Quiz  /  Bond Energy Class 9 MCQ Questions With Answers

  • 1. 
    What kind of energy is stored in the chemical bonds between atoms?

  • kinetic energy
  • thermal energy
  • chemical energy
  • light energy

  • 2. 
    Is this equation endo- or exo-thermic?2KNO3 (s) + energy --> 2KNO2 (s) + O2

  • endothermic
  • exothermic

  • 3. 
    How many valence electrons does sulfur (S) have?

  • 3
  • 4
  • 5
  • 6

  • 4. 
    All types of chemical bonds hold the same amount of chemical energy.

  • True
  • False

  • 5. 
    How many types of bonds are present in this molecule?

  • 3
  • 5
  • 6
  • 8

  • 6. 
    Using the table of average bond energies below the image, the ΔH for the reaction in kJ is.....

  • + 160 kJ
  • -63 kJ
  • - 160 kJ
  • -217 kJ

  • 7. 
    Valence electrons in pairs (as shown here on the nitrogen) are able to be used for additional bonding.

  • True
  • False

  • 8. 
    Which units are used to measure energy?

  • Newtons
  • kilograms
  • meters/second
  • Joules

  • 9. 
    Which is an example of an endothermic physical reaction?

  • a) Ice melting
  • b) Combustion
  • c) Steam condensing
  • d) Photosynthesis

  • 10. 
    The following equation shows the formation of magnesium oxide from magnesium metal. Which statement is correct for this reaction?2Mg(s) + O2(g) → 2MgO(s) ΔH = -1204 kJ

  • 1204 kJ of energy are released for every mole of magnesium reacted
  • 602 kJ of energy are absorbed for every mole of magnesium oxide formed
  • 602 kJ of energy are released for every mole of oxygen reacted
  • 1204 kJ of energy are released for every two moles of magnesium oxide formed

  • 11. 
    How can you determine an atom's valence electrons?

  • the column on the periodic table
  • the row on the periodic table
  • the atomic number
  • the atomic mass

  • 12. 
    What kind of energy change happens in the photosynthesis reaction in plant leaves?

  • Endothermic
  • Exothermic
  • No change

  • 13. 
    When the solids Ba(OH)2 and NH4SCN are mixed, a solution is produced and the temperature drops. Which statement about the energetics of this reaction is correct?

  • The reaction is endothermic and ΔH is negative
  • The reaction is endothermic and ΔH is positive
  • The reaction is exothermic and ΔH is negative
  • The reaction is exothermic and ΔH is positive

  • 14. 
    What kind of energy is released or absorbed when chemical bonds are formed and broken?

  • kinetic energy
  • thermal (heat) energy
  • chemical energy
  • light energy

  • 15. 
    For the reaction 2H2(g) + O2(g) → 2H2O(g) the bond enthalpies (in kJ/mol) are H-H = x, O=O = y, O-H = zWhich calculation will give the value, in kJ/mol, of ΔH for the reaction?

  • 2x + y - 2z
  • 4z - 2x - y
  • 2x + y - 4z
  • 2z - 2x - y

  • 16. 
    How many C-H bonds are present here?

  • 4
  • 5
  • 6
  • 7

  • 17. 
    How do atoms fill their valence level with electrons?

  • share with other atoms
  • steal from other atoms
  • give up electrons to other atoms

  • 18. 
    How many valence electrons does neon (Ne) have?

  • 6
  • 7
  • 8
  • 9

  • 19. 
    What is an electron?

  • + charged particle in an atom's nucleus
  • - charged particle in an atom's nucleus
  • - charged particle outside an atom's nucleus
  • + charged particle outside an atom's nucleus

  • 20. 
    Is this equation endo- or exo-thermic?PCl3 (s) + Cl2 (g) --> PCl5 (s) + energy

  • endothermic
  • exothermic

  • 21. 
    How many valence electrons do most electrons want in their valence shell to be stable? (Except hydrogen!)

  • 2
  • 4
  • 6
  • 8

  • 22. 
    How many electrons are shared in one chemical bond?

  • 2
  • 4
  • 6
  • 8

  • 23. 
    How can we figure out if an overall reaction is endo- or exo-thermic? It is the difference between _______ and __________.

  • hot and cold temperatures
  • energy to break and energy to form bonds.
  • time to form a bond versus time to break a bond

  • 24. 
    Which of the following is NOT a type of bond present in this molecule?

  • C-H
  • C-C
  • C=O
  • C-O

  • 25. 
    How many carbon-oxygen double bonds are present here?

  • 1
  • 2
  • 3
  • 4

  • 26. 
    Does breaking bonds require energy, release energy, or not involve energy at all?

  • requires energy to break
  • releases energy when broken
  • No energy involved
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