Home
Class 12
CHEMISTRY
Since the enthalpy of elements in their ...

Since the enthalpy of elements in their natural state is taken to be zero, the heat of formation `(Delta_(f)H)` of compounds

A

is always negative

B

is always positive

C

may be negative or positive

D

is zero

Text Solution

Verified by Experts

The correct Answer is:
C
`Delta H_(f)` may be + ve or -ve depends on the stability of the product formed.
Promotional Banner

Topper's Solved these Questions

  • CHEMICAL THERMODYNAMICS AND ENERGETICS

    MARVEL PUBLICATION|Exercise MULTIPLE CHOICE QUESTIONS (Third Law of Thermodynamics)|6 Videos

  • CHEMICAL THERMODYNAMICS AND ENERGETICS

    MARVEL PUBLICATION|Exercise MULTIPLE CHOICE QUESTIONS (HIGHER LEVEL)|112 Videos

  • CHEMICAL THERMODYNAMICS AND ENERGETICS

    MARVEL PUBLICATION|Exercise MULTIPLE CHOICE QUESTIONS (Spontaneous Process, Entropy and Second Law of Thermodynamics)|16 Videos

  • CHEMICAL KINETICS

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP|50 Videos

  • CHEMISTRIY IN EVERYDAY LIFE

    MARVEL PUBLICATION|Exercise TEST YOUR GRAPS|24 Videos

Similar Questions

Explore conceptually related problems

The enthalpies of all elements in their standard states are :

MARVEL PUBLICATION-CHEMICAL THERMODYNAMICS AND ENERGETICS-MULTIPLE CHOICE QUESTIONS (Gibbs Free Energy)
  1. Which of the following is true fo the reacion H(2)O(l)hArr H(2)O(g) at...

    Text Solution

    |

  2. For a system in equilibrium, DeltaG=0, under conditions of constant

    Text Solution

    |

  3. Since the enthalpy of elements in their natural state is taken to be z...

    Text Solution

    |

  4. At constant T and P which of the following statement is correct for th...

    Text Solution

    |

  5. A chemical reaction will be spontaneous if it is accompanied by a decr...

    Text Solution

    |

  6. The standard Gibb's free energy change, DeltaG^(@) is related to equil...

    Text Solution

    |

  7. Mark the correct statement.

    Text Solution

    |

  8. One mole ofan ideal gas is allowed to expand freely and adiabatically ...

    Text Solution

    |

  9. According to the second law of thermodynamics, a process (reaction) is...

    Text Solution

    |

  10. Mechanical work is specially important in systems that contain

    Text Solution

    |

  11. The favourable conditions for a spontaneous reaction are

    Text Solution

    |

  12. Free enegry , G = H - TS, is state function that indicates whther a re...

    Text Solution

    |

  13. The enthalpy of vaporization of a substance is 840 J per mol and its b...

    Text Solution

    |

  14. If the enthalpy of vaporisation of water is 186.5 J mol^(-1), then ent...

    Text Solution

    |

  15. If 900J//g of heat is exchanged at boiling point of water then water...

    Text Solution

    |

  16. Two moles of ideal gas at 27^(@)C temperature is expanded reversibly f...

    Text Solution

    |

  17. What is the free energy change, 'DeltaG' When 1.0 mole of water at 100...

    Text Solution

    |

  18. Calculate the temperature at which DeltaG=-5.2 kJmol^-1,DeltaH=145.6kJ...

    Text Solution

    |

  19. Calculate the free energy change for the following reaction at 300 K. ...

    Text Solution

    |

  20. One mole of a perfect gas expands isothermally to ten times its origin...

    Text Solution

    |