WorksheetsCOTW6
Total questions: 6
Worksheet time: 2hrs 30mins
Name
Class
Date
1.
Methylamine acts as a weak base when it reacts with water. For a diluted aqueous solution, what is the Kb expression for this reaction?
a)
Kb = [CH3NH3+][OH-] / [CH3NH2]
b)
Kb = [CH3NH2][H2O] / [CH3NH3+] [OH-]
c)
Kb = [CH3NH3+] [OH-] / [CH3NH2][H2O]
d)
Kb = [CH3NH2] / [CH3NH3+] [OH-]
2.
A buffer solution is formed by mixing equal volumes of 1.00 mol dm-3 propanoic acid and 0.500 mol dm-3 potassium propanoate. What is the concentration, in mol dm-3, of [H+(aq)] in this buffer solution? (Ka for propanoic acid is 1.30 x 10-5.)
a)
2.60 x 10-5
b)
1.9 x 10-5
c)
1.30 x 10-5
d)
0.650 x 10-5
3.
The acid-base indicator phenol red, HIn, changes colour from yellow to red over a pH range of 6.6 - 8.2. Which statement is correct?
a)
In a strongly acidic solution [HIn] < [In-].
b)
The pKa of a phenol red is between 6.6 and 8.2.
c)
The In- ions are yellow.
d)
Phenol red would be a suitable indicator for the titration of a strong acid and a weak base.
4.
In an experiment to determine a specific quantity, a student calculated that her experimental uncertainty was 0.9 % and her experimental error was 3.5%. Which statement is correct?
a)
Only random uncertainties are present in this experiment.
b)
Both random uncertainties and systematic errors are present in this experiment.
c)
Repeats of this experiment would reduce systematic errors.
d)
Repeats of this experiment would reduce both systematic errors and random uncertainties.
5.
Under which conditions does CH4 have the same number of molecules as 100 cm3 of O2 at 27oC and 1.0 x 105 Pa?
a)
volume = 50 cm3
temperature = 54oC
pressure = 1.0 x 105 Pa
temperature = 54oC
pressure = 1.0 x 105 Pa
b)
volume = 50 cm3
temperature = 327oC
pressure = 1.0 x 105 Pa
temperature = 327oC
pressure = 1.0 x 105 Pa
c)
volume = 100 cm3
temperature = 54oC
pressure = 2.0 x 105 Pa
temperature = 54oC
pressure = 2.0 x 105 Pa
d)
volume = 100 cm3
temperature = 327oC
pressure = 2.0 x 105 Pa
temperature = 327oC
pressure = 2.0 x 105 Pa
6.
THIS IS A FREE RESPONSE, NOT MULTIPLE CHOICE! So answer all the questions.
The Contact process involves an exothermic reversible reaction.
2SO2(g) + O2(g) <--> 2SO3(g) Kc >> 1 at 200oC and 1 atm
a) Deduce the extent of the reaction at 200oC and 1 atom.
b) An engineer at a Contact process plant hypothesized that using pure oxygen instead of air, would increase the profits. Comment on whether or not her hypothesis is valid, giving your reasons.
a)
I have answered ALL questions a-b.
b)
I did NOT answer questions a-b.
100 %
