Unit 3 Multiple Choice Questions

The molecule shown is

• an example of a biodiesel molecule.

• a fatty acid.

• a triglyceride.

• a typical component of petrodiesel.

What is the total amount of energy released, in kilojoules, when 20 g of ethanol and 20 g of butane undergo complete combustion?

• 994

• 1038

• 1586

• 2032

The products of a combustion reaction are shown below. 8CO2(g) + 10H2O(l) The reaction is

• the complete combustion of butane.

• the incomplete combustion of butane.

• the complete combustion of octane.

• the incomplete combustion of octane.

1.50 g of ethane undergoes complete combustion. What volume of CO2, in litres, is produced at SLC from this combustion?

• 1.24

• 2.48

• 4.96

• 24.8

McCain Foods has set up a plant to produce a fuel from the peel of the many thousands of potatoes they use each year. This fuel is most likely to be

• ethanol

• natural gas

• biodiesel

• petrodiesel

A sketch of a cell is provided below. In this cell,

• the reaction occurring at the cathode will be 2H2(g) + O2(g) 2H2O(l)

• the reaction occurring at the cathode will be O2(g) + 2H2O(l) + 4e- 4OH-(aq)

• the reaction occurring at the cathode will be H2(g) 2H+(aq) + 2e-

• the reaction occurring at the cathode will be O2(g) + 4H+(aq) + 4e- 2H2O(l)

The energy profile diagram for a chemical reaction is shown below. The activation energy, and the value of ΔH for the reverse reaction of the one shown will be, respectively,

• +150 kJ mol-1 and -100 kJ mol-1

• +150 kJ mol-1 and +100 kJ mol-1

• +250 kJ mol-1 and +100 kJ mol-1

• +250 kJ mol-1 and -100 kJ mol-1

Which of the following alternatives is not a balanced half equation?

• NO₂(g)    +  H₂O(l)   -->   NO₃^-(aq)   +  2H⁺(aq)    +  e^-

• SO₄^2-(aq)     +  4H⁺(aq)   +   2e^-  -->   SO₂(g)   +   2H₂O(l)

• CH₃CH₂OH(aq)    +   H₂(g)   --> CH₃COOH(aq)   +   4H⁺(aq)   +  2e^-

• NO₂(g)    +  H₂O(l)   -->   NO₃^-(aq)   +  2H⁺(aq)    +  e^-

The concentrations of the species present in an equilibrium mixture are shown on the graph below. A reaction that matches the concentrations shown is

• PCl₅(g) ⇋ PCl₃(g) + Cl2(g)

• H₂(g) + I₂(g) ⇋ 2HI(g)

• N₂O₄(g) ⇋ 2NO2(g)

• 2SO₂(g) + O₂(g) ⇋ 2SO₃(g)

Nitrosyl chloride can decompose to nitrogen monoxide and chlorine gas. The equation for the reaction is 2NOCl(g) ⇋ 2NO(g) + Cl₂(g) 1.8 mole of NOCl is added to an empty reactor. When equilibrium is reached, the amount of NOCl has dropped to 1.2 mole. The total number of mole of substances in the reactor at equilibrium will be

• 1.8

• 2.1

• 2.7

• 3.6