Gravimetric Determination of Calcium ABSTRACT Determining the mass of a pure compound is a method of a gravimetric analysis. One of the gravimetric analyses is the precipitation; it is a method of separating the analyte from the unknown sample as a precipitate where it will be filtered and converted into a known composition that can be weighed to determine its mass (Skoog et al, 2013). Determining the mass of calcium by using gravimetric analysis was the objective of the experiment. A 25 mL of unknown sample was used to analyze its calcium component. This sample was diluted with 25mL of distilled water in a beaker. It was converted into a soluble precipitate by adding 25 mL of ammonium oxalate solution and 15 g of solid urea. Since …show more content…
We made sure to rinse the glass rod before removing it to the beaker. Then we added up 15 g of solid urea to each sample. We boiled the solution for 30 minutes up until the indicator turns yellow. After boiling, we filtered it each through a funnel. The remaining solid from the beaker will be transfer to the funnel by adding 3mL of ice cold water to the beaker. We made sure that all of the precipitate has been transferred. After that, we used 10 mL of ice cold water to rinse each beaker and pour the washings over the precipitate. We transferred the precipitate in to the petridish, but before that we weighted first the petridish with the filter paper so that we can get the grams of the CaC2O4 2H2O precipitate later. We dried the precipitate in an oven set at 105oC for 1 hour. After that, we placed it inside the desiccator for 30 minutes to cool down the heat. Then instantly we weigh the petridish with CaC2O4 2H2O precipitate. In order to get the weight CaC2O4 2H2O precipitate, we subtracted the mass of the petridish alone from the mass of the petridish with CaC2O4 2H2O precipitate. And for determining the weight of Ca in the CaC2O4 2H2O precipitate, we use stoichiometry. We also computed for the average weight of calcium. III. RESULTS AND DISCUSSION Sample No. Trial 1 Trial 2 Volume of sample analyzed, mL 25 mL 25 mL Weight of
First, we were to measure and record the mass of a beaker, then transfer about 1 gram of the salt mixture into the beaker, measure, and record the combined mass. Then, we had to fill a 400-ml beaker with deionized water and test it to make sure that the ph was just basic. We then combined the deionized water and salt by adding about 150ml of the deionized
As a group, we obtained our salt mixture of calcium chloride and potassium oxalate, and weighed the mixture. We were able to make an aqueous solution from the mixture and distilled water. We boiled and filtered off the solution, leaving the precipitate. Once the precipitate was dried overnight, it was weighed and the mass was measured. Then we calculated the moles of the precipitate.
In this task the concentration of an unknown sample of copper sulphate using colorimetry was used to find the concentration. In this investigation copper sulphate was used which is CuSO4.5H20 as a formula. To make a standard solution which was 1M, the same clean equipment was used to make up the standard solution as used to make sodium carbonate. However there was one difference and that was that the hot distilled water was used to dissolve the copper sulphate crystals. There had to be enough hot water in order to dissolve the crystals into the beaker and then add cold distilled water to cool the solution.
After added, pick up the beaker and swirl it around lightly for a short period of time.
Discard the solution in the appropriate container as directed to you by your lab instructor.
Fill a test tube about 1/3 full with cold tap water for use in step 34.
The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.
XII. Take the 250 ml beaker to your lab bench. Set up a gravity filtration with a plastic funnel, folded wet filter paper, and an Erlenmeyer flask. Pour the content in the 250 ml beaker slowly through the filter paper. Wash the filter paper with deionized water. Dispose of the filtrate in the proper labeled waste container.
1) Separate the solid from the liquid in the beaker by decanting the liquid. Ask your instructor to demonstrate the correct procedure.
The lab performed required the use of quantitative and analytical analysis along with limiting reagent analysis. The reaction of Copper (II) Sulfate, CuSO4, mass of 7.0015g with 2.0095g Fe or iron powder produced a solid precipitate of copper while the solution remained the blue color. Through this the appropriate reaction had to be determined out of the two possibilities. Through the use of a vacuum filtration system the mass of Cu was found to be 2.1726g which meant that through limiting reagent analysis Fe was determined to be the limiting reagent and the chemical reaction was determined to be as following:-
1.) Transfer the distillate to separatory funnel. Fluid didn’t seem very clear but sufficient to finish our lab on time.
Using the direct weighing and weighing by difference methods to find weight and mass of chemicals and compounds.
One milliliter of 6.00-M phosphoric acid was placed into a 125-mL Erlenmeyer flask using a volumetric pipette. Using a slightly larger pipette, six milliliters of 3.00-M sodium hydroxide was transferred into a 50-mL beaker. Then a disposable pipette was used to slowly mix the sodium hydroxide into the phosphoric acid while the solution was swirled around. Then both the beaker and flask were rinsed with 2-mL of deionized water and set aside. A clean and dry evaporating dish was weighed with watch glass on a scale. Then the solution was poured into the dish and the watch glass was placed on top. The solution was then heated with a Bunsen burner to allow for the water to boil off to reveal a dry white solid. After the dish cooled to room temperature it was once again weighed and the new mass was recorded.
Weigh out the necessary grams of Copper Sulfate Pentahydrate. The 40-degree group weighed out 40 grams. (See Figure 1)
Quantitative analysis is the determination of an amount present in a variety of settings. On the other hand, qualitative analysis is the determination of non-numerical information about a reaction, such as observing that a reaction results in a color change. There are chemical changes that separate cations and physical separations, such as decanting, where liquid is poured from a solid-liquid mixture, leaving the solid behind. Centrifuging is another separation technique, where a solid is separated from a liquid by whirling the mixture at high speed. A mixture of metal ions in a solution can be separated by a reaction of precipitation and in this experiment, the metal cations of aluminum, nickel, and iron ions will be separated from a solution