Chemistry

posted by .

You weigh out 196.07mg ferrous ammounium sulfate (FW 392.14) to prepare 250mL of solution which is 0.002M with respect to that compound. The salt is quantitatively transferred into a 250mL volumetric flask and 8mL of 3M H2SO4 is added and then diluted to the mark (call this stock Fe solution). 10mL of the stock solution is pipeted into a 100mL volumetric flask, adding 4mL of 3M H2SO4 and diluted to the mark (call this original Fe solution).

10mL of the original fe solution is pipeted into a 50mL volumetric flask (call this standard Fe solution). What is the concentration of the standard Fe solution (mg/L)?

It should be somewhere around 2, but I can't seem to calculate it correctly.

  • Chemistry -

    You weigh out 196.07mg ferrous ammounium sulfate (FW 392.14) to prepare 250mL of solution which is 0.002M with respect to that compound.
    The salt is quantitatively transferred into a 250mL volumetric flask and 8mL of 3M H2SO4 is added and then diluted to the mark (call this stock Fe solution).


    So this 250 ml solution is

    784.28 mg L^-1 (as FAS hydrate)
    0.00200 M
    112 mg L^-1 as Fe




    10mL of the stock solution is pipeted into a 100mL volumetric flask, adding 4mL of 3M H2SO4 and diluted to the mark (call this original Fe solution)

    Here we have dilutes by a factor of 10

    So this 100 ml solution is

    78.428 mg L^-1 (as FAS hydrate)
    0.000200 M
    11.2 mg L^-1 as Fe

    10mL of the original fe solution is pipeted into a 50mL volumetric flask (call this standard Fe solution).

    I presume this is made to the mark? In which case there is a further dilution by a factor of 5.

    15.69 mg L^-1 (as FAS hydrate)
    0.0000400 M
    2.24 mg L^-1 as Fe

    So perhaps the question is looking for the Fe concentration in mg L^-1?

    (You should check my figures as I have rounded in places)

  • Chemistry -

    Um, exactly how did you calculate the 112 mg L^-1 as Fe, 11.2 mg L^-1 as Fe and 2.24 mg L^-1 as Fe ?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    o prepare a 200 mL of aqueous stock solution X, you transferred 50 mL of a known concentration solution into a 200 mL volumetric flask. If you realize that the volumetric flask was contaminated with water droplets after you cleanly …
  2. CHemistry

    In a clean 250mL volumetric flask, 125mL of a 6.0 M hydrochloride acid was added. This was then diluted with more water to reach the 250mL mark. What is the molarity of the acid at this time?
  3. chemical principal

    a chemist weidghed 1.25g of sodum hydroxide ,placed it in a volumetric flask and then added enough deionized water to bring the total volume to 250mL. How many moles of NaOH were added to the volumetric flask
  4. Analytical Chemistry

    How do I find the mass of KHP? 0.5050 grams of KHP was used and placed into a 250mL volumetric flask and diluted to the mark with distilled water. 50.00mL of this KHP solution was placed in a 250mL beaker. It took 14.75mL of 0.0067M
  5. Chemistry

    Solution A is 2.40M. 20mLs of solution A is transferred to a 250mL volumetric flask and diliuted to volume with water. What is the concentration of the diluted solution?
  6. Chem 1

    Suppose 1.624g of salt FeSO4 is placed in a 250mL flask to which 50mL of water and 10 mL of 3M H2SO4 are added. How many mL of .1062 M KMnO4 solution are required to reach the endpoint?
  7. Chem 1

    Suppose 1.624g of salt FeSO4 is placed in a 250mL flask to which 50mL of water and 10 mL of 3M H2SO4 are added. How many mL of .1062 M KMnO4 solution are required to reach the endpoint?
  8. Chemistry

    You are a work study student in our chemistry department. Amy, your supervisor has just asked you to prepare 250ml of 2.00M H2SO4 solution for tomorrow's undergraduate experiment. The Stock Solutions cabinet is under the Stockroom …
  9. chemistry

    How to prepare 0.2M of NaOH in 250ml volumetric flask?
  10. quant chemistry

    A standard solution of Mn2+ was prepared by dissolving 0.250 g of Mn in 10 mL of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was quantitatively transferred to a 100 mL volumetric flask and diluted …

More Similar Questions