WorksheetsCSHS S2 Year 12 Chemistry Exam 2016 Multiple Choice
Total questions: 25
Worksheet time: 50mins
Old fashioned ‘smelling salts’ are made of ammonium carbonate crystals, which decompose in an endothermic reaction to produce the pungent-smelling ammonia gas. The decomposition equation is shown below.
(NH4)2CO3(s) ⇌ 2 NH3(g) + CO2(g) + H2O(g)
Which of the following statements regarding this equilibrium is not correct?
The reverse reaction rate would increase if the volume of the system was decreased.
The forward reaction would be favoured by having more finely divided ammonium carbonate crystals.
The reverse reaction rate would be increased on a warmer day.
More ammonia would be produced on a warmer day.
The five (5) substances named below were dissolved in water and the pH of each was determined by adding a few drops of universal indicator. For which of these substances is the observed pH unable to be explained by the Arrhenius theory of acids and bases?
(i) Hydrochloric acid, HCl
(ii) Ethanoic acid, CH3COOH
(iii) Ammonia, NH3
(iv) Calcium carbonate, CaCO3
(v) Sodium hydroxide, NaOH
(ii) and (iii)
(i) and (iv)
(iii) and (iv)
(iv) and (v)
Consider the incomplete chemical equation shown below.
Cr(s) + ClO3-(aq) + H+(aq) -> Cr3+(aq) + HClO2(aq) + H2O(l)
When this redox reaction is completed and balanced correctly (using whole numbers), the coefficient in front of H+(aq) will be;
1
3
6
9
Which of the following lists contain compounds that all have the ability to form hydrogen bonds?
all of (i), (ii), (iii), (iv) and (v)
(ii), (iii), and (iv) only
(i), (ii), (iii) and (v) only
(ii), (iv) and (v) only
Which of the following statements regarding the five compounds is not correct?
CH3CONH2 is water-soluble.
CH3COOH is miscible with CH3CH2OH.
CH3CH3 has the highest boiling point.
CH3CHO is able to form dipole-dipole forces.
The equation below shows the key step involved in the Contact process.
2 SO2(g) + O2(g) ⇌ 2 SO3(g) ΔH = -198 kJ mol-1
Which of the following sets of conditions would increase both the rate and yield of SO3(g)?
Increased Rate: High temperature Increased Yield: Low pressure
Increased Rate: High pressure Increased Yield: Low temperature
Increased Rate: Low temperature Increased Yield: High Pressure
Increased Rate: Low Pressure Increased Yield: High temperature
Considering only the information given below, which reaction is most likely to proceed quickly in the reverse direction?
ΔH (forward) = +850kJ/mol Ea(forward) = 875kJ/mol
ΔH (forward) = +120kJ/mol Ea(forward) = 645kJ/mol
ΔH (forward) = -95kJ/mol Ea(forward) = 730kJ/mol
ΔH (forward) = -545kJ/mol Ea(forward) = 90kJ/mol
Consider the information below, relating to malonic acid (C3H4O4), which is a weak, organic, diprotic acid.
C3H4O4(aq) + H2O(l) ⇌ C3H3O4-(aq) + H3O+(aq) Ka1 = 1.48 x 10-3
C3H3O4-(aq) + H2O(l) ⇌ C3H2O42-(aq) + H3O+(aq)
Ka2 = 1.10 x 10-6
Which of the following statements is true regarding diprotic acids?
They have only 2 hydrogen atoms per molecule.
They have a lower pH than monoprotic acids of the same concentration.
They are all weak acids.
The value of Ka1 is always greater than the value of Ka2.
Rank the following substances in order of increasing nitrogen oxidation number (i.e. from species with nitrogen in lowest oxidation state to highest oxidation state).
NO3- N2O HNO2 NH4+ N2
NH4+ < N2 < N2O < HNO2 < NO3-
NO3- < N2O < HNO2 < N2 < NH4+
NH4+ < HNO2 < N2 < NO3- < N2O
N2 < NH4+ < NO3- < N2O < HNO2
For which of the following organic molecules does the structural diagram match the correct IUPAC name given?
(i) only
(i) and (ii) only
(ii) only
(ii) and (iii) only
Consider 0.25 mol L-1 aqueous solutions of the following salts;
NaHSO4 K3PO4 Ca(NO3)2
Rank these three (3) solutions in order of decreasing pH (i.e. highest to lowest).
K3PO4 > Ca(NO3)2 > NaHSO4
Ca(NO3)2 > NaHSO4 > K3PO4
NaHSO4 > Ca(NO3)2 > K3PO4
NaHSO4 > K3PO4 > Ca(NO3)2
Once the system has established equilibrium, which of the following statements are correct?
(i) The total pressure inside the container will be constant.
