56 WATER AND SOLUTION- How many grams of KNO 3 will be obtained in (F) after
cooling the filtrate from (E) to 10° and filtering? - How many grams of NaCl will be obtained in (F)1
- If (C) and (F) are now united and water added to make a
total of 100 grams of water, the whole heated to 100° and then
cooled to 10°, how many grams of KN0 3 will separate on cooling
to 10°? - How many grams of NaCl will separate from the solution in
Question 8 in cooling to 10°?
Materials: crude Chile saltpeter, NaN0 3 , 170 grams = 2 F.W.
crude potassium chloride, KC1,149 grams = 2 F.W.
Reagent: AgNO 3 solution.
Apparatus: 750-cc. casserole.
5-inch watch glass.
5-inch funnel,
perforated filter plate,
suction flask and trap bottle.
250° thermometer,
iron ring and ring stand.
Bunsen burner.Procedure: Place the NaN0 3 and KC1 in a 750-cc. casserole.
Add 210 cc. of water, cover with a watch glass, and place over a low
flame. While keeping watch of the casserole to see that its contents
do not boil, prepare a suction filter according to Note 4 (b) on
page 6. Then raise the flame under the casserole and watch it until
boiling commences. Lower the flame, and let the mixture boil
gently just 1 minute, keeping the watch.glass over the casserole
to retard evaporation. While it is at the boiling temperature pour
(see Fig. 1, page 5) the mixture from the casserole into the suction
filter. Quickly scrape most of the damp salt into the filter, and
cover the funnel with a watch glass to retard cooling. Do not
rinse out the casserole but reserve it with the adhering salt and to
it add the batch of crystals (A) as soon as they have been
drained from the hot liquor. Pour the filtrate (B) into a beaker,
and cool it to 10° by setting it in a pan of cold water or ice
water.
Stir the crystallizing solution so as to obtain a uniform crystal
meal which is easier to handle and drain on the filter than the