For a reaction, CaCO3(s) → CaO(s)+CO2(g) ΔfH° (CaO) = - 635.1 kj mol-1, Δ fH° (CO2)=-393.5 kj mol-1 and Δ fH° (CaCO3)= -1206.9 kj mol-1 Which of the following is a correct statement?

Question

For a reaction, CaCO3(s) → CaO(s)+CO2(g) ΔfH° (CaO) = - 635.1 kj mol-1, Δ fH° (CO2)=-393.5 kj mol-1 and Δ fH° (CaCO3)= -1206.9 kj mol-1 Which of the following is a correct statement? (A) A large amount of heat is evolved during the decomposition of CaCO3. (B) Decomposition of CaCO3 is an endothermic process and heat is provided for decomposition (C) The amount of heat evolved cannot be calculated from the data provided (D) ΔrH° = Sigma ΔfH° (reactants) - Sigma Δ fH° (products)

Tardigrade Admin · Accepted Answer

ΔrH = SigmafH°P - Sigma Δ fH° R = [- 635.1 + (-393.5)] - [-1206.9] = + 178.4 kj

Q. For a reaction,
$C a C O_{3 (s)} \to C a O_{(s)} + C O_{2 (g)}$
$Δ_{f} H^{\circ} (C a O) = - 635.1 kj m o l^{- 1}$ ,
$Δ_{f} H^{\circ} (C O_{2}) = - 393.5 kj m o l^{- 1}$ and
$Δ_{f} H^{\circ} (C a C O_{3}) = - 1206.9 kj m o l^{- 1}$
Which of the following is a correct statement?

$A$ large amount of heat is evolved during the decomposition of $C a C O_{3}$ .

Decomposition of $C a C O_{3}$ is an endothermic process and heat is provided for decomposition

The amount of heat evolved cannot be calculated from the data provided

$Δ_{r} H^{\circ} = Σ Δ_{f} H^{\circ}$ (reactants) $- Σ Δ_{f} H^{\circ}$ (products)

$Δ_{r} H = Σ_{f} H_{P}^{\circ} - Σ Δ_{f} H_{R}^{\circ}$
$= [- 635.1 + (- 393.5)] - [- 1206.9] = + 178.4 kj$

Q. For a reaction, CaCO3(s)​→CaO(s)​+CO2(g)​ Δf​H∘(CaO)=−635.1kjmol−1, Δf​H∘(CO2​)=−393.5kjmol−1 and Δf​H∘(CaCO3​)=−1206.9kjmol−1 Which of the following is a correct statement?

A large amount of heat is evolved during the decomposition of CaCO3​.

Decomposition of CaCO3​ is an endothermic process and heat is provided for decomposition