2. Solved Papers
  3. JEE Main & Advanced

JEE Main & Advanced JEE Main Paper (Held on 10-4-2019 Afternoon)

  • question_answer
    The difference between \[\Delta H\]and \[(\Delta H-\Delta U),\]when the combustion of one mole of heptane (1) is carried out at a temperature T, is equal to: [JEE Main 10-4-2019 Afternoon]

    A) 3RT

    B)               -3RT

    C) -4RT

    D) 4RT

    Correct Answer: C

    Solution :

    \[{{C}_{7}}{{H}_{16}}(\ell )+11{{O}_{2}}(g)\xrightarrow[{}]{{}}7C{{O}_{2}}(g)+8{{H}_{2}}O(\ell )\]           \[\Delta {{n}_{g}}={{n}_{p}}-{{n}_{r}}=7-11=-4\]           \[\because \]\[\Delta H=\Delta U+\Delta {{n}_{g}}RT\]           \[\therefore \]\[\Delta H-\Delta U=-4RT\]            


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