Quiz  /  Entropy Class 12 MCQ Questions With Answers

  • 1. 
    Is photosynthesis an exothermic or endothermic reaction?

  • Endothermic
  • Exothermic
  • Neither

  • 2. 
    Is the combustion of gasoline endothermic or exothermic?

  • Endothermic
  • Exothermic

  • 3. 
    What is the symbol for entropy?

  • H
  • G
  • S
  • E

  • 4. 
    The reaction A + 2 B2 + C --> CAB4 has an enthalpy change of -104 kJ and a change in entropy of -60.8 J/K at 30 °C. What is the free energy and spontaneity of the reaction?

  • -85.6 kJ, spontaneous
  • -18.3 kJ, not spontaneous
  • +18.3 kJ, spontaneous
  • +85.6 kJ, not spontaneous

  • 5. 
    Which represents a -ΔS?

  • ice melting
  • salt dissolving
  • water heating up
  • none of these

  • 6. 
    Reactions tend to be spontaneous if they are exothermic.

  • True
  • False

  • 7. 
    Entropy always increases when

  • enthalpy decreases.
  • temperature decreases.
  • temperature increases.
  • volume increases.

  • 8. 
    Entropy is a form of energy

  • True
  • False

  • 9. 
    The entropy will usually increase when

  • a molecule is broken into two or more smaller molecules
  • a reaction occurs that results in an increase in the number of moles of gas
  • a solid changes to a liquid
  • all of these

  • 10. 
    Ammonium nitrate dissolves in water. It is a spontaneous endothermic process because the system undergoes....

  • a decrease in enthalpy
  • an increase in entropy
  • an increase in enthalpy
  • a decrease in entropy

  • 11. 
    Which of these processes represents a decrease in entropy?

  • sublimation of CO2
  • boiling water
  • condensation of steam on cold glass
  • NaCl dissolving in water

  • 12. 
    Which of the following scenarios describes a process with a negative entropy change?

  • Building a skyscraper
  • A clean room becomes cluttered
  • An igloo melting
  • Osmosis (I hope you know your Biology!)

  • 13. 
    There is a natural tendency for energy to spread out.

  • True
  • False

  • 14. 
    Systems in nature tend to undergo changes toward

  • lower energy and less disorder
  • lower energy and more disorder
  • higher energy and less disorder
  • higher energy and more disorder

  • 15. 
    Which combination of ΔH and ΔS NEVER has a spontaneous reaction?

  • +ΔH and +ΔS
  • +ΔH and -ΔS
  • -ΔH and -ΔS
  • -ΔH and +ΔS

  • 16. 
    A reaction that absorbs energy is

  • Exothermic
  • Endothermic
  • Could be either

  • 17. 
    Spontaneous reactions are driven by

  • increasing enthalpy and increasing entropy.
  • decreasing enthalpy and decreasing entropy.
  • increasing enthalpy and decreasing entropy.
  • decreasing enthalpy and increasing entropy.

  • 18. 
    We can reverse a spontaneous process by intervening (eg applying heat, using distillation to separate mixtures).

  • True
  • False

  • 19. 
    A reaction has a positive ΔH and a positive ΔS. Which of the following is true?

  • It will be spontaneous at all temperatures.
  • It will be nonspontaneous at all temperatures.
  • It will be spontaneous at low temperatures.
  • It will be spontaneous at high temperatures.

  • 20. 
    Which state of matter has the greatest motion and least orderly arrangement?

  • solid
  • liquid
  • gas
  • aqueous

  • 21. 
    Which combination of ΔH and ΔS always has a spontaneous reaction?

  • +ΔH and +ΔS
  • +ΔH and -ΔS
  • -ΔH and -ΔS
  • -ΔH and +ΔS

  • 22. 
    Which has a +ΔS (system)?

  • AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
  • H2O(g) + CO2(g) → H2CO3(aq)
  • H2(g) + I2(g) → 2Hl(g)
  • C2H2O2(g) → 2CO(g) + H2(g)
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