For N2(g) + 3H2(g) -> 2NH3(g), Delta H_298=-92.2 kJ. Assume constant molar heat capacities C_P (in J mol^-1K^-1): N2=29.1, H2=28.8, NH3=35.1, and R=8.314 J mol^-1K^-1. Select the correct statement(s).

Delta C_P=-45.3 J K^-1 for the reaction as written.

|Delta H| decreases as the temperature is raised.

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3td155

For $N X_{2} (g) + 3 H X_{2} (g) 2 NH X_{3} (g)$ , $Δ H_{298} = - 92.2 kJ$ . Assume constant molar heat capacities $C_{P}$ (in $J mo l^{- 1} K^{- 1}$ ): $N X_{2} = 29.1$ , $H X_{2} = 28.8$ , $NH X_{3} = 35.1$ , and $R = 8.314 J mo l^{- 1} K^{- 1}$ . Select the correct statement(s).

Δ C_{P} = 2 (35.1) - 29.1 - 3 (28.8) = - 45.3 J K^{- 1}

(true). Kirchhoff:

Δ H_{400} = - 92.2 + (- 45.3) (102) /1000 = - 96.8 kJ

(true), so

∣Δ H ∣

increases with

T

(statement 3 false). With

Δ n_{g} = - 2

Δ U_{298} = Δ H - Δ n_{g} RT = - 92.2 + 4.96 = - 87.2 kJ

, not

- 97.2

(false).