Question

For the reaction below, Kp = 1.16 at 800.°C. CaCO3(s) equilibrium reaction arrow CaO(s) + CO2(g) If a 25.0-g sample of CaCO3 is put into a 14.4 L container and heated to 800°C, what percentage by mass of the CaCO3 will react to reach equilibrium?

Answer 1

Answer:

76.0%

Explanation:

Let's consider the following reaction.

CaCO₃(s) ⇄ CaO(s) + CO₂(g)

At equilibrium, the equilibrium constant Kp is:

Kp = 1.16 = pCO₂ ⇒ pCO₂ = 1.16 atm

We can calculate the moles of CO₂ at equilibrium using the ideal gas equation.

$P.V=n.R.T\\n=\frac{P.V}{R.T} =\frac{1.16atm\times 14.4 L}{(0.08206atm.L/mol.K)\times 1073K} =0.190mol$

From the balanced equation, we know that 1 mole of CO₂ is produced by 1 mole of CaCO₃. Taking into account that the molar mass of CaCO₃ is 100.09 g/mol, the mass of CaCO₃ that reacted is:

$0.190molCO_{2}.\frac{1molCaCO_{3}}{1molCO_{2}} .\frac{100.09gCaCO_{3}}{1molCaCO_{3}} =19.0gCaCO_{3}$

The percentage by mass of the CaCO₃ that reacted to reach equilibrium is:

$\frac{19.0g}{25.0g} \times 100\%=76.0\%$