The molar heat capacities at constant pressure (assuming constant with respect to temperature) of A, B, and C are in the ratio of 1.5 : 3.0 : 2.0 . If the enthalpy change for the exothermic reaction A

Question

The molar heat capacities at constant pressure (assuming constant with respect to temperature) of A, B, and C are in the ratio of 1.5 : 3.0 : 2.0 . If the enthalpy change for the exothermic reaction A + 2 B ⟶ 3 C at 300 K is − 10 k J / m o l and C p , m ​ ( B ) is 300 J / m o l , then the enthalpy change at 310 K is:

TestHub · Accepted Answer

Reaction: A + 2 B → 3 C Δ H 300 ​ = –10 kJ/mol C p ​ ( A ) : C p ​ ( B ) : C p ​ ( C ) = 1.5 : 3 : 2 C p ​ ( B ) = 300 J / m o l . K → C p ​ ( A ) = 150 J / m o l . K , C p ​ ( C ) = 200 J / m o l . K Δ T = 310 − 300 = 10 K Δ H T ​ = Δ H T 0 ​ ​ + Δ C p ​ × Δ T Δ C p ​ = Σ C p ​ ( p ro d u c t s ) − Σ C p ​ ( re a c t an t s ) Δ C p ​ = 3 × 200 − ( 150 + 2 × 300 ) = 600 − 750 = − 150 J / m o l . K Δ H 310 ​ = − 10 + ( − 150 × 10/1000 ) = − 10 − 1.5 = − 11.5 k J / m o l

Chemistry - Thermochemistry Question with Solution | TestHub

Options:

Doubts & Discussion

JEE Main 2027 (Class 12+)