Sodium carbonate, Na₂CO₃(s), can be prepared by heating sodium bicarbonate, NaHCO₃(s) as shown below.2NaHCO₃(s) (⇌) Na₂CO₃(s) + CO₂(g) + H₂O(g) K_p = 0.23 at 100ºC If a sample of NaHCO₃ is placed in an evacuated flask and allowed to achieve equilibrium at 100ºC, what will the total gas pressure be

Question

Quizplus · Accepted Answer

Using the equilibrium constant expression: Kp = P(CO2) * P(H2O) / P(Na2CO3) Since the flask is evacuated, the initial pressures of CO2 and H2O are both 0. Let x be the change in pressure of NaHCO₃ and CO₂ at equilibrium. Therefore, the equilibrium pressures of NaHCO₃, CO₂, and Na2CO3 are (0.23 + x), x, and 0, respectively. Substituting these into the equilibrium constant expression and solving for x gives: 0.23 = x^2 / (0.23 + x) x = 0.185 atm Therefore, the total gas pressure at equilibrium is: 0.185 + 0 + 0 = 0.185 atm (since the pressure of Na2CO3 is 0) Adding this to the initial pressure of CO₂ gives: 0.185 + 0 = 0.370 atm And since two moles of CO₂ are produced for every mole of NaHCO₃ consumed, the total gas pressure is doubled to give the final answer of: 2(0.370) = 0.740 atm, which is approximately 0.96 atm (rounded to two decimal places).

Sodium Carbonate, Na2CO3(s), Can Be Prepared by Heating Sodium Bicarbonate

Sodium Carbonate, Na₂CO₃(s), Can Be Prepared by Heating Sodium Bicarbonate