Final answer:
The standard change in entropy for the melting of iodobenzene at its melting point is 0.040 J/(mol·K). The standard free energy change for the reaction N₂O4 (g) = 2NO₂ (g) at 1000 K is -10,819.4 J/mol. The change in internal energy of the gas that absorbs 0.0 J of heat and performs 99.5 J of work is -99.5 J.
Step-by-step explanation:
The standard enthalpy of fusion of iodobenzene is 9.75 kJ/mol at its melting point, 241.8 K. The standard change in entropy for the melting of iodobenzene at its melting point can be calculated using the equation: ΔS = ΔH_fus / T, where ΔS is the standard change in entropy, ΔH_fus is the standard enthalpy of fusion, and T is the temperature in Kelvin. Plugging in the values, we get: ΔS = 9.75 kJ/mol / 241.8 K = 0.040 J/(mol·K).
The equilibrium constant for the reaction N₂O4 (g) = 2NO₂ (g) at 1000 K is given as Kp = 0.142. The standard free energy change can be calculated using the equation: ΔG = -RT ln(K), where ΔG is the standard free energy change, R is the gas constant (8.31 J/(K·mol)), T is the temperature in Kelvin, and ln(K) is the natural logarithm of the equilibrium constant. Plugging in the values, we get: ΔG = -8.31 J/(K·mol) * 1000 K * ln(0.142) = -10,819.4 J/mol.
For the gas that absorbs 0.0 J of heat and performs 99.5 J of work, the change in internal energy can be calculated using the first law of thermodynamics: ΔU = Q - W, where ΔU is the change in internal energy, Q is the heat absorbed, and W is the work done. Plugging in the values, we get: ΔU = 0.0 J - 99.5 J = -99.5 J.