NEET Chemistry Thermodynamics / रासायनिक उष्मागतिकी Question Bank Self Evaluation Test - Thermodynamics

  • question_answer
    How many molecules of ATP, undergo hydrolysis to raise the temperature of 180 kg of water which was originally at room temperature by\[1{}^\circ C\] ? C{P,m} water = 75.32 J/mol/K, \[\Delta H\left\{ P \right\}\] for ATP hydrolysis = 7 kcal/mol

    A) \[1.5\times {{10}^{25}}\]         

    B) \[2.00\times {{10}^{23}}\]

    C) \[3.4\times {{10}^{25}}\]         

    D) \[4.0\times {{10}^{24}}\]

    Correct Answer: A

    Solution :

    [a] \[{{q}_{p}}=\Delta H={{C}_{p}}dT\] \[\Rightarrow {{q}_{p}}=75.32\frac{J}{K\,mol}\times (299-298)K\] \[\Rightarrow {{q}_{p}}=75.32\frac{J}{K\,mol}\] For \[180\text{ }kg\] of water, no. of moles of water \[=\frac{180\times {{10}^{3}}g}{18g/mol}={{10}^{4}}g\,moles\,\] \[{{q}_{p}}=75.32\frac{J}{mol}\times {{10}^{4}}moles\] \[=753.2\times {{10}^{3}}J=753.2\,kJ\] \[\Delta H\] for\[ATP=7kcal/mol\] \[=7\times 4.184\,kJ/mol\] \[=29.2kJ/mol\] \[6.022\times {{10}^{23}}\] molecules of ATP produce \[=29.2\text{ }kJ\] \[29.2\text{ }kJ\] produced from \[6.022\times {{10}^{23}}\] molecules \[753.2\text{ }kJ\] produced from \[6.022\times {{10}^{23}}\times \frac{75.8}{29.2}\] \[=1.5\times {{10}^{25}}\] molecules


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