posted by .

what is the molar solubility of lead sulfate in 1.0 X 10^-3 M Na2SO4?

The Solubility Product Constant PbSO4

Ksp= 1.8 x 10^-8

The Ksp expression is:
Na2SO4 = [2Na][SO4^-2]


Ksp= 1.8 x 10^-8 = (x)(2x)
Ksp= 1.8 x 10^-8 /4x^3

1.8 x 10^-8/4 = x^3
4.5 x 10^-9 = x^3

is this right so far... what do i do next please

  • Chemistry -

    No, you have made some wrong assumptions. First, PbSO4 is the insoluble material. Na2SO4 is soluble in water. Second, this is a common ion problem in which the presence of the sulfate ion from Na2SO4 will decrease the solubility of PbSO4.

  • Chemistry -

    So what do i do then to solve for the ksp

  • Chemistry -

    The problem doesn't ask for you to solve for Ksp. It asks for the solubility of PbSO4 in 1 x 10^-3 M Na2SO4.

    PbSO4 ==> Pb^+2 + SO4^=

    Ksp = (Pb^+2)(SO4^=) = 1.8 x 10^-8
    If solubility of PbSO4 = S (or x if you wish), then (Pb^+) = S and (SO4^=) = S

    The Na2SO4 in solution is
    Na2SO4 ==> 2Na^+ + SO4^=
    Since it is 1 x 10^-3 M in Na2SO4, then (SO4^=) = 1 x 10^-3.

    Now set those up in the Ksp expression and solve for S. Remember that the total sulfate is that from the PbSO4 + that form the Na2SO4.

  • Chemistry -

    So im solving for two expressions... is that it.

  • Chemistry -

    ok I got x^2 = 1.8 x 10^-8 = 1.34 x 10^-4 for PbSO4 is this right

  • Chemistry -

    You are solving for the only unknown in the equation, which is S.
    Ksp = (Pb^+2)(SO4^-2) = 1.8 x 10^-8
    (S)(S + 1E-3)= 1.8 x 10^-8
    S =

  • Chemistry -

    i subtracted 1E-3 from the 1.8E-8 and it got me a -9.999E-4 then i took the sqrt cause (X)(X) is x^2 and then the calculator told me an error

  • Chemistry -

    Ksp = (Pb^+2)(SO4^=) = 1,8 x 10^-8
    (Pb^+2) = x
    (SO4^=) = x+0.001
    (x)(x+0.001) = 1.8 x 10^-8
    You can see that this is a quadratic equation and we could solve it as a quadratic. The exact solution is (and I'm switching to y so as not to confuse the x with the times sign),
    y^2 + 0.001y = 1.8 x 10^-8

    There are two ways to do this.
    1. Simplify the equation so there is no quadratic. You do that by making the assumption that y + 0.001 = 0.001; that is, that y is such a small number that a small number + 0.001 is still 0.001. If we do that then we have
    y = 1.8 x 10^-8/0.001 = 1.8 x 10^-5 M. We need to test to see if our assumption is ok. 0.001 + 1.8 x 10^-5 = 0.00102 and there is just a small difference so we let it go and work it the easy way.
    2. we can solve the quadratic by equating
    y^2 + 0.001 -1.8 x 10^-8 = 0
    I solved this by the quadratic formula and obtained 1.77 x 10^-5 so you see we don't make a bad assumption by solving it the easy way.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    Calulate the molar solubility of Al(OH)3 in water. (Ksp = 3 x 10^-34) Al(OH)3(s) ==>Al^+3 + 3OH^- Ksp = (Al^+3)(OH^-)^3 = 3E-34 Let x = molar solubility of Al(OH)3 then x molar = (Al^+3) and 3x molar = (OH^-) Plug in to Ksp and …
  2. chemistry

    Calculate the xolubility of calcium sulfate in 0.010 mol/L calcium nitrate at SATP CaSO4 ==> Ca^+2 + SO4^= Ca(NO2)2 ==> Ca^+2 + 2NO3^- = 0.01 M Ksp CaSO4 = (Ca^+2)(SO4^=) = ?
  3. Chemistry! URGENT!

    Calculate the solubility, in molL―1, of lead sulfate, PbSO4, in a 0.0185 M solution of sodium sulfate, Na2SO4 . Ksp (PbSO4) = 1.6 x 10―8 I get 8 x 10^-9...but that is not right! Thanks!
  4. chem

    The solubility product of silver sulfate is 1.6* 10^-5. What is the molar solubility of this compound?
  5. Chemistry

    Use the data in this table to calculate the solubility of each sparingly soluble substance in its respective solution. (a) silver bromide in 0.066 M NaBr(aq) mol ยท L-1 I know how to do this one, found it to be 1.167E-11 which is correct. …
  6. Chemistry

    The molarity of Sr2+ in a saturated solution of SrSO4 was determined to be 0.000500 M. Calculate the solubility product constant (Ksp) for SrSO4. SrSO4(s) = Sr^2+(aq) + SO4^2- (aq) Molar Mass (g/mol) SrSO4 183.68 This is what I know: …
  7. Chemistry

    Which of the following substances has the greatest solubility in water?
  8. chemistry

    what is the solubility of barium sulfate in a solution containing 0.050 M sodium selfate?
  9. Chemistry(Please check)

    What is molar solubility of Al(OH)3 at 25 degrees C given the solubility product Ksp = 5.0e-33?
  10. chemistry ksp

    i feel like none of these answers are right. if the solubility of the solid is 'S' mol/ L, what is the Ksp of the product of the salt?

More Similar Questions