Q . FOR THE REACTION :-

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

K_p = 1.16 atm AT 800⁰C .

IF 20.0 g OF CaCO₃ WERE KEPT IN A 10 L CONTAINER AND HEATED UP TO 800⁰ C , WHAT PERCENTAGE OF CaCO₃ WOULD REMAIN UNREACTED AT EQUILIBRIUM.

CaCO3(s)------------------------> CaO (s) + CO2(g)
20g.....................................0g...........0g........(initially)
Kp=P_CO2=1.16atm(as the solids are notincluded in the expression as their active mass is unity.)

Volume=10L, T=800K,So the number of moles of CO2 at equilibrium= can be calculated using ideal gas equation.
PV=nRT
n= {(1.16*10)/(0.082*800)} mol
and this much mole of CaCO3 would be consumeed .
So mass ofCaCO3=100g/mol *n
So mass left=20g-n*100g=l(let)
so % of CaCO3 unreacted=(l/20)*100