chemistry

posted by .

The concentration of calcium ions in hard water can be determined by titration with reagent X,which forms a complex with Ca2+(aq), giving a change of color. Three moles of X combine with one mole of Ca2+(aq). Since the color change in this titration is sensitive to pH, the titration has to be carried out in an alkaline buffer. A 25cm3 sample of hard water reacted with 24.0 cm3 of 1.00 x 10-4cm3 X(aq)
(a) What is the concentration, in moldm-3, of calcium ions in the hard water?
(b)The structure of X is similar to that of an amino acid. The way X acts as a ligand can be understood by considering how aminoethanoic acid, H2NCH2CO2H, forms coordinate(dative covalent) bonds with cations
(c)Explain why the complex formed betwwen aminoethanoic acid and aqueous calcium ions is more stable at pH10 than at pH4

  • chemistry -

    I think you have a typo here. I believe the 1.00 x 10^-4 cc X should be 1.00 x 10^-4 mol/dm^3 of X.

    24.0 cc X * 1.00E-4 mol/dm^3 = 0.0024 mmols X.
    Divide by 3 to obtain mmols Ca^2+ = 0.0008.
    a. (Ca^2+) = mmols/cc.
    b. no question.
    c.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry help-

    Which of the following has the lowest second ionization energy?
  2. Chemistry

    An ion exchange process may be used to remove ions causing hardness of water. Outline how this works. 1. Ca2+ and Mg2+ are the ions that cause the hardness of water, one example of softening the water is to react the hard water with …
  3. college

    0.02 g of CaCO3 is dissolved in 1 L of water. Calculate the moles of calcium carbonate that have dissolved in the water, the moles of Ca2+ ions in solution, and the number of Ca2+ ions in solution?
  4. Chemistry

    0.02 g of CaCO3 is dissolved in 1 L of water. Calculate the moles of calcium carbonate that have dissolved in the water, the moles of Ca2+ ions in solution, and the number of Ca2+ ions in solution?
  5. chemistry

    The urine excreted by an adult patient over 24 hours was collected and diluted to give 2.000L sample. at ph 10 EDTA FORMS 1:1 COMPLEX WITH BOTH Mg2+ and Ca2+ and after buffering at this pH a 10mL aliquot of the sample required 26.81mL …
  6. chemistry

    The urine excreted by an adult patient over 24 hours was collected and diluted to give 2.000L sample. at ph 10 EDTA FORMS 1:1 COMPLEX WITH BOTH Mg2+ and Ca2+ and after buffering at this pH a 10mL aliquot of the sample required 26.81mL …
  7. Chemistry

    Your muscles are switched on by releasing calcium ion from the sarcoplasmic reticulum that surrounds your muscle bundles. The Ca2+ binds to a muscle fiber, and that triggers the contraction. To relax the muscle again, Ca2+ must …
  8. Chemistry

    Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. …
  9. Chemistry

    Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. …
  10. Chemistry

    Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. …

More Similar Questions