2. Questions Bank
  3. JEE Main & Advanced
  4. Chemistry
  5. Thermodynamics / रासायनिक उष्मागतिकी

JEE Main & Advanced Chemistry Thermodynamics / रासायनिक उष्मागतिकी Question Bank Heat of reaction

  • question_answer
    Values of heats of formation for \[Si{{O}_{2}}\]and \[MgO\] are \[-48.4\] and \[-34.7\,kJ\] respectively. The heat of the reaction \[2Mg+Si{{O}_{2}}\to 2MgO+Si\] is                [KCET 1990]

    A)                 \[21.16\,kJ\]      

    B)                 \[-21.10\,kJ\]

    C)                 \[-13.62\,kJ\]    

    D)                 \[13.6\,kJ\]

    Correct Answer: B

    Solution :

           \[\Delta {{H}_{(\text{reaction})}}=2\Delta H_{f}^{0}\,(MgO)=-\Delta H_{f}^{0}\,(Si{{O}_{2}})\]                            \[=2\,(-\,34.7)-(-\,48.4)=-21\,kJ.\]


You need to login to perform this action.
You will be redirected in 3 sec spinner