COMEDK2014ChemistryThermodynamics (C)
Standard molar enthalpies of formation of CaCO ₃(s), CaO (s) and CO ₂(g) are -1206.92 ~kJ ~mol ⁻¹,-635.09 ~kJ ~mol ⁻¹ and -393.51 ~kJ ~mol ⁻¹ respectively. The _ r H , for decomposition of CaCO ₃(s) is
Options
- A178.3 ~kJ ~mol ⁻¹
- B-178.3 ~kJ ~mol ⁻¹
- C1448.5 ~kJ ~mol ⁻¹
- D-1448.5 ~kJ ~mol ⁻¹
Correct answer
A. 178.3 ~kJ ~mol ⁻¹
Step-by-step solution
CaCO ₃(s) CaO (s)+ CO ₂(g) aligned _ r H^ &= _ f H^ ( CaO )+ _ f H^ ( CO ₂ )- _ f H^ ( CaCO ₃ ) &=-635.09+(-393.51)-(-1206.92) &=178.3 ~kJ ~mol ⁻¹ . aligned