Given that standard molar enthalpies of formation of NO(g) and NO₂(g) are respectively 90.3 kJ/mol and 33.2 kJ/mol, the enthalpy change for the reaction 2NO(g) + O₂(g) → 2NO₂(g) is

Standard entropy of crystalline carbon monoxide (in kJ/mol) at 0 K is around

A. 0.03

B. 2.50

C. zero

D. 5.76

For an irreversible adiabatic expansion of a perfect gas from volume V_i to V_f, the change in entropy of the gas is

A. nR In(V_f/V_i)

B. zero

C. less than zero

D. greater than zero

The change in entropy when two moles of argon gas are heated at constant volume from 300 K to 500 K is

A. -12.74 J/K/mol

B. -6.37 J/K/mol

C. 6.37 J/K/mol

D. 12.74 J/K/mol

For the reaction, N₂(g) + 3H₂(g) → 2NH₃(g)
compute the entropy change (in J/K/mol) for the process and comment on the sign of the property.

A. ΔS° = -37.65 J/K/mol; negative sign indicates that there is a decrease in the gaseous species during the reaction

B. ΔS° = -198.7 J/K/mol; negative sign indicates that there is a decrease in the gaseous species during the reaction

C. ΔS° = -31.25 J/K/mol; negative sign indicates that there is a decrease in the gaseous species during the reaction

D. ΔS° = +31.25 J/K/mol; positive sign indicates that the reaction is spontaneous