Chemistry

posted by .

HCONH2(g) <-> NH3(g) + CO2(g) Kc= 4.84 at 400 K2(g)

If 0.186 mol of HCONH2(g) dissciates in 2.16L at 400K, what will be the total pressure at equilibrium?

  • Chemistry -

    ............HCONH2 ==> NH3 + CO2
    initial.....0.186 mols..0.....0
    change.......-x.........x......x
    equil.......0.186-x.....x......x

    Substitute the above ICE chart into the Kc expression for the reaction and solve for x. That will give you moles NH3 and moles CO2. Add the moles together and substitute into PV = nRT to solve for pressure.

  • Chemistry -

    When I am solving for X my formula comes out to be

    4.84 = X^2/ (.186-X)

    Can I assume that x << .05 and eliminate it from the denominator and just solve for the equation 4.84 = X^2/.186?

  • Chemistry -

    No, you may not make that assumption; however, I may have made an error. Let me think about this awhile. I'll post something different and erase what is there now or post a note that the original response stands.

  • Chemistry -

    Okay thanks so much.

  • Chemistry -

    OK. I made an error and the problem can't be solved that way. First, we convert moles to molarity.
    (HCONH2) = 0.186/2.16L = 0.08611M

    ............HCONH2 ==> NH3 + CO2
    initial.....0.08611M....0.....0
    change.......-xM.........xM......xM
    equil......0.08611-x M.....xM....xM

    Substitute the above ICE chart into the Kc expression for the reaction and solve for x. That will give you M NH3, M CO2 and M HCONH2. Convert M to moles for each (M x L = moles), add the moles together and substitute into PV = nRT to solve for pressure. I will leave the original post there for the time being so you can make comparisons if you wish; however, I'll erase it before I go to bed tonight. I don't like to leave incorrect posts on the board.

  • Chemistry -

    Ok thanks so much.

    So when I solve for X I got

    4.48(0.086 - x) = x^2
    0.385 - 4.48x - x^2 = 0

    Now i'd substitute that into the quadratic formula? Or is there an easier way to solve for X?

  • Chemistry -

    That K is 4.84 and not 4.48 so you need to redo that part. When you solve that quadratic that gives you x (and I don't know of an easier way to do it.) Most calculators now have that built in to solve those things. I programmed mine to do that. That gives you x, use that to determine (HCONH2), (NH3), and (CO2), convert concns to moles, add the moles to find the total, then use PV = nRT to solve for P.

  • Chemistry -

    Ok this helps so much. Thanks a lot I appreciate it.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry, plz check work

    NH3+H2S-->NH4HS <-- Kc=400 at 35 Celsius what mass of NH4HS will be present at equilbrium?
  2. chem

    The following reaction is used in some self-contained breathing devices as a source of O2. 4KO2(s) + 2C02(g)---> 2K2CO3(s) + 3O2(g) Suppose that a sample of CO2(g) is added to an evacuated flask containing KO2(s) and equilibrium …
  3. Chemistry

    Which temperature change would cause the volume of a sample of an ideal gas to double when the pressure of the sample remains the same?
  4. Chemistry

    Consider the following equilibrium: NH4Cl(s)--->NH3(g) + HCl(g) Suppose a vessel containing NH4Cl(s), NH3(g) and HCl(g) is at equilibrium. If the volume of vessel is instantaneously doubled while keeping the temp constant when a …
  5. Chemistry

    Consider the heterogeneous equilibrium process shown below. C(s) + CO2(g) 2 CO(g) At 700.°C, the total pressure of the system is found to be 3.87 atm. If the equilibrium constant KP is 1.52, calculate the equilibrium partial pressures …
  6. chemistry

    Dinitrogen tetroxide decomposes to form nitrogen dioxide in a second order reaction: N2O4(g)-> 2NO2(g) At 400K, the rate constant for this reaction has been measured to be 2.9x10^8 L/mol*s.suppose 0.222 mol of N2O4(g) is placed …
  7. AP Chem

    (NH4)2CO3 <-> 2NH3 + CO2 + H2O solid (NH4)2CO3 is placed in an evacuated container at 115C. When equilibrium is reached Kp = 1.93x10^-3. Extra NH3 gas is added, when equilibrium is reestablished, the partial pressure of NH3 is …
  8. umuc

    For the reaction HCONH2(g) NH3(g) + CO(g), Kc = 4.84 at 400 K. If ΔH° for this reaction is 29 kJ/mol, find Kc at 500 K.
  9. chem12

    1.0 mol of each of the gases, CO, H20, CO2 and H2 are placed in a 2.00L container and allowed to reach equilibrium. It is found at equilibrium 0.40 mol of CO is present. Calculate the value of K eq for the system. C0(g) + H20(g)--- …
  10. chem 12

    1.0 mol of each of the gases, CO, H20, CO2 and H2 are placed in a 2.00L container and allowed to reach equilibrium. It is found at equilibrium 0.40 mol of CO is present. Calculate the value of K eq for the system. C0(g) + H20(g)--- …

More Similar Questions