KEEP THIS SECTION!!!!!!!!!

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1 KEEP THIS SECTION!!!!!!!!! CHEMISTRY 0 Hour Exam I (Multiple Choice Section) September 7, 018 Dr. D. DeCoste Name Signature T.A. This exam contains 0 questions on 4 numbered pages. Check now to make sure you have a complete exam. Determine the best answer to these questions and enter these on the special answer sheet. Also, circle your responses in this exam booklet. Each multiple choice question is worth 3 points (total of 60 points). The free response section is worth a total of 60 points. Useful Information: Always assume ideal behavior for gases (unless explicitly told otherwise). PV = nrt R = Latm/molK = J/Kmol K = C + 73 NA = 6.0 x 10 3 υrms = 3RT M λ = 1 ( N / V )( πd ) ZA = A V N RT πm Z = 4 V N d πrt M x = - b ± b - 4ac a Solubility Rules: 1. Most nitrate salts are soluble.. Most salts of sodium, potassium, and ammonium cations are soluble. 3. Most chloride salts are soluble. Exceptions: silver, lead(ii), and mercury(i) chloride. 4. Most sulfate salts are soluble. Exceptions: calcium, barium, and lead (II) sulfate. 5. Most hydroxide salts can be considered insoluble. Soluble ones: sodium, potassium, and calcium hydroxide. 6. Consider sulfide, carbonate, and phosphate salts to be insoluble.

2 CHEMISTRY 0 Fall 018 Hour Exam I (Multiple Choice Section) Page No Determine the molar mass of aluminum sulfate in g/mol. a) b) c) d) e) 34.17, 3. A compound has a molar mass of g/mol and consists of carbon, hydrogen, and another element. This compound is % carbon and % hydrogen by mass.. Determine the identity of the other element. a) oxygen (O) b) sulfur (S) c) bromine (Br) d) iridium (Ir) e) At least two of the above elements (a-d) are possible given the data. 3. Determine the number of atoms in the empirical formula of the compound. a) 18 b) 3 c) 9 d) 51 e) At least two of the above numbers (a-d) are possible given the data. 4. Consider reactants, A and B. The molar mass of A is less than the molar mass of B. You add equal masses of A and B together and let them react. Which of the following statements must be true? a) If the coefficient for B is greater than the coefficient of A in the balanced equation, then reactant B must be limiting. b) If the coefficient for B is greater than the coefficient of A in the balanced equation, then reactant A must be limiting. c) If the coefficient for A is greater than the coefficient of B in the balanced equation, then reactant B must be limiting. d) If the coefficient for A is greater than the coefficient of B in the balanced equation, then reactant A must be limiting. e) None of the above choices (a-d) must be true. 5. Methane (CH4) reacts with oxygen gas to produce carbon dioxide and water. If equal masses of methane and oxygen are reacted to completion to produce 36.0 g of water, determine the mass of left-over reactant. a) 16.0 g b) 3.0 g c) 48.0 g d) 64.0 g e) More information is needed to answer this question.

3 CHEMISTRY 0 Fall 018 Hour Exam I (Multiple Choice Section) Page No. 6. Consider mixing 00.0 ml of 1.00M calcium nitrate with ml of 1.00M sodium carbonate to produce a solid. Determine the total concentration of ions in the solution after the precipitation is complete. a) 0.667M b) 1.00M c) 1.33M d) 1.67M e).33m 7. What mass of solid potassium carbonate is required to prepare 50.0 ml of a 0.10 M potassium carbonate solution? a).97 g b) 3.45 g c) 4.15 g d) 4.63 g e) 5.3 g 8. The gate-way reaction for budding chemists is the one between baking soda (sodium bicarbonate) and vinegar (an aqueous solution of acetic acid, HCH3O with a concentration of 0.841M) to produce sodium acetate, carbon dioxide gas, and water. NaHCO3(s) + HCH3O(aq) NaCH3O(aq) + CO(g) + HO(l) If we wish to react 0.0 g of baking soda, what is the minimum volume of vinegar required for a complete reaction? a) 84.1 ml b) 84 ml c) 44 ml d) 974 ml e) 7.00 L 9. A.5 g sample of scandium (Sc) metal is reacted with excess hydrochloric acid to produce.41 L of hydrogen gas at 100 C and atm. Determine the formula of the scandium chloride produced in the reaction. a) ScCl3 b) ScCl3 c) ScCl4 d) ScCl e) ScCl 10, 11. Consider heating a gas such that the final temperature is double the initial temperature (both measured in Kelvin). 10. Determine the value of eeeeeeeeeeeeeeee rrrrrrrr aaaa TT iiiiiiiiiiiiii eeeeeeeeeeeeeeee rrrrrrrr aaaa TT ffffffffff a) 0.50 b) 0.71 c) 1.0 d) 1.4 e) Determine the value of aaaaaaaaaaaaaa kkkkkkkkkkkkkk eeeeeeeeeeee aaaa TT iiiiiiiiiiiiii aaaaaaaaaaaaaa kkkkkkkkkkkkkk eeeeeeeeeeee aaaa TT ffffffffff a) 0.50 b) 0.71 c) 1.0 d) 1.4 e) You have equal masses of helium (He) and neon (Ne) gases in a steel rigid container. Determine the ratio of the frequency of collisions with the walls of the container for helium compared to neon. That is: [ZA of He] : [ZA of Ne]. a) 5.4 b) 11.3 c).5 d) 1.00 e)

