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Question: For \(CaC{O_3}(s)\overset {} \leftrightarrows CaO(s) + C{O_2}(g),\,{K_c}\,\)is equal to: A. \(\lef...

For CaCO3(s)⇆CaO(s)+CO2(g), Kc CaC{O_3}(s)\overset {} \leftrightarrows CaO(s) + C{O_2}(g),\,{K_c}\,is equal to:
A. [CO2]\left[ {C{O_2}} \right]
B. [CaO]\left[ {CaO} \right]
C.[CaCO3]\left[ {CaC{O_3}} \right]
D. None of these.

Explanation

Solution

The equilibrium constant is a ratio of the concentration of the products to the concentration of the reactants. If the K value is less than one the reaction will move to the left and if the K value is greater than one the reaction will move to the right.

Complete step by step answer:
Equilibrium constant Kc{K_c}, is the ratio of equilibrium concentrations of products over the equilibrium concentrations of reactants each raised to the power of their stoichiometric coefficients.
For a reaction:aA+bB→cC+dDaA + bB\xrightarrow{{}}cC + dD
Equilibrium constant: Kc{K_c}=[C]c[D]d[A]a[B]b\dfrac{{{{[C]}^c}{{[D]}^d}}}{{{{[A]}^a}{{[B]}^b}}}
Calculation of Kc{K_c}:
For the gas phase reaction- The concentrations of gases are corporated in its value. The concentrations of gases are expressed in the formula of equilibrium constant.
For pure solid and liquids: Concentrations of pure solids and liquids are fixed by their density and molar mass (both constants) and do not vary with the amount.
Thus , the concentration of solids and liquids are incorporated in the value of Kc{K_c}, they are not part of variable expressions.
Solve the given question;
CaCO3(s)→CaO(s)+CO2(g)CaC{O_3}(s)\xrightarrow{{}}CaO(s) + C{O_2}(g)
Write all the values of stoichiometric coefficients ;
a=1, b=0, c=1, d=1;
we know that in the equation part concentration of only gaseous part will be present.
So the equation of Kc{K_c}will be equal to Kc=[CO2]{K_c} = [C{O_2}]
Because the concentration of only gaseous parts will be present in the equation , concentration of solids and liquids would be absent , as we have discussed earlier. Stoichiometric coefficient is 1 . So power is raised to power 1.
So, our final answer would be [CO2]\left[ {C{O_2}} \right] option (A).

Note: Characteristics of Kc{K_c}:
Equilibrium can be approached from both direction
Kc{K_c} is independent of initial concentration of reactants and products and also of temperature.