Barium carbonate is a barely soluble salt that decomposes in the following way.

Question

Barium carbonate is a barely soluble salt that decomposes in the following way. BaCO3(s)BaO(s)+CO2(g) (i) Calculate fG0 for BaCO3 at 25°C given that rG0 = +219.7 kJ mol-1 , fG0 (BaO(s)) = -520.38 kJ mol-1 , and fG0 (CO2(g)) = -394.36 kJ mol-1

(ii) A sample of BaCO3 is placed in a sealed container and allowed to come to equilibrium. Write an expression for the equilibrium constant. In what direction (towards BaCO3 or BaO and CO2) would the equilibrium move if the following happens • the temperature is increased • more CO2 is added, and • more BaCO3 is added? (iii) The solubility product constant for BaCO3 is KSP=2.6×10-9 . If solid BaCO3 is placed in water what will the concentration of Ba2+ ions be? Would the concentration of Ba2+ ions increase if Na2CO3 is added to the solution?

Explanation / Answer

ii) A sample of BaCO3 is placed in a sealed container and allowed to come to equilibrium. Write an expression for

the equilibrium constant.K is [PRODUCTS]/ [REACTANTS]

K of BaCO3 =[BaO] [CO2] / [BACO3]

When the temperature is increased,  the equilibrium moves towards BaO and CO2

When more CO2 is added, the equilibrium moves towards BaO and CO2

When more BaCO3 is added,  the equilibrium moves towards BaCO3

iii) The solubility product constant for BaCO3 is KSP=2.6×10-9

If solid BaCO3 is placed in water, the concentration of Ba2+ ions will be equal to that of the concenraion based on the equilibrium constant of BaCO3.

Solids are not included when calculating equilibrium constant expressions, because their concentrations do not change the expression; any change in their concentrations are insignificant

the concentration of Ba2+ ions will not increase if Na2CO3 is added to the solution.

i) delta fG0(BaCO3) = (delta fG0 (BaO) + delta fG0 (CO2) ) - ( delta rG0 (BaCO3 )

  then, fG0 for BaCO3 = -520.38 - 394.36 - 219.7

= -1134.44 kJ mol-1

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.