Quiz  /  Heat of Reaction Class 12 MCQ Questions With Answers

  • 1. 
    Check only the FALCE statements:

  • The heat change at the end of a chemical reaction under constant pressure is called the bond energy.
  • Melting of salt is an exothermic process.
  • Freezing is an endothermic process.
  • All of above

  • 2. 
    Check only the TRUE statements:

  • In endothermic reaction, the total energy of products is bigger than that of reactants.
  • Melting is an endothermic process.
  • Sublimation is the physical process when solid turns to gas.
  • All of above

  • 3. 
    Which one of the following reactions are endothermic?

  • Fe(s)→Fe(l)
  • 2C+2H2+20kcal/mol → C2H
  • Ba(OH)2+CO2 → BaCO3+H2O+heat
  • Both A & B

  • 4. 
    In a chemical reaction, energy is used to :

  • cause a change of state
  • overcome intermolecular forces
  • break or form bonds within molecules
  • All of above

  • 5. 
    At which point is the substance a solid?

  • A
  • C
  • E
  • B

  • 6. 
    What is the latent heat of fusion?

  • 4.6 kJ
  • 838.4 kJ
  • 10.15 kJ
  • 3.0 kJ

  • 7. 
    Exothermic reactions feel

  • warm
  • cold

  • 8. 
    Consider the reaction: 2 H2O + energy → 2H2 + O2

  • exothermic, releasing energy
  • exothemic, absorbing energy
  • endothermic, absorbing energy
  • endothermic, releasing energy

  • 9. 
    Endothermic reactions feel

  • warm
  • cold

  • 10. 
    How much heat is required to vaporize 150. g of water at 100∘C?

  • 62.7 kJ
  • 50.1 kJ
  • 150. kJ
  • 339 kJ

  • 11. 
    During a phase change, the temperature...

  • Increases
  • Decreases
  • Does nothing
  • Fluctuates

  • 12. 
    The amount of heat required to raise the temperature of one gram of a substance by one degree Celsius is ________

  • Heat energy
  • Specific heat
  • convection
  • thermal energy

  • 13. 
    Heat is measured in

  • joules
  • grams
  • degrees celcius
  • mililiters

  • 14. 
    The reaction between 25.0 cm3 of hydrochloric acid and 25.0 cm3 of sodium hydroxide solution releases the heat of 2100 J.What is the temperature change of the mixture?[Specific heat capacity of a solution = 4-2 Jg ^C"1;Assume that 1 cm3 of a solution is equal to 1 g of the solution]

  • 1°C
  • 2°C
  • 10 °C
  • 20 °C

  • 15. 
    What letter represents boiling?

  • B
  • C
  • D
  • E

  • 16. 
    Diagram 14 shows an energy level diagram for propan-1-ol. Which of the following sattement is correct about the reaction?

  • X kJ of heat is absorbed during the reaction.
  • The final temperature is lower than initial temperature.
  • The heat of combustion of propan-1-ol is -X kJ/mol
  • The total energy content of product is higher than the reactant.

  • 17. 
    Which of the following is an endothermic reaction?

  • HCI + NaOH → NaCl + H2O
  • HCI + NaHCO3 → NaCl + CO2 + H2O
  • NaCl + AgNO3 → AgCl + NaNO3
  • Zn + CuSO4 → ZnSO4 + Cu

  • 18. 
    What is latent heat?

  • heat that cause a temperature increase
  • heat that causes a temperature decrease
  • heat used/released in a phase change
  • large heat

  • 19. 
    In an experiment, 100 cm3 of dilute hydrochloric acid solution is mixed with 100 cm3 sodium hydroxide solution in a polystyrene cup. The concentrations of the two solutions are the same. During the mixing, the temperature of the mixture increased by 7 0C.What is the heat released in the experiment?Given that the specific heat capacity of the solution is 4.2 J g-1 0C-1.

  • 1470 J
  • 2940 J
  • 4410 J
  • 5880 J

  • 20. 
    How much heat is required to melt 26.0 g of ice at 0∘C?

  • 5.88 x 104 kJ
  • 8.68 kJ
  • 109 J
  • 0 kJ

  • 21. 
    Calorimetry Question:A piece of metal with a mass of 82.9 g is heated to 100.5°C and dropped into 71.4 g of water at 20.0°C. The final temperature of the system is 30.2°C. What is the identity of the metal?

  • Iron
  • Copper
  • Gold
  • Titanium

  • 22. 
    The following information shows the results of an experiment to determine the heat change for the combustion of propanol, C3H7OH.Volume of water in the copper container= 300 cm3Initial temperature of water in copper container=27.5 °CHighest temperature of water in copper container = 68.5 °CWhat is the heat released by the combustion of propanol, C3H7OH? [Specific heat capacity of water = 4.2 J g-1°C-1 ; Water density = 1 g cm-3]

  • 34.65 kJ
  • 51.66 kJ
  • 86.3 kJ
  • 120.96 kJ

  • 23. 
    Why does the graph have two flat lines at "b" and "d"?

  • Those are times when we took the water off the hot plate
  • Those are phase changes where temperature doesn't change while adding heat
  • The line is flat because the water is all in the solid or gas phase
  • The line is flat because temperature increases the most at those locations

  • 24. 
    The table shows the heat of combustion of three alcohols.Which of the following factors increases the heat of combustion of alcohols?

  • Size of molecules decreases
  • Number of carbon atoms per molecule increases
  • Number of oxygen atoms per molecule increases
  • Number of hydrogen atoms per molecule decreases

  • 25. 
    The following is the energy level diagram of a reaction. Which of the following acids is suitable to replace nitric acid, HNO3 to obtain the same ΔH value ?

  • Ethanoic acid, CH3COOH
  • Carbonic acid, H2CO3
  • Sulphuric acid, H2SO4
  • Hydrochloric acid, HCl
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