MCQs on Heat of Reaction

The heat of reaction is the quantity of heat released or absorbed when the number of moles of reactants indicated by the chemical equation has completely reacted. The amount of heat energy given out or taken in during a chemical reaction is called the enthalpy change or the heat of reaction. The symbol for this is 𐤃H. The heat of reaction is usually measured in kilojoules. The heat of reaction is either negative or positive. For exothermic reactions, 𐤃H is negative. For endothermic reactions, 𐤃H is positive. The heat of a reaction was determined, either directly or calculated indirectly from the heat of combustion data, because it was thought at the time that the heat change, 𐤃H, was the sole driving force of a chemical reaction.

1. The energy released in the form of nuclear radiation in addition to heat and light during nuclear reactions is known as

  1. chemical energy
  2. nuclear energy
  3. heat energy
  4. electrical energy

Answer: (b)

2. Fireworks release energy in the form of

  1. heat
  2. sound
  3. light
  4. all of the above

Answer: (d)

3. The energy obtained from electric cells and batteries as a result of a chemical reaction is called

  1. chemical energy
  2. nuclear energy
  3. heat energy
  4. electrical energy

Answer: (a)

4. As the rain falls the potential energy changes to

  1. thermal energy
  2. chemical energy
  3. kinetic energy
  4. nuclear energy

Answer: (c)

5. The energy coming directly from magma called

  1. mechanical energy
  2. geothermal energy
  3. heat energy
  4. electrical energy

Answer: (b)

6. In the process of rubbing hands, mechanical energy is converted into

  1. sound energy
  2. electrical energy
  3. thermal energy
  4. heat energy

Answer: (c)

7. When a body vibrates, it produces

  1. sound
  2. water
  3. heat
  4. electricity

Answer: (a)

8. In the exothermic reaction, the enthalpy of reaction is always

  1. zero
  2. positive
  3. negative
  4. none of these

Answer: (c)

9. The heat required to raise the temperature of 1 mole of a substance by 1o is called

  1. specific heat
  2. molar heat capacity
  3. water equivalent
  4. specific gravity

Answer: (b)

10. The amount of heat required to raise the temperature of a body through 1oC is called its

  1. molar heat
  2. specific heat
  3. entropy
  4. thermal capacity

Answer: (b)

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