Home › JEE Main › Thermodynamics & Kinetic Theory › A reaction is found to have $\Delta H = +30\,\te…
A reaction is found to have $\Delta H = +30\,\text{kJ mol}^{-1}$ and $\Delta S = +100\,\text{J K}^{-1}\,\text{mol}^{-1}$ at $1\,\text{atm}$. The reaction is spontaneous when:
AAt all temperatures
BAt no temperature
C$T > 300\,\text{K}$
D$T < 300\,\text{K}$
Answer & Solution
Correct answer: C. $T > 300\,\text{K}$
$\Delta G = \Delta H - T\Delta S$. For spontaneity $\Delta G < 0$, so $T > \Delta H/\Delta S = 30{,}000 / 100 = 300\,\text{K}$. Both $\Delta H$ and $\Delta S$ are positive, so spontaneity is favoured by higher temperature.
Related questions
A reaction has $\Delta H = -100$ kJ and $\Delta S = +200$ J/K. At $T = 298$ K, $\Delta G$ Among solid ice, liquid water, and water vapour at the same temperature, entropy is:Hess's law states that the standard enthalpy change for a reaction:For a reaction occurring at constant pressure in an open beaker, the heat absorbed equals:There are two spherical balls $A$ and $B$ of the same material with same surface, but the A cylindrical rod with one end in a steam chamber and the other end in ice results in meltAn ideal gas expands isothermally from a volume $V_{1}$ to $V_{2}$ and then compressed to Two cylinders $A$ and $B$ fitted with pistons contain equal amounts of an ideal diatomic g