Determination of the Solubility Product Constant for Calcium Sulfate: the Effect of Ionic Strengths of Electrolyte Solutions

In this experiment, it is very important to ensure that the deionized water is just basic and not acidic in order to obtain accurate results. Calcium oxalate does not precipitate in an acidic solution because of the formation of H2C2O4-, an ion that does not precipitate with Ca2+ . Allowing the precipitate to settle is also very

The mixture was heated at 120°C using an aluminum block and was stirred gently. After all of the solid dissolved, it was heated for 20 additional minutes to ensure the reaction was complete.

The wet, crude product was placed into the 50 mL Erlenmeyer flask. Small amounts of CaCl2 were added to dry the solution. The flask was sealed and the mixture was swirled and left to settle. Once

This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

We will observe the reaction of a buffer solution with added acids or bases. We will then evaluate buffering capacity in response to additions added from dilute acid and bases to the buffer.

Purpose: In this lab, we will calculate the percent composition of water in a hydrate and determine the empirical formula of the hydrate.

After 10 minutes, it was put on a vacuum filtration apparatus. The weight of the residue was recorded. 10. After, Na2SO4 was added to the separatory funnel and left for 5 minutes while occasionally mixed. The residue was taken out.

The experiment required an average of 18.98mL of the 0.050M HCl solution to carry out the reaction and trigger the indicator. With the volume, the concentration of the OH- was determined to be .038M, and the concentration of the Ca2+ was determined to be .019M. With the concentration of the OH- and the Ca2+ known, the Ksp was determined to be 3.11x10-5 . Ksp is used to determine the solubility of a substance in a solvent. In the experiment, the substances the solubility is being found on is undissolved calcium hydroxide.

For Standard solution 1, we added 2 mL stock solution with 8 mL DI water

The ratio of the moles of water to copper (II) was 4.77, rounded to 5, proving that copper (II) sulphate pentahydrate does in fact have a ratio of 5 water moles to 1 copper (II) sulphate mole. The hydrate salt copper (II) sulphate pentahydrate is composed of 65.00 % of copper (II) sulphate and 35.00% of water using the measured data. The composition using defined values is 36.08% water and 63.92% of copper (II) sulphate. There is a slight error between the values. One of the possible reasons could be the moisture of the atmosphere of the air, which prevented the water of the hydrate from fully evaporating. Though some bonds between the water molecules were broken and evaporated from the compound, the copper (II) sulphate may have formed bonds

A total of 2-mL of glacial acetic acid was added to the vial. Three drops of concentrated H2SO4 and a boiling chip were added to the vial. The vial was attached to a clamp and rested in a sand bath that ranged between 150-160°C. A cold, damp kim wipe was placed around the tip of the vial to act as a condenser. The mixture was refluxed for one hour. Once the hour passed, the reaction mixture was cooled to room temperature and the sand bath was turned off. After the boiling chip was removed from the vial, 1-mL of 5% sodium hydrogen carbonate (NaHCO3) was slowly added to the reaction mixture, capped and swirled. The vial was shaken to mix the contents and the cap was removed to release the pressure. This was repeated until the bubbles were no longer produced. A Pasteur pipet was used to remove the aqueous layer which was disposed in a test tube labeled “Aqueous Layer”. The extraction of the upper organic layer was repeated two more times with new 1-mL portions of 5% NaHCO3, placing the aqueous layer in the labeled test tube each

After centrifugation, the volume of each CFE was measured, and then per every mL, .39 grams of ammonium sulfate was weighed out. The CFE was then placed in a beaker that was suspended on top of ice in a larger beaker, which was placed on top of a stir plate. Over a course of 20 minutes, ammonium sulfate was added to the CFE while stirring slowly. After the completing adding all of the ammonium sulfate, solution was stirred for an addition 15 minutes. Followed by centrifugation at 15000 RPM for 20 minutes.

In order to test this, method of serial dilution was first utilized to find the amount of buffer solution needed for the

This was set aside for a water bath later in the experiment. 13.8 g of salicylic acid followed by 14mL of acetic anhydride is combined to a 125mL Erlenmeyer flask. Eight drops of concentrated H2SO4 was added to the Erlenmeyer flask that housed the salicylic acid and acetic anhydride. The contents were then gently swirled and transported to the hot water bath created earlier. The heat from the water bath and occasional mixing of the contents quickly dissolved the powder contents. The flask was then removed and combined with 40mL of cold distilled water. The flask was then placed into an ice bath to create a slush-like substance. A vacuum filtration system was assembled and the slush was washed three times with distilled water. The product was left to dry in lab drawer for seven

In this experiment, we first prepared three dilution of the calcium carbonate solution (CaCO3(aq))with a concentration of 0.01, 0.05 and 0.1 in different graduated cylinder. Each dilution had two samples of 20ml each. Hence, each dilution had two test results and their average is counted as the final result.