4 CHEMISTRY 0 Fall 018 Hour Exam I (Multiple Choice Section) Page No You are holding two balloons at the same pressure and temperature: a 1.0 L argon (Ar) balloon and a.0 L neon (Ne) balloon. You decide to heat one of the balloons so that the gases in the balloons have the same density. What is the ratio of TAr/TNe (both temperatures in Kelvin) so that the gases in the balloons have the same density? a) 0.50 b) 1.0 c) 1.4 d).0 e) Indicate which of the graphs below best represents each plot described in questions 14, 15, and 16. Note: the graphs may be used once, more than once, or not at all. a) b) c) d) e) 14. Mean free path (λ) (y) vs. P (x) for an ideal gas in a rigid sealed container at constant temperature. 15. Volume (y) vs. T ( C) (x) for 1.0 mole of an ideal gas at constant pressure. 16. Volume (y) vs. molar mass (x) for g samples of a series of ideal gases in balloons at equal pressures and temperatures. 17. Consider gases A, B, C, and D in a container at equilibrium according to the generic equation: aa(g) + bb(g) cc(g) + dd(g) How many of the following statements are true? I. For a reaction in which Kp = K, adding a gaseous reactant will result in the equilibrium position being shifted to the right. II. For a reaction in which Kp K, adding a gaseous reactant will result in equilibrium position being shifted to the right. III. The addition of an ideal, inert gas at constant temperature cannot result in a change in the value of K or Kp; this is true if the reaction is in a rigid steel tank or a container fitted with a piston. IV. Changing the volume of the container may or may not result in a shift in equilibrium position. V. A change in total pressure in the container will always result in a shift in the equilibrium position. a) 1 b) c) 3 d) 4 e) 5

5 CHEMISTRY 0 Fall 018 Hour Exam I (Multiple Choice Section) Page No We have used solubility rules and labeled salts as soluble or insoluble, but it is not quite that simple. All salts are soluble to some extent (and no salt is infinitely soluble). For example, we call silver chromate insoluble, but this is because very little of it dissolves in water. If we placed g of AgCrO4(s) in L of room temperature water, let as much of it dissolve as possible, isolated the remaining solid and dried it, we would find that g of solid did not dissolve. Given these data, determine the value of the equilibrium constant at room temperature for the process of silver chromate dissolving: AgCrO4(s) Ag + (aq) + CrO4 (aq) a). x 10 1 b) 9.0 x 10 1 c) 3.1 x 10 9 d) 3.4 x 10 8 e) 3.3 x The gases N (partial pressure = 3.00 atm) and H (partial pressure = 4.00 atm) are placed in a steel rigid container. They react to equilibrium at constant temperature according to the following equation, for which Kp =.00: N(g) +3H(g) NH3(g) Determine the total pressure in the container after equilibrium is reached. a).00 atm b) 4.33 atm c) 5.00 atm d) 7.00 atm e) 14.0 atm 0. The gases NH3 (partial pressure = 5.0 atm) and O (partial pressure = 5.0 atm) are placed in a steel rigid container. They react to equilibrium at constant temperature according to the following equation, for which Kp = 1.0 x : 4NH3(g) + 5O(g) 4NO(g) + 6HO(g) Determine the equilibrium pressure of O(g). a) 7.6 x 10 5 atm b) atm c) atm d) 0.1 atm e) 1.9 atm

CHEMISTRY 202 Practice Hour Exam I. Dr. D. DeCoste T.A.

CHEMISTRY 202 Practice Hour Exam I Fall 2016 Dr. D. DeCoste Name Signature T.A. This exam contains 23 questions on 9 numbered pages. Check now to make sure you have a complete exam. You have two hours