Marks: 1 For the reaction: CaCO3(s) ? CaO(s) + CO2(g) Kp= 1.16 atm at 800oC The
ID: 597512 • Letter: M
Question
Marks: 1
For the reaction:
CaCO3(s) ? CaO(s) + CO2(g) Kp= 1.16 atm at 800oC
The system is at equilibrium. There are 2 mol of CaCO3, 6 mol CaO, and the CO2 pressure is 1.16 atm at 800oC. Which of the following produces more CO2 at the new equilibrium?
Equilibrium Expression and Solids
Choose at least one answer.
a. mol CaCO3 decreases.
b. mol CaCO3 increases.
c. mol CaO decreases.
d. mol CaO increases.
e. The volume of the container increases (pressure drops).
f. The volume of the container decreases (pressure increases).
Explanation / Answer
2HBr(g) ? H2(g) + Br2(g) 2 mole ------1 mole 1 mole 2 volume ---- 1 volume 1 volume 2 volume ---- 2 volume There is no effect of increasing or decreasing pressure on this equilibrium because there is no change in volume. So, there is no change in amount of reactants and product. So, the correct answers are: a. In the balances equation there are 2 moles of reactant gas to 2 moles of product gas. c. mol H2 stays the same. f. mol HBr remains the same. i. mol Br2 stays the same. # CaCO3(s) ? CaO(s) + CO2(g) Kp= 1.16 atm at 800oC 1 mole ---------1 mole --- 1 mole 0volume ------ 0volume 1 volume 0 volume ------------------1 volume So, forward reaction is volume increasing reaction and reverse reaction is volume decreasing reaction. According to Lechatelier's principle, to produce more CO2 (g), forward reaction must be favoured. i.e. volume increasing reaction is favoured (It means pressure to be decreased) Concentration effect: If more amount of CaCO3 is added into equilibrium, the equilirbium will shift to left producing more CO2. (i.e. increase mole of CaCO3) If CaO and CO2 is decreased, the forward reaction is occurred to produce more CO2 and CaO to maintain the equilibrium, So, decrease CaO and CO2. The correct answer are: b. mol CaCO3 increases. c. mol CaO decreases. e. The volume of the container increases (pressure drops).