1. Tardigrade
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  3. Chemistry
  4. Consider the following reaction occurring in an automobile 2 C 8 H 18( g )+25 O 2( g ) longrightarrow 16 CO 2( g )+18 H 2 O ( g ) the sign of Δ H, Δ S and Δ G would be

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Q. Consider the following reaction occurring in an automobile $2 C _8 H _{18}( g )+25 O _2( g ) \longrightarrow 16 CO _2( g )+18 H _2 O ( g )$ the sign of $\Delta H, \Delta S$ and $\Delta G$ would be

AIPMTAIPMT 1994Thermodynamics

Solution:

This is combustion reaction, which is always exothermic hence
$\Delta H = - ve$
As the no. of gaseous molecules are increasing hence entropy increases now $\Delta G = \Delta H - T \Delta S$
For a spontaneous reaction $\Delta G = - ve $
Which is possible in this case as $\Delta H = -ve$ and $\Delta S = + ve$