AP Chemistry Test (Chapter 3) Multiple Choice and FIB (40%)

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1 AP Chemistry Test (Chapter 3) Class Set Multiple Choice and FIB (40%) 1) A chemistry student is filtering and drying a precipitate that formed from two solutions reacting. Which one is most likely about the % yield for this experiment? A) Improper filtering would decrease the % yield and insufficient drying would increase the % yield. B) Improper filtering would increase the % yield and insufficient drying would decrease the % yield. C) Improper filtering would decrease the % yield and insufficient drying would decrease the % yield. D) Improper filtering would increase the % yield and insufficient drying would increase the % yield. 2) Which one best describes a dilute, unsaturated solution? A) Low M due to a small mass of solvent in the solution B) High M due to a large mass of solute in the solution C) Low M due to a small mass of solute in the solution D) High M due to a small mass of solute in the solution E) Low M due to a large mass of solute in the solution 3) What coefficients balance this reaction? C 6 H C 2 + H 2 A) 1, 8, 6, 7 B) 2, 17, 12, 14 C) 1, 9, 6, 14 D) 2, 19, 12, 14 4) What is the name of Al( 3 ) 3 9 H 2? A) Aluminum trinitrate nonahydrate B) Aluminum nitrogen oxide nonahydrate C) Aluminum nitrate hydrate D) Aluminum nitrate nonahydrate 5) Which one is a molecular formula? A) C 15 H 25 2 B) P 3 7 C) C 12 H 24 9 D) C 20 H 21 E) a 2 C 3 Please use the following information to answer questions mol A reacts with mol B in this reaction in a sealed flask: 2 A B 3 A 2 B 5 6) Which one is the limiting reagent? 7) How many mol A 2 B 5 are produced?

2 8) How many mol of the excess reagent are consumed during the reaction? 9) How many total mol are in the flask at the end of the reaction? 10) Please consider a homogeneous mixture of nitrogen and hydrogen in a 1:3 mole ratio and a sample of H 3 at room temperature. Which one is true? A) The mixture is physically combined and the ammonia is physically combined. B) The mixture and the ammonia are both liquids. C) The mixture and the ammonia have similar chemical properties. D) The mixture is odorless and the ammonia stinks. 11) Which one best explains what occurs over time when a piece of iron is exposed to air? A) Its mass increases due to the loss of iron when it forms iron oxide (rust). B) Its mass decreases due to the loss of iron when it forms iron oxide (rust). C) Its mass increases when it reacts with oxygen to form iron oxide (rust). D) Its mass decreases when it reacts with oxygen to form iron oxide (rust). 12) A solution is 1.23 M a 3 P 4 (aq). Which one best describes this solution? A) 1.23 mol a 3 P 4 = 1 L solution B) 1.23 g a 3 P 4 = 1 L solution C) 1.23 mol a 3 P 4 = 1 L H 2 D) 1.23 mol H 2 = 1 L a 3 P 4 13) Which one is the proper lab procedure for making 200 ml of M acl (aq)? A) Dissolve the acl (cr) in a beaker in a small volume of water, pour the solution into a 200-ml volumetric flask and then dilute the solution to the 200-ml mark with water. B) Dissolve the acl (cr) in a beaker in 200 ml of water and then pour the solution into a 200-ml volumetric flask. C) Dissolve the acl (cr) in a beaker in a small volume of water, pour the solution into a 200-ml volumetric flask and then add 200 ml of water. D) Place the acl (cr) in the volumetric flask and then add water to the 200-ml mark. 14) A solution is 11% acl by mass. Which one best describes this solution? A) 11 g acl = 100 g H 2 B) 11 g acl = 1 L solution C) 11 g H 2 = 100 g solution D) 11 g acl = 100 g solution E) 11 mol acl = 100 g solution 15) Please consider a mixture of sand, K 3 P 4, Cu, and plastic (low density). Which one is false about separating this mixture. A) nly physical changes occur. B) The plastic can be skimmed from the top of the mixture when water is added. C) The components of the filtrate K 3 P 4 and H 2. D) The K 3 P 4 can be recovered by evaporating the water added to the mixture. E) The Cu can be recovered by distillation of the solution.

