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18 Nov 2019
2.(20pts) (a) 16pts An element having the average atomic mass of 28.09 has three isotopes. Determine the missing quantities in the table below: Isotope Abundance (%) Mass of Isotope 27.97693 92.23 4.67 28.97649 Hint: Recall that the sum of the abundances must equal 100 %. (b) 4pts Draw a crude sketch of the mass spectrum corresponding to the information in the completed table 3.(33pts) Consider the reaction 3 Pb(NOs)2 + 2 NasPOPb,(PO)2+6 NaNO If 86.72 g of Pb(NOs)h are mixed with 22.80 g of Na,POs and the above reaction is occurs, answer the following questions (a) 11pts What is the limiting reagent? A guess is not sufficient: work must be shown. (b) 11 pts How many grams of NaNO, can be produced under the above conditions? (c) 11 pts If 34.63 g of NaNO, are obtained when the reaction is performed in the laboratory under the conditions stated in (a), what is the percent yield? Data: Molar Mass Pb(NO,) 331.21, Na PO-163.89, Pb,(PO4)2-881.51, NaNO 84.99 4(20pts) Pilocarpine is used in the treatment ofglaucoma, and it has the percent composition: %C 69077, %H 7.906 % , %N 14.651, % O 8.366. Compute the empirical formula of this compound. Bonus problem: (5pts No partial credit) Nitric Acid can be prepared from ammonia by the following steps: 4 NH+ 502 6H2O+4 NO 2 NO + 02 --..> 2 NO2 2 NO2 + HHNO,+HNO2 HNO> HNO+2 NO+HO If all steps take place consecutively, how many grams of NH, are needed to prepare 43.0 g of HNO,? Hint: Problem can be done in several ways. One method is to multiply the various equations by appropriate constants and then add the resulting equations to get a master equation that can be used to do the calculation.
2.(20pts) (a) 16pts An element having the average atomic mass of 28.09 has three isotopes. Determine the missing quantities in the table below: Isotope Abundance (%) Mass of Isotope 27.97693 92.23 4.67 28.97649 Hint: Recall that the sum of the abundances must equal 100 %. (b) 4pts Draw a crude sketch of the mass spectrum corresponding to the information in the completed table 3.(33pts) Consider the reaction 3 Pb(NOs)2 + 2 NasPOPb,(PO)2+6 NaNO If 86.72 g of Pb(NOs)h are mixed with 22.80 g of Na,POs and the above reaction is occurs, answer the following questions (a) 11pts What is the limiting reagent? A guess is not sufficient: work must be shown. (b) 11 pts How many grams of NaNO, can be produced under the above conditions? (c) 11 pts If 34.63 g of NaNO, are obtained when the reaction is performed in the laboratory under the conditions stated in (a), what is the percent yield? Data: Molar Mass Pb(NO,) 331.21, Na PO-163.89, Pb,(PO4)2-881.51, NaNO 84.99 4(20pts) Pilocarpine is used in the treatment ofglaucoma, and it has the percent composition: %C 69077, %H 7.906 % , %N 14.651, % O 8.366. Compute the empirical formula of this compound. Bonus problem: (5pts No partial credit) Nitric Acid can be prepared from ammonia by the following steps: 4 NH+ 502 6H2O+4 NO 2 NO + 02 --..> 2 NO2 2 NO2 + HHNO,+HNO2 HNO> HNO+2 NO+HO If all steps take place consecutively, how many grams of NH, are needed to prepare 43.0 g of HNO,? Hint: Problem can be done in several ways. One method is to multiply the various equations by appropriate constants and then add the resulting equations to get a master equation that can be used to do the calculation.
Irving HeathcoteLv2
28 Mar 2019