Gravimetric Analysis of Metal Carbonate
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Gravimetric Analysis of Metal CarbonateTamer El-Maghrabi, Lauren October 3, 2016Data:Mass beaker: 136.192 gMass beaker + alkali metal carbonate: 137.716 gMass alkali metal carbonate: 1.524 gMass of two filter papers: .577 gMass beaker, filter papers, SrCO3: 138.262 gMass SrCO3: 1.493 gColor of flame: YellowCalculations:Calculate the experimental percent of carbonate in the alkali metal carbonate.1.493g SrCO3 X (1 mol SrCO3 / 147.6g SrCO3) X (1 mol CO3 / 1 mol SrCO3) X 59.98g CO3 / 1 mol CO3 = .6067g CO3.6067g / 1.493g X 100 = 40.6 %Calculate the theoretical percent of carbonate in each alkali metal carbonate.Li2CO3: 6.94 X 2 = 13.8813.88 + 59.98 = 73.8659.981 / 73.86 X 100 = 81.21% Na2CO3: 22.99 X 2 = 45.98 45.98 + 59.98 = 105.96 59.98 / 105.96 X 100 = 56.61 % K2CO3: 39.10 X 2 = 78.20 78.20 + 59.98 = 138.18 59.98 / 138.18 = 43.41 % Rb2CO3: 85.47 X 2 = 170.94 170.94 + 59.98 = 230.92 59.98 / 230.92 X100 = 25.97%1 a)Show, by calculation, that the addition of 60 mL of .20 M SrCl2 is in excess and that the unknown alkali metal carbonate is the limiting reagent.
SrCl2:Moles = concentration X Volume60 mL / 1000 mL = .060 LMoles = (.20 mol/L) X (.060L)Moles = .012 molCo3 (aq): 1.524g mass of metal carbonate – .9037 g mass of sodium in the metal carbonate = .6203g CO3 .6203g CO3 X (1 mol CO3 / 59.98g CO3) = .01035 mol CO3 .012 moles Sr X (1 mol CO33 / 1 mol Sr ) = .012 mol CO3.01035 mol CO3 X ( 1 mol Sr / 1 mol CO3 ) = .01035 mol SrIt is assumed that strontium carbonate is insoluble. However, a very small amount of strontium carbonate is soluble in waterWhat is the solubility of strontium carbonate?Solubility product of SrCO3, Ksp = 5.60e-10Solubility product Ksp = [Sr+2][Co3-2]5.60e-10 = s2s = 2.37e-5 mol/LDiscussion:Calculate the experimental percent of carbonate in the alkali metal carbonate.By using the experimental mass for 1.493g SrCO3, I used stoichiometry to find the grams of carbonate. I then divided this mass by the original experimental mass and multiplied by 100 to get 40.6 %.Calculate the theoretical percent of carbonate in each alkali metal carbonate.I found the molecular weight of the alkali metals plus the carbonate. Using this, I divided this mass mass of carbonate by the total. As a result, I got the following for each alkali metal carbonate: