Purpose: Finding the concentration of Ca2+ ions in two samples of hard water. Hypothesis: According to the given molarity of CaCl2 in the table, the concentration of sample one should be 0.400 M, making the hardness of the water 400 mg/L and the concentration of sample four should be 0.100 M, making the hardness of the 40.1 mg/L. Procedures: The first experiment was performed to test the procedure of finding Ca2+ ions in a solution. A known amount of CaCl2 and an excess of Na2CO3 were added to a beaker with deionized water in order to make CaCO3 precipitate. The theoretical yield of CaCO3 was calculated from the mass of the CaCl2. The precipitate was filtered from the solution using the Buchner funnel and aspiration filtration. The precipitate was dried in the oven until the mass stopped decreasing. Then the mass of the funnel with filter was subtracted from the mass funnel, filter and precipitate to find the mass of the dry precipitate. In the tests of samples one and four, the molarity of CaCl2 was approximately known and it was tested using the same process of precipitating CaCO3 by adding excess Na2CO3 and determining experimental molarity of CaCl2 from the mass of that precipitate. After the first experiment to test the …show more content…
mL) x (1 mol Na2CO3 / 1 mol CaCO3) x (1000. mL Na2CO3 / .50 mol Na2CO3) = 4.0 mL, 4.0 mL (1.2) = 4.8 mL (0.200 g x 1 g / 1000. mg) / (.0200 L) x (1/100) = 40.1 mg/L Experimental Water Hardness (with classification) and Percent Yield mg/L = ppm Sample One: (mass of funnel and precipitate 16.37 g)-(mass of funnel 15.48 g)= (mass of CaCO3 precipitate 0.89 g) 0.89 g / .801 g = 110% yield 0.89 g x (1000 mg / (1 g x 20. mL) x (1000mL / 1 L) x (1/100) = 450 mg/L Very hard Sample Two: (mass of funnel and precipitate 15.67 g)-(mass of funnel 15.48 g)= (mass of CaCO3 precipitate 0.19 g) 0.19 g / .200 g = 95% yield 0.19 g x (1000 mg / (1 g x 20. mL) x (1000mL / 1 L) x (1/100) = 95 mg/L Moderately
In the Chemistry of Natural Waters Lab we were to collect a sample of water, ranging from a fountain, stream, bottle, or tap water. After we collected the samples we all did many tests to see what the hardness was for each one. Water hardness is determined by the amount of Calcium and Magnesium in the water.(2) Water that has more Calcium or Magnesium is considered to be harder than water with less of those two elements. When you use soap and detergent, this is where you see water hardness coming into play in everyday life when you are washing things.
If solid CaCO3 is combined with an aqueous solution of HNO3, Ca(NO3)2 as well as CO2 and H2O will form. The chemical equation for this reaction is CaCO3 (s) + 2 HNO3 (aq) → Ca(NO3)2 (aq) + CO2 (g) + H2O (l). To theoretically make one gram of Ca(NO3)2, 0.61 grams of CaCO3 need to be added with 0.768 grams of HNO3. Adding this two compounds will release CO2 gas into the air and will also from H2O to our compound. To get rid of the water and crystalize our compound, heat the beaker with the solution on a heating plate to evaporate the H2O. After letting the compound cool down, scape it onto a piece of paper and measure it’s mass.
The actual yield was found after massing the dried precipitate. The experimental amount was 0.046g of CoCO3 and 0.154g. By using the actual and theoretical yields the results for percent yield were 38.3% CoCO3 and 83.7% Ni3(PO4)2.
The mixture was then transferred to a clean centrifuge tube via pipet, carefully not wetting the upper walls of the tube. Zinc granules were then added and the tube was immediately plugged with cotton 1/3 of the way into the tube. The tube was then warmed in a hot water bath for about 5 minutes, the folded red litmus paper was inserted at the top of the tube with a wet crease. After a few minutes, nitrate is indicated on the wet crease of the litmus paper, turning it blue. For the Carbonate test, 25 mg of carbonate sample was added to a centrifuge tube and 3 drops of 6 M H2SO4 was added. A disposable pipet was used to transfer a drop of Ba(OH)2, that hung directly from the pipet over the carbonate solution, and the observations of the drop were recorded.
