IBSL Chemistry Topic 5 Energetics Multiple Choice Questions

29 Questions | Total Attempts: 676

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IBSL Chemistry Topic 5 Energetics Multiple Choice Questions

Questions and Answers
  • 1. 
    Which statement about this reaction is correct?
    • A. 

      26.6 KJ of energy are released for every mole of Fe reacted

    • B. 

      26.6 KJ of energy are absorbed for every mole of Fe reacted

    • C. 

      53.2 KJ of energy are released for every mole of Fe reacted

    • D. 

      13.3 KJ of energy are absorbed for every mole of Fe reacted

  • 2. 
    When solutions of HCl and NaOH are mixed the temperature increases. The reaction:
    • A. 

      Is endothermic with a positive enthalpy energy

    • B. 

      Is endothermic with a negative enthalpy energy

    • C. 

      Is exothermic with a positive enthalpy energy

    • D. 

      Is exothermic with a negative enthalpy energy

  • 3. 
    What can be deduced about the relative stability of the reactants and products and the sign of , from the enthalpy level diagram above?
    • A. 

      Products are more stable and sign of difference of enthalpy energy is negative

    • B. 

      Products are more stable and sign of difference of enthalpy energy is positive

    • C. 

      Reactants are more stable and sign of difference of enthalpy energy is negative

    • D. 

      Reactants are more stable and sign of difference of enthalpy energy is positive

  • 4. 
    For the reaction: IF
    • A. 

      The enthalpy difference for the third reaction must be negative

    • B. 

      The enthalpy difference for the third reaction must be positive and smaller than 52.3 KJ

    • C. 

      The enthalpy difference for the third reaction must be negative and larger than 52.3 KJ

    • D. 

      No conclusion can be made without the value of H and H2(g)

  • 5. 
    The enthalpy changes for two different hydrogenation reactions of Which expression represents the enthalpy change for the reaction below?
    • A. 

      DeltaH3 = deltaH1 + deltaH2

    • B. 

      DeltaH3 = deltaH1 - deltaH2

    • C. 

      DeltaH3 = deltaH2 - deltaH1

    • D. 

      DeltaH3 = - deltaH1 - deltaH2

  • 6. 
    Use the bond energies for H-H (346kJ.mol-1), Br-Br (193 Kj mol-1) and H-Br (366 KJ mol-1) to calculate (in KJ mol-1) for the reaction:
    • A. 

      263

    • B. 

      103

    • C. 

      -103

    • D. 

      -263

  • 7. 
    The average bond enthalpy for the C-H bond is 412 KJ mol-1. Which process has an enthalpy change closest to this value?
    • A. 

      CH4 (g) -> C(s) + 2 H2(g)

    • B. 

      CH4 (g) -> C(g) + 2 H2(g)

    • C. 

      CH4 (g) -> C(s) + 4 H (g)

    • D. 

      CH4 (g) -> CH3(s) + H(g)

  • 8. 
    What energy changes occur when chemical bonds are formed and broken?
    • A. 

      Energy is absorbed when bonds are formed and when they are broken

    • B. 

      Energy is released when bonds are formed and when they are broken

    • C. 

      Energy is absorbed when bonds are formed and released when they are broken

    • D. 

      Energy is released when bonds are formed and absorbed when they are broken

  • 9. 
    The temperature of a 2.0g sample of aluminium increases from 25 to 30 degrees Celsius. How many joules of heat energy were added? Specific Heat Capacity of Al= 0.90 J.g-1. K-1
    • A. 

      0.36

    • B. 

      2.3

    • C. 

      9.0

    • D. 

      11

  • 10. 
    Using the eqautions below:
    • A. 

      +910

    • B. 

      +130

    • C. 

      -130

    • D. 

      -910

  • 11. 
    • A. 

      -570

    • B. 

      -790

    • C. 

      -860

    • D. 

      -1080

  • 12. 
    The average bond enthalpies for O-O and for O=O are 146 and 496 KJ.mol-1 repectively. What is the enthalpy change, in KJ, for the reaction below? H-O-O-H (g)  --> H-O-H (g)  + 1/2 O=O (g)
    • A. 

      -102

    • B. 

      +102

    • C. 

      +350

    • D. 

      +394

  • 13. 
    The enthalpy changes for two different hydrogenation reactions of C2H2 are; C2H2 + H2 ->C2H4      DH1 C2H2 +2H2 -> C2H6    DH2 Which expression represents the enthalpy change for the reaction below? C2H4 + H2 -> C2H6                 DH=?
    • A. 

      DH1+ DH2

    • B. 

      DH1 - DH2

    • C. 

      DH2 - DH1

    • D. 

