posted by .

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^=) = ??. Look up Ksp for CaSO4.

Subsitute 0.01 for Ca^+2 and x for SO4^= and solve for solubility CaSO4. Post your work if you get stuck.

Ksp is 7.1 x 10^-5 for CaSO4

7.1x 10^-5 = (0.01)(x)

x = 0.000071/0.01


Why am I wrong?

  • chemistry -

    (Ca^+2) = x from CaSO4 and 0.01 from Ca(NO3)2.
    (SO4^=) = x
    (0.01+x)(x)=7.1 x 10^-5
    When you solved for x, the value of 0.0071 you have is correct; however, in relation to 0.01, it is too large. In other words, the total Ca^+2 is 0.01 + solubility of CaSO4. If the solubility (in this case x) is larger than about 5% of the common ion (0.01 in this case), you can't make the simplifying assumption that 0.01+x = 0.01. For example, you found 0.0071 for the solubility and that + 0.01 = 0.0171 which is MUCH MUCH greater than 5%. Therefore, a large error is made by making the simplifying assumption. What does that mean for you (and the problem)? It must be solved by the quadratic formula.
    (x+0.01)(x) = 7.1 x 10^-5
    x^2 + 0.01x -7.1 x 10^-5 = 0
    Make sure that the value of Ksp you are using is from the same source as your problem for if you are using a different Ksp than the person who put all those numbers in the data base you are checking then you may NEVER get the right answer. To let you know if your solution is correct or not, assuming Ksp really is 7.1 x 10^-5 (its about 5 something x 10^-5 in my references), I find solubility = 0.0048 M. Let me know if you have trouble.

  • chemistry -

    thank you

  • chemistry -

    i beat lindan in previous china open superseries hurray

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions


    How many moles of Calcium chloride can be added to 1.5L of 0.020potassium sulphate before a precipitate is expected?
  2. Chemistry (urgent)

    Hi, I have a few chemistry problems that I'm having trouble solving. I put my attempted solutions after the problems in *'s. There was one problem I had no idea how to solve. What concentration of silver chromate (Ksp = 9.0 x 10-12) …

    A saturated solution of CaSO4(aq) is made in a beaker until there is excess calcium sulfate resting at the bottom. Then solid potassium sulfate is added. Which of the following is true?
  4. chemistry

    you made up a standard solution of calcium sulfate (CaSO4). the temperature is 25C. you then add 5.00*10^-3 odium sulfate (Na2SO4). Calculate the concentrations of calcium and sulfate after equilibrium is reached?
  5. Chem

    You made up a saturated solution of calcium sulfate (CaSO4). The temp is 25 degrees Celsius. You then add 5.00*10^-3 of sodium sulfate (NaSO4). What are the concentrations of calcium and sulfate after equilibrium is reached?
  6. Chemistry 12

    The molar solubility of calcium sulphate CaSo4 is 8.43 x 10-3(10 to the power of negative 3) M. Calculate the mass of solid CaSo4 which can be evaporated from 250.0 mL of a saturated solution of CaSO4.
  7. Chem

    The solubility of calcium sulfate is1.90g of caso4 per liter of aquences solution at 25c. The formula weight of caso4 is 136.11 calculate the solubility product of caso4.
  8. Chemisty-Dr.Bob222

    Determine the minimum concentration of the precipitating agent on the right to cause precipitation of the cation from the solutions to the left. a. 0.035 M BaNO3; NaF b. 0.085 M CaI2 ; K2SO4 c. 0.0018 M AgNO3 ; RbCl My work: Are my …
  9. chemistry

    Given the following solubility constants, which list arranges the solutes in order of increasing solubility?
  10. chimistry

    What is the solubility of calcium sulfate (CaSO4) in 0.30 M aqueous sodium sulfate (Na2SO4)?

More Similar Questions