if the ration of water drops to EDTA is 6.7 for the known sample and 10 for the unknown sample what is the concentration of the unknown sample? (The concentration of the known sample is 315 ppm)

a. 150mg/L
b. 210mg/L
c. 280mg?L
d. 320mg/L

  1. 👍
  2. 👎
  3. 👁
  1. I would set up a proportion.
    315ppm/6.7 = xppm/10
    and solve for x.

    1. 👍
    2. 👎
  2. that proportion solving for X doesnt give me a number listed as an option..I got 470

    1. 👍
    2. 👎
  3. I never liked the drops way of doing things. Having said that, I must take the blame and say I made a mistake.
    If it takes 3 drops of the EDTA for the known of 315 ppm and it takes only 2 drops for the unknown, the unknown must be weaker. You can do it by drops of EDTA (which makes more sense to me)
    315 x 2/3 = ??

    or you can use the ratio set up to give a smaller number; i.e.,
    315 x (6.7/10) = ?? ( you don't get the same number because the 6.7 was rounded off from 6.66667 to 6.7).

    or you can set up a ratio/proportion but the reverse of what I have above.
    I suppose it's obvious but I didn't even look at the options for answers; perhaps I should have looked.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    IN my experiment, I was doing a qualitative analysis of Group I and II anions using a flowchart. IN the chart I added 5 drops of 0.1M AgNO3 and several drops of 3M HNO3 to 5 drops of solution and found that a precipitate was

  2. Analytical chemistry

    A 25.0-mL solution of 0.0660 M EDTA was added to a 33.0-mL sample containing an unknown concentration of V3 . All V3 present formed a complex, leaving excess EDTA in solution. This solution was back-titrated with a 0.0450 M Ga3

  3. chemistry

    A 50.00-mL sample of groundwater is titrated with 0.0900 M EDTA. Assume that Ca2 accounts for all of the hardness in the groundwater. If 11.40 mL of EDTA is required to titrate the 50.00-mL sample, what is the hardness of the


    I have a pre lab questions that are due in a few hours and I need help. Theres several questions In the titration of 25.00 ml of a water sample, it took 20.590 ml of 4.995x10-3 M EDTA solution to reach the endpoint. The total

  1. Help me with science

    Use the table to answer the question. Sample Observation 1 The drop of food coloring spreads slowly. 2 The drop of food coloring spreads very quickly. A student places a drop of food coloring into two water samples. Her

  2. Chemistry (Re-post)

    A solution contains 1.694 mg of CoSO4 (MW 155.0) per mL. Calculate a) The volume of 0.008640 M EDTA needed to titrate a 25.00 ml aliquot of this solution. So this is my working out for this section, Step 1. Moles of CoSO4 =

  3. Chem 2

    A 100-mL sample of water is titrated with EDTA solutions in problem 2. The same amount of Mg2+ is added as previously, and the volume of EDTA required is 31.84mL. What volume of EDTA is used in titrating the Ca2+ in hard water?

  4. science

    if 50ml of a sample of hard water consumed 15 ml of 0.01M-EDTA.what is the hard ness of water

  1. Chemistry

    A student is given a sample in lab which contains one of the ions listed below. After adding a few drops ofsolution to part of the unknown sample, the student got a greyish precipitate. After adding a few drops ofsolution to

  2. science (chem)

    What would the best way to determine the organic layer from the aqueous layer in a extraction procedure? ~would it be to add a few drops of water to each layer and see what happens? or is there a better way since this procedure of

  3. chemistry

    25.00 mL aliquots of the solution from Part 1 are titrated with EDTA to the Eriochrome Black T end point. A blank containing a small measured amount of Mg2+ requires 2.60 mL of the EDTA to reach the end point. An aliquot to which


    n the titration of 25.00 ml of a water sample, it took 20.590 ml of 4.995x10-3 M EDTA solution to reach the endpoint. Complete the questions below: Calculate the number of moles of EDTA required to titrate the water sample. (enter

You can view more similar questions or ask a new question.