Home
Class 11
CHEMISTRY
18.0 g of water completely vaporises at ...

18.0 g of water completely vaporises at `100^(@)C` and 1 bar pressure and the enthalpy change in the process is `40.79 kJ mol^(-1)`. What will be the enthalpy change for vaporising two moles of water under the same conditions ? What is the standard enthalpy of vaporisation for water ?

Text Solution

Verified by Experts

`18.0` g of water `=` 1 mole
`:. ` Standard enthalpy of vaporisation at`100^(@)C` and 1 bar pressure `=40.79 kJ mol^(-1)`
Enthalpy change in vaporisationof 2 moles of water `= 2 xx 40.79 kJ = 81. 58 kJ`
Promotional Banner

Topper's Solved these Questions

  • THERMODYNAMICS

    PRADEEP|Exercise MATCHING TYPE QUESTIONS|8 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise ASSERTION AND REACTION TYPES QUESTIONS|3 Videos

  • THERMODYNAMICS

    PRADEEP|Exercise NCERT EXEMPLAR PROBLEMS WITH ANSWERS, HINTS AND SOLUTIONS( MULTIPLE CHOICE QUESTIONS-II)|5 Videos

  • STRUCTURE OF ATOM

    PRADEEP|Exercise Competition Focus (JEE (Main and Advanced)/Medical Entrance (IX. Assertion And Reason Type Questions (Type II))|12 Videos

Similar Questions

Explore conceptually related problems

Standard enthalpy of formation of water is -286 kJ mol^-1 . Calculate the enthalpy change for formation of 0.018 kg of water.

The standard enthalpy change for the transition of liquid water of steam is 40.8 kJ mol^(-1) at 373 K. Calculate the entropy of vaporisation of water.

One mole of acetone requires less heat to vaporise than 1 mole of water. Which of the two liquids has higher enthalpy of vaporisation ?

If the enthalpy change for the transition of liquid water to steam is 300kJ mol^(-1)" at "27^(@)C , the entropy change for the proces would be

Ethanol boils at 78.4^@C and the enthalpy of vaporisation of ethanol is 42.4kJ mol^(-1) . Calculate the entropy of vaporisation of ethanol.

Knowledge Check

  • The internal energy change for the vapourisation of one mole water at 1 atm and 100°C will be (Enthalpy of vapourization of water is 40.66 kJ

    A
    Zero
    B
    37.56 kJ
    C
    -37.56 kJ
    D
    40.6 kJ

  • If the enthalpy change for the transition of liquid water to steam is 300kJ mol^(-1)" at "27^(@)C , the entropy change for the proces would be

    A
    `1000 JK^(-1)mol^(-1)`
    B
    `10 JK^(-1)mol^(-1)`
    C
    `1.0 JK^(-1)mol^(-1)`
    D
    `0.1JK^(-1)mol^(-1)`

  • If the enthalpy change for the transition of liquid water to steam is 30 kJ mol^(-1) at 27^(@)C , the entropy change for the process would be

    A
    `100 J mol^(-1)K^(-1)`
    B
    `10J mol^(-1) K^(-1)`
    C
    `1.0 J mol^(-1) K^(-1)`
    D
    `0.1 J mol^(-1) K^(-1)`
    • PRADEEP-THERMODYNAMICS-NCERT EXEMPLAR PROBLEMS WITH ANSWERS, HINTS AND SOLUTIONS( SHORT ANSWER QUESTIONS)
    1. 18.0 g of water completely vaporises at 100^(@)C and 1 bar pressure an...

      Text Solution

      |

    2. One mole of acetone requires less heat to vaporise than 1 mole of wate...

      Text Solution

      |

    3. Standard molar enthalpy of formation, Delta(f) H^(Θ) is just a special...

      Text Solution

      |

    4. The value of Delta(f) H^(Θ) for NH(3) is -91.8 kJ mol^(-1). Calculate ...

      Text Solution

      |

    5. Enthalpy is an extensive property. In general, if enthalpy of an overa...

      Text Solution

      |

    6. The enthaply of atomisation for the reaction : CH(4)(g) to C(g) + 4 H(...

      Text Solution

      |

    7. Use the following data to calculate Delta("lattice")H^(@) for NaBr. De...

      Text Solution

      |

    8. Given that DeltaH=0 for mixing of two gases. Explain whether the diffu...

      Text Solution

      |

    9. Heat has randomising influence on a system and temperature is the meas...

      Text Solution

      |

    10. Increase in enthalpy of the surroundings is equal to decrease in entha...

      Text Solution

      |

    11. At 298 K, K(p) for the reaction : N(2)O(4)(g) iff 2NO(2)(g) is 0.98. P...

      Text Solution

      |

    12. A sample of 1.0 mole of a monoatomic ideal gas is taken through a cycl...

      Text Solution

      |

    13. The standard molar entropy of H(2)O(l) is 70 J K^(-1) "mol"^(-1).Wil...

      Text Solution

      |

    14. Identify the state functions and path functions out of the following: ...

      Text Solution

      |

    15. The molar enthalpy of vapourisation of acetone is less than that of wa...

      Text Solution

      |

    16. Which quantity out of Delta(r)G or Delta(r)G^(@) will be zero at equil...

      Text Solution

      |

    17. Predict the change in internal energy for an isolated system at consta...

      Text Solution

      |

    18. Although heat is a path function but heat absorbed by the system under...

      Text Solution

      |

    19. Expansion of a gas in vaccum is called free expansion.Calculate the wo...

      Text Solution

      |

    20. Heat capacity (C(p)) is an extensive property but specific heat (C) is...

      Text Solution

      |