Week 8
Studio 8a
AQ1: nitrate
See Table 2
F_06_S8a_AQ1_nitrate
Napthylamine Hydrochloride
Reagent: (need 20 mL per
student group) Dissolve 1 mL
concentrated HCl in 50 mL
deionized water. Then dissolve
0.60 grams 1-napthylamine in the
solution and stir for 15 minutes.
Transfer to 100 mL volumetric
flask and dilute to the mark.
Store in a refrigerator or ice bath
in a brown bottle; the solution is
stable for 1 week.
Possibly make nitrate
standard
IS 8
Studio 8b
Precipitation Reactions
Aqueous case study
Studio 8c
AQ2: chloride
Clear well plates
8 dropper bottles of 0.1M
solutions of NH4NO3
KNO3
Ca(NO3)2
Sr(NO3)2
Mg(NO3)2
Al(NO3)3
Fe(NO3)3
NaCl
NaClO4
NaOH
Na2CO3
Na2SO4
Na3PO4
1 dropper bottle of 0.1M
AgNO3
(perform demo of AgNO3 +
NaCl note coursepack says
Ag3PO4)
See Table 1
F_06_S8b_precipitation
F_06_S8c_AQ2_chloride
Table 2: Supplies for Week 6, Lab 2 (Amounts per section?)
Chemicals
Supplies Needed
Supplies we have
Concentrated 2
1- 500mL amber
HCl
7647-01-0
mL
bottle
2.4 M 140 mL
12-plastic bottles
HCl
7647-01-0 that will hold 100
mL
Finely powdered
6-10 mL glass vials
zinc
7440-66-6
1g
with caps
1-napthylamine
1.2 g
134-32-7
potassium nitrate 3g
7757-79-1
sodium acetate
0.20 M 140 mL
127-09-3
sodium chloride
200g
7647-14-5
sulfanilic acid (4- 0.03464 M* 140
(H2H)C6H4SO3H) mL
121-57-3
173.19 g/mol
Unknown
*Dissolve 0.60 g dry dulfanilic acid in 70 mL hot water dilute to 100 mL in volumetric flask
Napthylamine Hydrochloride Reagent: (need 20 mL per student group) Dissolve 1 mL
concentrated HCl in 50 mL deionized water. Then dissolve 0.60 grams 1-napthylamine in the
solution and stir for 15 minutes. Transfer to 100 mL volumetric flask and dilute to the mark.
Store in a refrigerator or ice bath in a brown bottle; the solution is stable for 1 week.
Zinc NaCl Mixture: (need about 20 g per student group) Mix 200 grams of granular NaCl with
1.00 gram of finely powdered Zinc. Mix the two powders thoroughly by shaking in a flask for
several minutes.
Stock Potassium Nitrate Solution:
Stock A: (500 ppm NO3-) Dry 2-3 grams KNO3 at 120C for 1 hour. Cool in a desicator.
Dissolve 0.816 grams of the dried KNO3 in 500 mL deionized water and dilute to 1 L.
Stock B: (100 ppm NO3-) Pipet out 50 mL of Stock A solution and dilute to a volume of 250 mL
in a volumetric flask to produce the stock 100 mg/L standard that will be used throughout the
experiment. Need 100-150 mL per student group.
Hydrochloric Acid Reagent: (need 20 mL per student group) Dilute 100 mL concentrated HCl to
500 mL with water and mix thoroughly.
Sulfanilic Acid Solution: (need 20 mL per student group) Dissolve 0.60 grams dry sulfanilic
acid in about 70 mL of hot water. Once dissolved, dilute the sulfanilic acid solution to 100 mL in
a volumetric flask and mix thoroughly.
Sodium Acetate Solution: (need 20 mL per student group) Prepare 100 mL of sodium acetate
solution by dissolving 16.4 grams of sodium acetate in 5 mL deionized water and diluting to 100
mL mark with DI water.
Well Water Unknown: (Conc: 50 ppm NO3-, need 50 mL per student group). Add 10 mL of the
KNO3 Stock A solution (500 ppm) to a 100-mL volumetric flask, dilute to the mark with H2O.
Students prepare a primary standard solution of NaCl and use it to standardize the AgNO3. Then
they test for chloride ion concentration through a precipitation titration with potassium chromate
as the indicator.
Table 1: Week 7, lab 2 chemicals needed
Chemicals
1.9 L (0.0025M) this is a standard solution so accuracy is
7761-88-8
very important. (in at least 2 bottles)
K2CrO4
140 mL (0.014M) (in 4 bottles)
7789-00-6
Unknown 1.5 L
“septic
55 ppm Cl-**
system
effluent”
Reagents per 24 student section
** Add 0.9068 g dried primary standard NaCl to a 100 mL volumetric flask and dilute to the
mark. Pipet 10 mL of this solution into a 1.00 L volumetric, dilute to the mark with DI
water. This solution doesn’t have to be exact, but in the range of 55 ppm. +/- 10 ppm.
AgNO3