Increase in enthalpy of the surroundings is equal to decrease in enthalpy of the system. Will the temperature of system and surroundings be the same when they are in thermal equilibrium?
Yes, the temperature of system and surroundings be the same when they are in thermal equilibrium.
At $298 \mathrm{~K}, K_p$ for reaction $\mathrm{N}_2 \mathrm{O}_4(g) \rightleftharpoons 2 \mathrm{NO}_2(g)$ is 0.98 . Predict whether the reaction is spontaneous or not.
For the reaction, $\mathrm{N}_2 \mathrm{O}_4(g) \rightleftharpoons 2 \mathrm{NO}_2(g), K_p=0.98$
As we know that $\quad \Delta_r G^{\mathrm{s}}=-2.303 R \mathrm{log} K_p$
Here, $K_p=0.98$ i.e., $K_p<1$ therefore, $\Delta_r G^{\circ}$ is positive, hence the reaction is non-spontaneous.
A sample of 1.0 mol of a monoatomic ideal gas is taken through a cyclic process of expansion and compression as shown in figure. What will be the value of $\Delta H$ for the cycle as a whole?
The net enthalpy change, $\Delta H$ for a cyclic process is zero as enthalpy change is a state function, i.e., $\Delta H$ (cycle) $=0$
The standard molar entropy of $\mathrm{H}_2 \mathrm{O}(l)$ is $70 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$. Will the standard molar entropy of $\mathrm{H}_2 \mathrm{O}(s)$ be more, or less than $70 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$ ?
The standard molar entropy of $\mathrm{H}_2 \mathrm{O}(l)$ is $70 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$. The solid form of $\mathrm{H}_2 \mathrm{O}$ is ice. In ice, molecules of $\mathrm{H}_2 \mathrm{O}$ are less random than in liquid water.
Thus, molar entropy of $\mathrm{H}_2 \mathrm{O}(\mathrm{s})<$ molar entropy of $\mathrm{H}_2 \mathrm{O}(l)$. The standard molar entropy of $\mathrm{H}_2 \mathrm{O}(\mathrm{s})$ is less than $70 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$.
Identify the state functions and path functions out of the following: enthalpy, entropy, heat, temperature, work, free energy.
State functions are those values which depend only on the state of the system and not on how it is reached e.g., enthalpy, entropy, temperature and free energy. Path functions are those values which depend on the path of the system. e. $g$, heat and work.