Gravimetric Determination of an Unknown Sulfate Flashcards
This is a quantitative method being used to determine the amount of a substance by selective precipitation of a substance from a solution
Gravimetric analysis
In gravimetric analysis, _______ is separated from the aqueous solution by means of filtration and is then weighed
Precipitate
In the experiment, the __________ of sulfate in an unknown sample is determined by gravimetry
Percentage mass
In gravimetry, the first step is to ___________
Pre-weigh the unknown sample and dissolve it in water
In gravimetry, the second step is the addition of ___________ to the unknown which will result in the precipitation of all the sulfate ions as barium sulfate
addition of barium chloride
Reaction involved in the experiment
Metal sulfate (aq) + barium chloride (aq) -> Barium sulfate (s) + metal chloride (aq)
In this experiment, what is collected through filtration, dried, and weighed?
Barium sulfate
True or false: Mass of sulfate in the precipitate = mass of sulfate in the unknown sample
True
3 reagents used in exp 13?
- unknown solid sulfate salt
- 6M HCl solution
- 0.1M BaCl2 solution
14 materials to be used in exp 13?
- 250 mL beaker
- analytical balance
- stirring rod
- 100mL graduated cylinder
- stand with ring clam
- wire screen
- bunsen burner
- wash bottle with distilled water
- crucible with cover
- crucible tongs
- ashless filter paper
- large funnel
- 250mL Erlenmeyer flask
- clay triangle
Step 1:
Measure between _____ and ___ g of the unknown sample in the balance
0.3, 0.5
Step 2:
Transfer it to a ____ beaker and add enough water to have approximately ____ ml in the beaker
- 250 mL
- 50 mL
Step 3:
Add 2mL of _____ and stir the solution until all the unknown sulfate has dissolved. Heat the solution until it is nearly boiling
6M HCl
Step 4:
Measure 15 mL of _______ and slowly add it to the unknown solution and stir the solution carefully. Allow the precipitate to settle in the beaker for 10 minutes
0.25M BaCl2
Step 5:
Weigh a ______ using the analytical balance and record its mass in the data sheet
filter paper
Step 6:
Fold the filter paper into ______ and open it into a cone and place it in the funnel
quarters
Step 7:
Dampen the filter paper with distilled water so it adheres to the cone of the funnel and slit the funnel over a ____________
250mL Erlenmeyer flask
Step 8:
Filter the solution into the _______
250mL (Erlenmeyer) flask
Step 9:
After ______, rinse any remaining barium sulfate precipitate in the funnel and remove the filter paper gently from the funnel by folding it on top of itself
filtration
Step 10:
Let the filter paper with the precipitate be completely air dried for at least ______ (time) before weighing again
a day
Step 11:
Weigh the ______ with the precipitate and record its mass in the data sheet
air dried filter paper
