Target: 10 Questions in 10 minutes

An IB Chemistry data booklet is helpful
1. Which statement about combustion reaction is NOT true?
  • A.   Combustion reaction is always exothermic.
  • B.   Combustion reaction is always a redox reaction.
  • C.   Combustion reaction always involves oxygen.
  • D.   Combustion reaction is always fast.
2. Which of the following equations represent an incomplete combustion reaction?
  • A. C + O2  → CO2
  • B. 2C4H10 + 5O2  → 8C + 10H2O
  • C. 2K + 2H2O  → 2KOH + H2
  • D. 2Mg + O2  → 2MgO

3. Which of the following statements are correct for this combustion reaction?

C2H5OH + 3O2  → 2CO2 + 3H2O

I. C2H5OH is the reducing agent
II. CO2 is oxidized in this reaction
III. O2 is reduced in this reaction
  • A. I and II only
  • B. I and III only
  • C. II and III only
  • D. I, II and III
4. Which of the following is NOT a fossil fuel?
  • A. Biofuel
  • B. Coal
  • C. Crude oil
  • D. Natural gas
5. The enthalpy change of combustion of octane is -5470 kJ mol-1. How much energy does it release per gram when the fuel is burned?
  • A.   5.47 kJ g-1
  • B.   47.9 kJ g-1
  • C.   625 kJ g-1
  • D.   4770 kJ g-1
6. Methanol has an enthalpy change of combustion of -726 kJ mol-1. What is the mass of CO2 produced per kJ of energy released by this fuel?
  • A.   0.0606g
  • B.   0.726g
  • C.   1.38g
  • D.   6.06g
7. Naphthalene, C10H8, is a flammable solid used as insecticides. When it burns, how much CO2 is produced per gram of fuel burned completely?
  • A.   0.0780 g
  • B.   0.343 g
  • C.   3.43 g
  • D.   44.0 g

8. Choose the correct statement(s) about natural gas as a fuel:

I. It is a type of renewable energy.
II. It is less difficult to store than coal and crude oil because it is a gas.
III. It is a cleaner fuel than coal and oil as it undergoes less incomplete combustion.
  • A.   II only
  • B.   III only
  • C.   I and III only
  • D.   II and III only
9. Which is the equation for the reaction happening at the anode of a direct methanol fuel cell?
  • A.   CH3OH + ${3}\over {2}$O2  → CO2 + 2H2O
  • B.   CH3OH + H2O  → CO2 + 6H+ + 6e- 
  • C.   ${3}\over {2}$O2 + 6H+ + 6e-  → 3H2O
  • D.   CH3OH + H2O  → CO2 + 3H2
10. What is the equation for the overall reaction in an alkaline hydrogen fuel cell?
  • A.   ½O2+ H2O + 2e- → 2OH-
  • B.   H2 + 2OH- → 2H2O + 2e-
  • C.   H2 + O2 → H2O2
  • D.   H2 + ½O2  →  H2O