3 16) What is the formula for cobalt (III) sulfate hexahydrate? A) Co 3 S 4 6 H 2 B) Co 2 (S 4 ) 3 6 H 2 C) Co(S 4 ) 3 6 H 2 D) CoS 4 7 H 2 17) Hydrogen reacts with oxygen to form dinitrogen pentoxide. Which one is true about the reaction illustrated here? Reactants A) 4 molecules of 2 5 are produced. B) 2 is the limiting reagent. C) 3 total molecules are in the flask at the end of the reaction. D) All chemical bonds are broken. E) 2 molecules of 2 remain in the flask at the end of the reaction. 18) How many atoms of hydrogen are in 5.00 g (H 4 ) 2 Cr 2 7? A) 1.49 X B) 9.55 X C) 6.07 X D) 1.19 X ) A solution is made by dissolving g ah into ml H 2. What is the mass % ah? A) 6.54% ah B) 14.3% ah C) 7.00% ah D) 15.3% ah 20) A certain diamond (only C) contains 3.51 X atoms of C. 1 carat has a mass of g. How many carats is this diamond? A) carats B) 103 carats C) 35.0 carats D) 1.40 carats

4 SI Revisited (10%) 1) (2 pts) Please give an example of something that would be measured in µg. 2) (2 pts) Which one is not a fundamental SI unit? A) Mass = kg B) Temperature = o C C) Amount of a substance = mol D) Luminous intensity = cd E) Time = s 3) (3 pts) How many dkm 2 are in nm 2? Please use dimensional analysis only and show all your work for any credit. 4) (3 pts) 2.54 cm = 1 inch. 12 inches = 1 foot. How many mm 3 are in a box that measures 5.00 ft by 2.00 ft by 4.00 ft? Please use dimensional analysis only and show all your work for any credit. Problems (60%) Please show all your work for any credit. 1) The following lab results were obtained when copper was strongly heated in the presence of excess oxygen. What is the empirical formula of the metallic oxide? Assume the copper did not react with atmospheric 2. Mass of empty crucible & cover Mass of crucible, cover & copper (before combustion) Mass of crucible, cover & copper (after combustion) g g g 2) A g sample of an organic compound composed entirely of carbon, hydrogen & oxygen was burned to produce g C 2 & g H 2. Assume complete combustion The molar mass of the compound is g. What is the molecular formula of this hydrocarbon? 3) An impure sample of solid sodium carbonate is allowed to react with a solution that is 1.39% HCl by mass. A g sample of the mixture containing the sodium carbonate requires g of the HCl solution to neutralize the sodium carbonate. What is the % a 2 C 3 in the original sample? a 2 C HCl 2 acl + C 2 + H 2 4) Stock phosphoric acid solution is 72.0% H 3 P 4 by mass & has a density of 1.68 g/ml. What is the molarity of this solution? 5) A reaction mixture contains g of PCl 3 & g of CrF 2. What mass of excess reagent remains after the reaction has gone to completion? 3 CrF PCl 3 2 PF CrCl 2

5 6) A metal M forms an oxide having the empirical formula M 5 8. This oxide contains % of the metal by mass. Calculate the atomic mass of the metal & then identify the metal. 7) A student uses ml of HCl solution to neutralize a sample of solid aluminum carbonate. The density of the HCl solution is 1.08 g/ml. The solution is 3.95% HCl by mass. The student collects and dries g AlCl 3. What is the % yield? 6 HCl + Al 2 (C 3 ) 3 2 AlCl H C 2 8) A solution is 16.52% a 3 P 4 by mass. The density of the solution is g/ml. What volume of solution contains g sodium phosphate? Please use dimensional analysis only. 9) A rock (ore) contains 71.25% azurite, Cu 3 (C 3 ) 2 (H) 2 by mass. What mass of copper could be extracted from g ore? Please use dimensional analysis only. 10) A hydrate contains % nickel (III) perchlorate & 9.168% water. What is the formula & name of this hydrate?

6 AP Chemistry Test (Chapter 3) ame Multiple Choice and FIB (40%) 1) 11) 2) 12) 3) 13) 4) 14) 5) 15) 6) 16) 7) 17) 8) 18) 9) 19) 10) 20) SI Revisited (10%) 1) 2) 3) 4) Problems (60%) Please show all your work for any credit.

AP Chemistry Test (Chapter 3) Multiple Choice and FIB (45%) 1) Which of these lab errors would cause a low % yield O 2?

AP Chemistry Test (Chapter 3) (Autumn) Multiple Choice and FIB (45%) 1) Which of these lab errors would cause a low % yield 2? 2 KCl 3 (s) 2 KCl (s) + 3 2 (g) I) Using a crucible that has soot stuck to