Question

The amount of carbon dioxide in a gaseous mixture of CO2 and CO can be determined by passing the gas into an aqueous solution that contains an excess of Ba(OH)2, The CO2 reacts, yielding a precipitate of BaCO3, but eh CO does not react. This method was used to analyze the equilibrium compostion of the gas obtained when 1.77 g of CO2 reacted with 2.0 g of graphite in a 1.000 L container at 1100 K. The analysis yielded 3.41 g of BaCO3. Use these data to calculate Kp at 1100 for the reaction. CO2(g) + C(s) (those two sideways arrow--I don't know how to type them) 2 CO (g). Please answer the blanks or BOLD your answers. Questions: The initial concentration of CO2 is _________molar (3 s.f.) If -X is set equal to change in CO2, then the change of CO in terms of X is_______. The final concentration of CO2 is ________molar (3 s.f.) X is equal to _______molar. The partial pressure of CO2 is _________ atm and CO is __________atm, The Kp for the reaction at 1100 K is _______________, The number of moles of CO is _________moles (3 significant figures).

Answer 1

CO2(g) + C(s) <=> 2 CO(g)

CO2(g) + Ba(OH)2(aq) => BaCO3(s) + H2O(l)

Initial moles of CO2 = mass/molar mass of CO2

= 1.77/44.01 = 0.04022 mol

Final moles of CO2 = n(CO2) = moles of BaCO3 = mass/molar mass of BaCO3

= 3.41/197.34 = 0.01728 mol

Moles of CO2 reacted = initial - final moles of CO2

= 0.04022 - 0.01728 = 0.02294 mol

Moles of CO formed = n(CO) = 2 x moles of CO2 reacted

= 2 x 0.02294 = 0.04588 mol

Ideal gas equation: PV = nRT

P(CO2) = n(CO2) x RT/V

= 0.01728 x 0.08206 x 1100/1.000 = 1.560 atm

P(CO) = n(CO) x RT/V

= 0.04588 x 0.08206 x 1100/1.000 = 4.141 atm

P(total) = P(CO2) + P(CO)

= 1.560 + 4.141

= 5.701 atm = 5.70 atm

Kp = P(CO)^2/P(CO2)

= 4.141^2/1.560

= 10.99 = 11.0