      -DH1- DH2

  • 14. 
    The bond enthalpies of H2, Br2 and HBr are 436, 192, and 366 kJ mol-1 respectively. Use these values to calculate ∆H in kJ for the reaction; H2 (g) + Br2 (g) -> 2HBr(g)
    • A. 

      +262

    • B. 

      –104

    • C. 

      –208

    • D. 

      –262

  • 15. 
    N2 (g) + O2 (g) à 2NO(g)      DH =180.4 kJ             N2 (g) + 202 (g) -> 2NO2 (g)   DH = 66.4 kJ   Use the enthalpy values above to calculate DH for the reaction:       NO(g) + ½ O2 (g) -> NO2 (g)  
    • A. 

      -57 kJ

    • B. 

      -114 kJ

    • C. 

      57 kJ

    • D. 

      114 kJ

  • 16. 
    Which statement about this reaction is correct? 2Fe(s) + 3CO2 (g) -> Fe2O3(s) + 3CO(g)       DH = +26.6 kJ  
    • A. 

      26.6 kJ of energy are released for every mole of Fe reacted

    • B. 

      26.6 kJ of energy are absorbed for every mole of Fe reacted

    • C. 

      53.2 kJ of energy are released for every mole of Fe reacted

    • D. 

      13.3 kJ of energy are absorbed for every mole of Fe reacted

  • 17. 
    Which statement about exothermic reactions is not correct?
    • A. 

      They release energy

    • B. 

      The products have a greater enthalpy than the reactants

    • C. 

      The enthalpy change (∆H) is negative

    • D. 

      The products are more stable than the reactants

  • 18. 
    In an experiment to measure the heat change when a small amount of sodium hydroxide is dissolved in water, x g of sodium hydroxide was dissolved in y g of water, giving a temperature rise of z  OC. The specific heat capacity of water is  c Jg−1 K-1. Which expression should be used to calculate the heat change (in J )?
    • A. 

      Cxyz

    • B. 

      Cyz

    • C. 

      Cxz

    • D. 

      Cxy

  • 19. 
    Some average bond enthalpies (in kJ mol−1) are as follows:  H–H =436 ,     Cl–Cl =242 ,   H–Cl =431 What is the enthalpy change (in kJ) for the decomposition of hydrogen chloride? 2HCl →H2 +Cl2
    • A. 

      −184

    • B. 

      +184

    • C. 

      +247

    • D. 

      −247

  • 20. 
    When solid ammonium nitrate dissolves in water, the temperature decreases.  Which statement about the dissolving of ammonium nitrate in water is correct?
    • A. 

      It is endothermic with ∆H greater than zero.

    • B. 

      It is endothermic with ∆H less than zero.

    • C. 

      It is exothermic with ∆H less than zero.

    • D. 

      It is exothermic with ∆H greater than zero.

  • 21. 
    When 0.01 mol of solid NaOH is added to 100 cm3 of 1.0 mol dm−3  HCl, the temperature increases by ∆T1. What will be the temperature change, ∆T2, for a second experiment in which the amount of NaOH and the volume of 1.0 mol dm−3 HCl are each doubled?
    • A. 

      ∆T2=∆T1

    • B. 

      ∆T2=1/2 ∆T1

    • C. 

      ∆T2=2∆T1

    • D. 

      ∆T2=4∆T1

  • 22. 
    O2(g) →2O(g)                         ∆H= 498 kJ            3O2 (g) →2O 3 (g)                   ∆H= 284 kJ Using the information above, what is ∆H for the following equation in kJ?
    • A. 

      605

    • B. 

      463

    • C. 

      356

    • D. 

      214

  • 23. 
    Which statement about endothermic reactions is not correct?
    • A. 

      They have positive ∆H values.

    • B. 

      Products have a higher enthalpy than the reactants.

    • C. 

      They release energy.

    • D. 

      Products are less thermally stable than the reactants.

  • 24. 
    The enthalpy changes for two reactions involving hydrogen are as follows:          C(s) +2H2 (g) →CH4(g)             ∆H = − 75 kJ H2(g) →2H(g)                         ∆H = + 436 kJ What is the enthalpy change (in kJ) for the reaction CH4 (g) →C(s) +4H(g) A. −947           B. +361           C. +511           D. +947
    • A. 

      +947

    • B. 

      +511

    • C. 

      +361

    • D. 

      −947

  • 25. 
    Which reaction has an enthalpy change equal to four times the bond enthalpy of the C−H bond?
    • A. 

      CH4 (g) → C(s) + 2H2 (g)

    • B. 

      CH4 (g) → C(s) + 4H(g)

    • C. 

      CH4(g) → C(g) + 4H(g)

    • D. 

      CH4 (g) → C(g) + 2H2 (g)

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