What Is the Percent by Mass of NaHCO3 in Alka-Seltzer Tablets? When it comes to understanding how starting material and product effect each other, it has been inevitably thought that the amount of starting material has always included a limiting and excess reactant that conclusively determines the product amount. The Lab Manual stated in applicable cases, such as buying amounts of starting material to form a certain product, could change a reaction, or have economic effects of wasting unnecessary amounts of material, therefore, unnecessary amounts of money.1 For instance, determining the amount of active ingredients in the fizz reaction of an Alka-Seltzer tablet is a great example to understand how much reactant is needed to cause the relief (determined by the product) according to the Lab Manual.1 According to researcher Dr. Catherine Chen, sodium bicarbonate is used for the acid-base netrualization.2 The Lab Manual presented the following reaction in which the active ingredient in Alka-Seltzer tablets sodium bicarbonate (NaHCO3) reacted with
Subsequently, HCl was added, drop-wise, to the labeled NaHCO3 extract. Once the solution had a pH of 2, additional HCl was not needed: 3-chlorobenzoic acid was precipitated. An ice-water bath beaker (250 mL) was made to cool the acidified solution. Eventually, a Buchner filtration apparatus was assembled with a pre-weighed filter paper; not to mention, wetted in the apparatus. Then the apparatus was attached to a water aspirator and the water valve was opened.
The purpose of this experiment is to familiarize oneself with the general procedures determining a partition coefficient at the microscale level and learn in weighing milligram quantities of materials on an electronic balance, the use of automatic pipets, the use of transfer pipet, and the use of a vortex mixer. Also, to familiarize oneself with extraction
Molarity × Volume = (0.0500 moles ×25.35 mL×1 liter)/(Litres×1000mL) = 0.00127 moles Theoretical yield grams = Moles of product × molecular weight of CaCO3 = 0.00127 moles × 100.089 g/moles = 0.127g Percent yield = (actual yeild (g))/(theoretical yeild(g))×100 = (0.0812g )/0.127×100 = 63.9 %
The amount if precipitate in each reaction will be measured against the volume ratio, then, the empirical formula can be found. The expected formula is Cu3(PO4)2 when predicted using the charges of ions, which would be at a 1 :1 ratio. Methods: First, seven small test tubes that are labeled in a test tube rack were obtained. Next, with two puppets ready, one pipet was filled with 0.1 M cooper (II) chloride and the other with 0.1 M sodium phosphate. Then, the appropriate number of drops of both solutions were added into the labeled test tubes.
1. Limewater Test: As we exhaled CO2 in the limewater solution, the CO2 reacted with Ca(OH)2 and changed the clear colorless limewater solution to precipitated white solution. The precipitation was caused due to the calcium in the limewater solution. It took us 5 attempts to turn the clear colorless limewater solution to a milky white solution. 2.
In this Separation of Mixtures lab, the substances, carbon, copper chloride, and water were separated from each other from a mixture. The hypothesis for this lab was “If the separation technique, boiling, is used to separate copper chloride from water, then 95% of the copper chloride will be recovered because copper chloride, which is soluble in water, won 't evaporate with the water.” The hypothesis was not supported by this lab. Although the lab confirmed that filtering and evaporating were the correct means of separation to use on carbon, water, and copper chloride, the overall result was not
To 1 mL of Barium chloride of another test tube, several drops of 3 moles of ammonium carbonate was added. Information was recorded when changes occurred. After precipitate has settled, the excess liquid was carefully poured out. 1 mL of water was then added to a test tube. it was shaken and allowed to let precipitate to settle down.
→ CaCO3(s) + NaOH Sodium carbonate and calcium hydroxide yields calcium carbonate and sodium hydroxide. This equation also in the Zeman Lackner method shows what happens when both aqueous solutions of sodium carbonate is mixed with solid calcium carbonate. H2O(l) + CO2(g) +CaCO3(s)→ Ca(CO)2(aq) Water, carbon dioxide and calcium carbon dioxide yields calcium carbonic. This equation shows what happens if too much carbon dioxide gas is added, the solid calcium carbonate reacts with the liquid water to produce an aqueous solution of calcium
To find the percent yield, the theoretical yield was calculated by using the stoichiometric ratio of the reactants, and the experiment was performed to find the actual yield. When the CaCl2 and NaHCO3 were mixed together, there was fizzing and bubbling that eventually led to a milky, chalky, white color. With the fizzing and bubbling, it was inferred that gas was released. As a result, a solution of calcium carbonate product formed. As the solution passed through the filter, layers of solid, white, calcium carbon built on top of each other and a cloudy filtrate appeared. Clearly, the microcrystal calcium carbonate suspended onto the filter. Additionally, because some of the product was too minuscule, it passed through the filter and less product was made (which means that the percent yield should be lower than 100 percent).
Titrating three trials with a known molarity allowed the mass of Na2CO3 to be determined experimentally. The measurements for each trial was shown in Table 1. Soda ash was experimented without interference of its impurities by utilizing the titration method.1 Knowing the molarity of the HCl solution while titrating soda ash allowed the moles of Na2CO3 found in soda ash to be calculated by the recordings of the titrant volume used and the mole ratio relationship shown in (1). The mole ratio can be used and converted into solving for the mass of Na2CO3 in order to solve for the weight percentage found in the unknown sample. Three trials of titration were tested and recorded.