Just need help finding the temperature, please. Enormous amounts of lime (CaO) a

Question

Just need help finding the temperature, please.

Enormous amounts of lime (CaO) are used in steel industry blast furnaces to remove impurities from iron. Lime is made by heating limestone and other solid forms of CaCo_3(s). Why is the standard molar entropy of CaCO_3(s) higher than that of CaO(s)? S^0 for CaCO_3 is greater than S^0 for CaO because there are more atoms in CaCO_3. S^0 for CaCO_3 is greater than S^0 for CaO because CaO is more stable. S^0 for CaCO_3 is greater than S^0 for CaO because CaCO_3 is more stable. At what temperature is the pressure of CO_2(g) over CaCO_3(s) equal to 1.0 atm?

Explanation / Answer

The reaction is,

CaO (s) + CO2 (g) -----> CaCO3 (s)

Kp for the reaction = 1 / Partial Pressure of CO2

Given,

Partial Pressure of CO2 required = 1 atm

=> Kp = 1 / 1 = 1

We know that,

delta G = - RT ln Kp = - RT ln (1) = 0 (since ln (1) = 0)

Also,

delta G = delta H - (T * delta S)

delta Hrxn. = (-1207) - (-636 -394) = - 177 kJ = -177000 J

delta Srxn. = (93) - (40 + 214) = -161 J / mol K

delta G = 0

=> 0 = -177000 - (T * -161)

=> T = 177000 / 161 = 1099.4 K = 826.23 degree C

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