(l) + 3O2(g) --> 2CO2 (g) + 4H2O(g)
using the following free energies of formation :
CH3OH(l) -163 kJ/mol
CO2 (g) -394 kJ/mol
O2(g) 0 kJ/mol
H2O(g) -229 kJ/mol.
-1378 kJ
- 460kJ
-1500 kJ
-765 kJ
-980 kJ
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Question 10
In which case does the entropy of the system decrease significantly?
C(s) + O2(g) --> CO2(g)
N2(g) + 3H2(g) --> 2NH3(g)
CaCO3(s) --> CaO(s) + CO2(g)
H2O(l) --> H2O(g)
SnO2(s) + 4C(s) --> Sn(s) + 4CO2(g)
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Question 11
Some standard entropies (at 25°C in J/mol K) are given in the following list: diamond 2.43, O2(g)
205.0, CO(g) 197.9. The value of S° for the reaction:
2C(diamond) + O2(g) -->
2CO(g) at 25°C in J/K is
-9.5 J K-1
390.9 J K-1
-185.9 J K-1
+185.9 J K-1
+9.5 J K-1
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Question 12
Calculate G° in kJ at 350°C for the reaction:
2NO2(g) --> N2O4(g)
For NO2(g) Hf° = 33.18 kJ/mol and S°= 240.1 J/molK For N2O4(g) Hf° = 9.16 kJ/mol and S° =
304.3 J/molK
-413 kJ
-64.0 kJ
52.4 kJ
4.37 kJ
1.10 x 105 kJ
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Question 13
Calculate S in J/K for the reaction:
C(s) + O2(g) --> CO2(g)
S° J/molK = 5.69 for C(s), 205 for O2(g) and 213.6 for CO2(g)
-424.3 J/K
424.3 J/K
2.9 J/K
-2.9 J/K
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Question 14
Choose the scenario where q>0, w<0 and ΔU <0
A reaction attached to a piston pushes up on the piston and moves it for 70 kJ of work and
the system cools down absorbing 30 kJ of heat from its surroundings
A reaction attached to a piston pushes up on the piston and moves it for 14 kJ of work and
the system releases 30 kJ of heat to the surroundings.
A piston pushes down on a reaction decreasing the volume inside the reaction vessel for 15
kJ of work and 10 kJ of heat is released by the system
A reaction attached to a piston pushes up on the piston and moves it for 14 kJ of work and
the system cools down absorbing 30 kJ of heat from its surroundings.
A battery is attached to a reaction vessel and does electrical work (10 kJ) on the system
which then undergoes a 50 kJ exothermic reaction.
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Question 15
Which of the following processes are spontaneous and which are nonspontaneous: (i) separation of
gaseous N2 and O2 molecules from each other, (ii) the reaction of sodium metal with chlorine gas
to form sodium chloride, (iii) the dissolution of HCl(g) in water to form concentrated hydrochloric
acid?
(i) nonspontaneous (ii) spontaneous , (iii) spontaneous
(i) nonspontaneous (ii) nonspontaneous , (iii) spontaneous
(i) spontaneous (ii) spontaneous , (iii) spontaneous
(i) nonspontaneous (ii) spontaneous , (iii) nonspontaneous
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Quiz 8
Quiz Results
Question 1
Designate the conjugate Br�nsted-Lowry acid for each of the following bases: (i) NH3 (ii) CN- (iii)
NH2NH4+, H2CN, NH3
NH4+, HCN, NH3
NH3, H2CN, NH3
NH2-, HCN, NH4+
NH3, HCN, NH3
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Question 2
What is the concentration of hydronium ions in a solution with a hydroxide-ion concentration of 2.31
x 10-4 M at 25�C?
4.33 x 10-11 M
2.31 x 10-4 M
2.31 x 10-18 M
2.31 x 1010 M
1.8 M
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Question 3
Calculate the pH of a solution if its [OH-] = 0.0000700 M and indicate whether the solution is acidic,
basic, or neutral.
9.8, acidic
11, basic
2.15, acidic
9.8, basic
17.2, basic
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Question 4
Which one of the following 0.1 M solutions would have a pH of 7.0?
NH4Cl
Cu(CH3COO)2
NaF
NaNO3
Na2S
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Question 5
If the pH of a solution is 6.30, what are the molar concentrations of H+(aq) and OH-(aq) at 25�C?
5.0 x 10-7 M and 1.0 x 10-7 M
1 x 10-7 M and 6.3 x 10-7 M
5.0 x 10-7 M and 5.0 x 10-7 M
6.3 x 10-7 M and 1.0 x 10-7 M
5.0 x 10-7 M and 2.0 x 10-8 M
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Question 6
Which of the following acids, if in solutions of equal concentration, is the most acidic?
boric acid, Ka = 5.8 x 10-10
HF, Ka = 6.3 x 10-4
lactic acid, Ka = 1.4 x 10-4
acetic acid, Ka = 1.8 x 10-5
All of these acids are equally acidic because they are all of equal concentration.
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Question 7
Lactic acid, HC3H5O3, has one acidic hydrogen. A 0.10 M solution of lactic acid is measured with a
pH of 2.44. Calculate Ka based on this data.
3.6 x 10-3
1.3 x 10-4
1.3 x 10-5
1.4 x 10-4
1.0 x 10-3
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Question 8
Calculate the pH of the following strong acid solution: 2.02 g of HNO3 in 400 mL of solution
4
1.7
2.3
1.5
1.1
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Question 9
Which of the following statements is false?
A Lewis acid does not have to contain a proton.
An Arrhenius acid is a proton acceptor
Metal ions show acidic properties.
A Lewis base is an electron pair donor.
Salts dissolve in water due to the attraction of the positive ions for water molecules.
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Question 10
Given the following Ka values, HC2H3O2 Ka = 1.8 x 10-5
HClO3 Ka = 5.0 x 10^2
HCN Ka = 4.9 x 10-10
HF Ka = 6.8 x 10-4
HOCl Ka = 3.0 x 10-8
Which is the weakest base?
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