(ii) The pressure inside the container will be higher than initially.
(iii) The colour of the gaseous mixture will be constant.
(iv) The rates of the forward and reverse reactions will be equal.
(v) The concentration of S8 and S2 will be equal.
(i), (iii), and (iv) only
(ii), (iv) and (v) only
(i), (ii), (iii) and (iv) only
(i), (ii), (iii), (iv) and (v)
Which of the following statements regarding K for this equilibrium system is correct?
At equilibrium there is a higher concentration of S8(g) present than S2(g).
If the temperature of the system was decreased the value of K would increase.
Once the system had established equilibrium, various changes were imposed on the system and the effects of these changes were predicted using Le Chatelier’s principle. Which of the following is not correct (i.e. the predicted effect on the equilibrium position does not match the imposed change stated)?
Which of the following statements are correct, regarding fuel cells in general?
(i) Fuel cells involve a redox reaction.
(ii) Fuel cells require continuous input of reactants to operate.
(iii) Fuel cells are a type of galvanic cell.
(iv) Fuel cells are a type of secondary cell.
(v) Fuel cells do not produce any sources of pollution.
(i), (ii) and (iii) only
(i), (ii) and (v) only
(ii), (iii) and (iv) only
(i), (ii), (iii) and (v) only
Which of the following statements is correct, regarding the hydrogen/oxygen fuel cell shown in the diagram above?
Reduction occurs at X.
Electrons move from Y to X.
Cations move towards Y.
The EMF of this cell under standard conditions is 1.15 volts
The hydrogencarbonate / carbonic acid buffering system in blood helps to maintain our blood at a pH of 7.4. Carbon dioxide (CO2) can be exhaled by the lungs and hydrogen ions (H+) can be excreted by the kidneys to help maintain the delicate balance of our blood chemistry. The equations for this buffer system are shown below, along with the concentration of the two main buffer components.
HCO3-(aq) + H+(aq) ⇌ H2CO3(aq) ⇌ H2O(l) + CO2(g)
0.0245 mol L-1 0.0012 mol L-1
Which of the following statements regarding this buffer system is not correct?
H2CO3/HCO3- are a conjugate acid-base pair.
The buffering capacity is greater for a rise in H+ concentration than for a fall in H+ concentration.
A rise in H+ concentration in the blood would shift the equilibrium to the right.
Increased breathing would decrease the pH of blood.
Name the polymer described in the paragraph below.
“This addition polymer is one of the most commonly used plastics and can be easily recycled. Depending on the manufacturing conditions chosen, it can be used to make plastic milk containers, cling film, toys, shopping bags or even form part of knee and hip replacement joints.”
Polyethene
Polytetrafluoroethene
Nylon
Polyethylene terephthalate
Which of the following statements is not correct, regarding the hydrolysis of ethene to produce ethanol?
An increased pressure increases the forward reaction rate.
An increased pressure increases the ethanol yield.
An increased temperature increases the forward reaction rate.
The H3PO4 catalyst increases the ethanol yield.
Which of the following statements is not correct, regarding the fermentation method of ethanol production?
It is performed at a lower temperature than the hydrolysis method.
It is performed at a lower pressure than the hydrolysis method.
It is a less sustainable method than the hydrolysis method.
The zymase enzyme provides an alternative reaction pathway with a lower activation energy.
The equation for the autoionisation of water is shown below, along with two values for Kw at two corresponding temperatures.
H2O(l) + H2O(l) ⇌ H3O+(aq) + OH-(aq)
Kw = 1.0 x 10-14 at 25 °C
Kw = 2.9 x 10-14 at 40 °C
Considering the information provided, which of the following statements is not correct?
The autoionisation of water is an endothermic process.
The concentration of H3O+ in water at 40 °C is higher than water at 25 °C.
The pH of water at 40 °C is lower than water at 25 °C.
The water at 40 °C is slightly more acidic than water at 25 °C.
Which of the following halogen displacement reactions would not occur under standard conditions?
Cl2(aq) + 2 Br-(aq) → 2 Cl-(aq) + Br2(aq)
I2(aq) + 2 Br-(aq) → 2 I-(aq) + Br2(aq)
Cl2(aq) + 2 I-(aq) → 2 Cl-(aq) + I2(aq)
Br2(aq) + 2 I-(aq) → 2 Br-(aq) + I2(aq)
A sample of ethanoic acid was placed in a beaker and several drops of universal indicator were added. To the beaker, aqueous sodium carbonate was added dropwise until it was in excess. Which of the following statements is not correct regarding the reaction that would have taken place?
A colourless, odourless gas would have been produced.
The colour of the solution would have changed from pink to green to blue.
A neutralisation reaction would have taken place.
A solid white salt would have been produced.
Consider the section of polymer shown below.
