Question

CaCO3(s) = Cao (s)+CO2 (g) When heated strongly, solid calcium carbonate decomposes to produce solid calcium oxide and carbon dioxide gas, as represented by the equation above. A 2.0 mol sample of CaCO3(s) is placed in a rigid 100. L reaction vessel from which all the air has been evacuated. The vessel is heated to 898°C at which time the pressure of CO2(g) in the vessel is constant at 1.00 atm, while some CaCO3(s) remains in the vessel. a. Calculate the number of moles of CO2(g) present in the vessel at equilibrium. b. Write the expression for Kp, the equilibrium constant for the reaction, and determine its value at 898°C. c. The experiment was repeated, but this time starting with a 4.0 mol sample of CaCO3(s). On the following graph, draw a curve showing how the pressure of CO2(g) would change over time as the vessel is heated to 898°C and equilibrium is established. 2.001 Pressure of CO2 (atm) 0.00+ Time

Answer 1

equilibrium Moles of Coloz used: 2.0 mol Volume of vessel = 100.0L The time at which pressure in the vessel remain constant is condition, hence Em pressure of co= 1.00 atm Temperature: 898°C = 898+Q43 = 11716 R=0.082 L atolmol.k. PV: MRT n PV RT nr 1.00x100 0.082 x 1171 = 1.04 mol of ca is not taken) kp: PCos & 2.000 (pressure of solid K= [co.] [cao [caco) As concentration of solid is taken as 1. k. [co, k moet hou. 0.0104 en Amu Hence Hence o for a given temp., equilibrium constant remains contant and hence pressure of co will be remain on the same i.e. Iatm 2.007 100 pressure time