question archive Find the precipitate reaction to determine the % purity of the CaBr2 in a very old and crusty bottle labeled "Calcium Bromide
Find the precipitate reaction to determine the % purity of the CaBr2 in a very old and crusty bottle labeled "Calcium Bromide
Subject:ChemistryPrice:6.86 Bought12
Find the precipitate reaction to determine the % purity of the CaBr2 in a very old and crusty bottle labeled "Calcium Bromide." You carefully measure out 20.000 grams of solid CaBr2 and add water until the total volume of the solution is 750.00 mL. You recently bought a guaranteed 1.0000 M solution of high quality Na3PO4. You measure out 200.00 mL of the 1.0000 M Na3PO4 and add 100.00mL of water to make a dilution. You are going to mix 50.00 mL of your CaBr2 solution with some of your diluted Na3PO4 and filter out the precipitate.
a)Calculate the molarity of the diluted Na3PO4 solution you made
b)In order to ensure that the reaction is limited by the 50.00 mL of the impure CaBr2 solution, calculate the minimum volume, in mL, of the diluted Na3PO4 solution must you use. To be extra, super sure, that the Na3PO4 is the excess reactant, you add double the minimum volume. What volume do you add?
c)What is the theoretical yield of the precipitate in grams? (The molar mass of Ca3(PO4)2 is 310.18 g/mol)
d)Pretend the only source of error is the impurity of the CaBr2. If 0.5320 grams of precipitate are obtained, what is the percent purity of the CaBr2?
Purchase A New Answer
Custom new solution created by our subject matter experts
GET A QUOTE
Answer Preview
(a) 0.6667 M Na3PO4
(b) 13.34 mL of Na3PO4
(c) 0.6897 g of precipitate
(d) 77.14%
Steps in calculation:
(i) Make a balance chemical reaction between CaBr2 and Na3PO4.
(ii) Calculate the moles of CaBr2 in 20.000g. Calculate it's molarity concentration in 750.0 mL (0.7500 L). You will use this concentration in later steps.
(iii) To calculate concentration of diluted Na3PO4, use dilution formula. The V2 will be 300.0-mL since you added 100.0-mL to 200-mL.
(iv) You can use stoichiometric calculation to determine the minimum volume of Na3PO4. Use the balance chemical reaction in step (i) to get the stoichiometric ratio of CaBr2 and Na3PO4. Double the calculated volume to make sure.
(v) To get the theoretical yield, use the concentration of CaBr2, because you wanted the reaction to be limited to CaBr2. Again, use the balance chemical reaction in step (i) to get the stoichiometric ratio of CaBr2 and Ca3(PO4)2.
(vi) To calculate purity of CaBr2, divide your actual yield with the theoretical yield in step (v).
Please see the attached file for the complete solution
