Chemistry



Name:________________________Hour:____Date:___________AP Chemistry: 3HWDirections: Complete the following problems.Find the formula weight and molar mass of:1A. tin(IV) sulfate 1B. aluminum bromite2A. Find the mass of each element present in a 0.5625 g sample of ammonium cyanide. 2B. Suppose that a biological molecule is 0.435% iron by mass and that each such molecule contains three iron atoms. Find the compound’s molar mass.3A. Cholesterol is 83.94% carbon, 11.92% hydrogen, and 4.15% oxygen by mass. Find cholesterol’s empirical formula. ANSWERS:1A. f.w. = 310.9 amu; mm = 310.9 g2A. 0.3580 g N, 0.1534 g C, 0.0511 g H3A. C27H46O1B. f.w. = 362.7 amu; mm = 362.7 g2B. 38,500 g3B. Codeine is 72.24% carbon, 7.02% hydrogen, 16.05% oxygen, and 4.68% nitrogen by mass. Find codeine’s empirical formula.4A. A sample of a compound is found to contain 23.03 g phosphorus, 5.22 g nitrogen, and 26.39 g chlorine. The compound’s molar mass is 441 g. Find its molecular formula.4B. Lactic acid is a ternary oxyacid that is 40.00% carbon and 6.67% hydrogen. If 0.377 moles of lactic acid have a mass of 33.93 g, find the molecular formula of lactic acid.Given the following laboratory data, find the formula of each hydrate.5A. mass of beaker = 57.84 gmass of beaker and contents before heating = 64.53 gmass of beaker and contents after heating = 61.48 gmolar mass of anhydrous salt = 85.9 gANSWERS:3B. C18H21O3N4A. P6N3Cl64B. C3H6O35A. MN . 4 H2O5B. mass of beaker = 74.22 gmass of beaker and contents before heating = 96.43 gmass of beaker and contents after heating = 86.28 gchemical name of anhydrous salt = barium hydroxide6A. What volume is occupied at STP by approximately one billion atoms of neon?6B. How many carbon atoms are in a 1.5-carat diamond? (1 carat = 0.200 g)7A. How many nitrogen atoms are in 18.8 g of barium nitride?7B. How many oxygen atoms are in 7.25 g of calcium nitrate?8A. When lighting a match on a matchbox, red phosphorus (P4) reacts with potassium chlorate to form potassium chloride and tetraphosphorus decoxide. If 0.113 g of potassium chlorate reacts with excess red phosphorus, what mass of tetraphosphorus decoxide will be produced?8B. Ammonium thiocyanate (NH4SCN) and barium hydroxide octahydrate (Ba(OH)2.8 H2O) react to produce barium thiocyanate, water, and ammonia (NH3). What mass of ammonium thiocyanate reacts completely with 24.8 g of barium hydroxide octahydrate?ANSWERS:6A. 4 x 10–14 L 7A. 5.15 x 1022 at.8A. 0.0785 g5B. Ba(OH)2 . 8 H2O6B. 1.5 x 1022 at. 7B. 1.60 x 1023 at. 8B. 12.0 g9A. The peroxide ion is O22–. Barium peroxide and nitric acid react to produce hydrogen peroxide and barium nitrate. What mass of hydrogen peroxide is produced when 1.46 g of barium peroxide react with 30.0 mL of nitric acid solution that contains 0.0754 g of the acid per mL?9B. In the gaseous reaction between ammonia, oxygen gas, and methane, hydrogen cyanide and water are produced. Ideally, what mass of each product is yielded if you start with 600. g of each reactant?10A. If 25.0 g of carbon monoxide react with 8.50 g of ammonia and 10.0 g of hydrogen to produce water and acetonitrile (CH3CN), what mass of each excess reactant is left over after the reaction is complete?ANSWERS:9A. 0.293 g9B. 338 g hydrogen cyanide;10A. 0.91 g ammonia; 675 g water 8.21 g hydrogen10B. Silver nitrate and cobalt(II) chloride react in solution to produce two products, one of which is a silver chloride precipitate. If 87.4 g of silver nitrate and 38.5 g of cobalt(II) chloride are put together in solution, what mass of excess reactant remains after the reaction is complete?11A. Bornite (Cu3FeS3) is an ore that, when reacted with oxygen, will yield iron(II) oxide, sulfur dioxide, and copper. If the process has a 75.5% yield, how many metric tons of copper are produced from the reaction between excess oxygen and 5.25 metric tons of bornite? (1 metric ton = 1000 kg)11B. In the reaction between red phosphorus (P4) and fluorine, phosphorus trifluoride is produced. If the percent yield is 82.6%, what mass of fluorine is needed to produce 152 g of phosphorus trifluoride?ANSWERS:10B. 5.1 g 11A. 2.20 metric tons11B. 119 g ................
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