Solubility Product Constant
Objective: To determine in the laboratory the solubility constant
(Ksp) of Calcium Sulfate(CaSO4)
Materials and Instruments
* Burette
* Pipette
* Clamp
* Glass rod
* Digital balance
* Teflon stopper
* Stopcock
* Erlenmeyer flask
* Sheet of black paper
* 100mL Graduated cylinder
* 0.050 M CaCl2
* 0.050 M Na2SO4
* Distilled water
Procedure:
1. With the Molarity formulua, calculate how many gr of CaCl2 are
needed in order to form a 0.050 M CaCl2 solution with 500 mL of
water
2. Repeat the calculations with the right numbers for Na2SO4
3. Weight the compounds, separately, and get the amount you need
in order to prepare your solution
4. Prepare both solutions. Mix the indicated weight of each
compound with 500 mL of water. Use different flasks for each
compound
5. With the graduated cylinder measure 100 mL of 0.050 CaCl2. Pour
solution into the flask.
6. Fill a clean, dry burette with 0.050 M Na2SO4. Drain burette
until no bubbles are left in the tip. Record the initial volume
of Na2SO4 of the burette in a data table
7. Lay a sheet of black paper beneath the burette, place the flask
with the CaCl2 solution on top
8. Add Na2SO4 to the flask from the burette and gently swirl the
flask.
Each subsequent trial will use one gram more. 2.Put baking soda into reaction vessel. 3.Measure 40 mL vinegar. 4.Completely fill 1000 mL graduated cylinder with water.
Record the volume of the sodium thiosulfate solution used in the titration, and repeat the procedure in a duplicate titration.
The purpose of the experiment was to find which balanced chemical equation best represents the thermal decomposition of sodium bicarbonate, or baking soda (NaHCO3). The lab presented us with four possible equations but there was no way of determining which equation was correct unless we performed an experiment and using the law of conservation of mass which says that mass is conserved during a chemical reaction, the law of definite proportions which says that a compound is always made of the same proportion of elements by mass, and stoichiometry to properly balance the equation.
The purpose of the experiment was to determine the solubility of calcium sulfate. In Part A with the resin, The number of moles in the original CaSO4 sample was determined to be 3.69 x 10-4 moles, and the molarity of calcium in the saturated CaSO4 solution was determined to be 0.0148 M. The molarity of calcium in the saturated CaSO4 solution is equal to the solubility of CaSO4, so the solubility of CaSO4 was determined to be 0.0148 M at 18.9 °C. In Part B with the titration using EDTA, the moles of calcium in the original saturated calcium sulfate solution was determined to be 3.87 x 10-4 moles in Trial 1 and 3.74 x 10-4 moles in Trial 2, so the molarities of calcium in the saturated solution were determined to be 0.0155 M in Trial 1 and 0.0150
3. Add on of the following volumes of distilled water to the test tube, as assigned by your teacher: 10.0mL, 15.0mL, 20.0mL, 25.0mL, 30.0mL. (If you use a graduated cylinder, remember to read the volume from the bottom of the water meniscus. You can make more a more accurate volume measurement using either a pipette or a burette.)
A known solution of Na2SO4 was made and the unknown solution was made. Both solutions were mixed with BaCl2 twice to create a reaction. The solutions were all put into test tubes to be put into the centrifuge to separate out the precipitate, NaCl. The precipitate was then removed from the tubes and put on filter paper to dry. Once they dried the filter paper with precipitate was weighed. Then the mass of the filter paper was subtracted from the total weight, to find the mass of the precipitate, shown in Table 3. The mass of NaCl precipitate was used to find the amount of NaCl present. Then the amount of NaCl was used to determine the amount of Na2SO4 present. Then this number was used to determine the experimental molar mass of Na2SO4. The experimental molar mass was compared to the actual molar mass. All the values of these calculations are shown in Table 5. The actual molar mass and experimental molar mass were very close and resulted in a percent yield of
Put the amount of 0.1M cobalt (II) chloride hexahydrate that fills the end of a spatula into a test tube. Then add 2mL of 95% ethanol. Tap the end of the test tube to mix the solution and record the pertinent data in section 1 of the Data Table. Discard the solution in the appropriate container as directed to you by your lab instructor.
NaCl solution varies between freshwater that has a concentration of 0.005% salt and ocean water that has a concentration of 3.5% salt. I am using the NaCl solution in four different concentration levels, NaCl 0% (distilled water), NaCl .375%, NaCl .75% and NaCl 1.5%.
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
Discussion: The results acquired from the experiment have supported the hypothesis. In the first sample, red blood cell in the isotonic solution (NaCl 0.85%) kept its regular shape. This is because when RBC was placed in an isotonic solution, which is the solution has the same concentration of solutes as the cell, water will move into and out of the cell simultaneously and no net effect will be seen. In the second sample, cell shrank, and crenation occurred in the hypertonic solution (NaCl 10%) because the hypotonic solution has a higher osmosis pressure than the cell, water is going to escape from the cell for decreasing the high concentration of solute in the hypotonic solution. Lastly, in the hypertonic solution (NaCl 10%), cell bloated,
This paper is about the calculation of standard thermodynamic properties of the four solid solutions in the phase diagram of Ag2S – Ag2Se. They calculated these properties using the model of regular and subregular solutions. The four solid solutions are: a restricted fcc solid solution (γ- Ag2S-Ag2S1-xSe (x<0.3)), a complete bcc solid solution (β- Ag2S – Ag2Se), monoclinic solid solution (α) from Ag2S to Ag2S0.4Se0.6, and a orthorhombic solid solution (α) from Ag2S0.3Se0.7 to Ag2Se. There is also a miscibility gap between Ag2S0.4Se0.6 and Ag2S0.3Se0.7. In this region Gmix and Smix have been calculated using subregular model for asymmetric solutions.
11.) Subtract the mass of the evaporating dish from the mass of the evaporating dish and it's contents. Multiply that number by 10 to get the solubilty in grams per 100 cm3 of water.
2. In the large beaker, put water and boil it completely. After that, remove the beaker from heat. 3. Sample tubes (A-D) should be labeled and capped tightly.
Remove the extra solvent on a steam bath under a hood while flushing the flask with N2 gas, leaving the crude extract. Weigh extract.
second test tube also add 6 mL of 0.1M HCl. Make a solution of 0.165