Name

Group

Section

/ /

H1

/ /

H2

ENABLE EDITING BEFORE FILLING OUT THIS FORM. IF YOU DON’T, THE FORMATTING WILL BE WRONG.

Report Due by 11:59 PM, March 9, 2018.

Email the completed report to . Use the link on the web page for this lab – it will insert the correct subject line for you.

Follow the guidelines for submitting this report. You can find a link to the guidelines for this lab on the website @ http://www.thelapierres.com/chm202/labs.html. Failure to follow directions will result in substantial point deductions.

Submission time will be determined by the time stamp on the email message.

Grade:

Lab average to date:

Overall average to date:

Results:

1.  Total Dissolved Solids in Water Samples (10 pts)

Sample # / Brand of Sample / Relative amount of Solids/Comments
1 / Distilled Water
2
3

Preparation of EDTA solution (10 pts)

Grams of EDTA required

Mass of EDTA
(Analytical Balance) / Mass of 250 mL flask
(Top Loading Balance)
Tare mass
Gross mass
Net mass

moles of EDTA mass of water

Concentration of EDTA (use correct units and number of significant figures!) (10 Pts)


Molarity (M)

Molality (m)

Mole fraction

Percentage (m/v)

2.  Quantitative Determination of Calcium Ion in Water Samples by EDTA Titration (40 pts)

Dist. Water / Sample 1 / Sample 2
Trial number / 1 / 2 / 3 / 4 / 5
Brand Name / N/A
Sample Volume (25.00 or 10.00 mL)
Initial Volume
(Vo)
Final Volume (Vf)
Net Volume
mol EDTA
molarity Ca2+
Water Hardness

Questions (total of 30 pts)

1.  Answer the following by referring to your results of the titrations. Your answers must be supported by your data.

a.  Which of the water samples that you tested had the highest calcium concentration? (5 pts)

Highest Ca2+ concentration
Lowest Ca2+ concentration

b.  Does this correlate with the total dissolved solids results you obtained? (5 pts)

c.  Which of your water samples was the purest? (5 pts)

d.  Was this what you would have predicted before the laboratory session? Why or why not? (5 pts)

2.  Why is hard water undesirable for some household and industrial uses? Explain the problem(s) encountered with using very hard water in these applications using chemical equations. This may require a little research. (10 pts)