MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Given: 4 NO2(g) + O2(g) 2 N2O5(g) ΔH = kj find ΔH for N2O5(g) 2 NO2(g) + 1/2 O2(g). A) kj B) kj C) kj D) 55.1 kj 1) 2) How much heat is absorbed when g of C(s) reacts in the pressence of excess SO2(g) to produce CS2(l) and CO(g) according to the following chemical equation? 5 C(s) + 2 SO2(g) CS2(l) + 4 CO(g) ΔH = kj A) kj B) 1918 kj C) kj D) kj 2) 3) Find ΔH for the reaction C 3 H 8 (g) + 5 O 2 (g) 3 CO 2 (g) + 4 H 2 O(l). ΔH = kj for the reaction: C 3 H 8 (g) + 5 O 2 (g) 3 CO 2 (g) + 4 H 2 O(g), and the heat of vaporization of water is 44.0 kj/mol. {Note that H 2 O is a liquid in the first reaction and a gas in the second.} A) kj B) kj C) kj D) kj 3) 4) The specific heat of copper is J/(g C). If 34.2 g of copper, initially at 25.0 C, absorbs kj, what will be the final temperature of the copper? A) 27.8 C B) 25.4 C C) 356 C D) 381 C 4) 5) How much heat is absorbed/released when g of NH3(g) reacts in the presence of excess O 2 (g) to produce NO(g) and H2O(l) according to the following chemical equation? 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(l) ΔH = kj A) kj of heat are absorbed. B) 1372 kj of heat are absorbed. C) 1372 kj of heat are released. D) kj of heat are released. 5) 6) Use the given standard enthalpies of formation to calculate ΔH for the following reaction 3 Fe2O3(s) + CO(g) 2 Fe3O4(s) + CO2(g). 6) Species ΔH f, kj/mol Fe 2 O 3 (s) Fe 3 O 4 (s) CO (g) CO 2 (g) A) kj B) kj C) kj D) kj 1

2 7) Acetylene torches utilize the following reaction: 2 C2H2(g) + 5 O2(g) 4 CO2(g) + 2 H2O(g) Use the given standard enthalpies of formation to calculate ΔH for this reaction 7) Species ΔH f, kj/mol C 2 H 2 (g) CO 2 (g) H 2 O (g) A) kj B) kj C) kj D) kj 8) Ethyl alcohol is produced by the fermentation of glucose, C6H12O6. C6H12O6(l) 2 C2H5OH(l) + 2 CO2(g) ΔH = -82 kj Given that the enthalpy of formation is kj/mol for C2H5OH(l) and kj/mol for CO2(g), find the enthalpy of formation for C6H12O6. A) kj/mol B) -671 kj/mol C) -753 kj/mol D) kj/mol 8) 9) Given: S (s) + O 2 (g) SO 2 (g) ΔH = kj 2 SO 3 (g) 2 SO 2 (g) + O 2 (g) ΔH = kj Find ΔH for : 2 S(s) + 3 O2(g) 2 SO3(g) A) kj B) kj C) kj D) kj 9) 10) If the number of moles of gas is doubled at constant temperature and volume, the pressure of the gas A) is halved. B) remains the same. C) is quadrupled. D) is doubled. 10) 11) Which equation represents the reaction whose ΔH, represents the standard enthalpy of formation of CHCl3(l) at 25 C? (i.e., for which is ΔH = ΔH f of CHCl 3 ) A) 2 C(s) + H2(g) + 3 Cl2(g) 2 CHCl3(l) B) C(s) + H(g) + 3 Cl(g) CHCl3(l) C) CHCl3(l) C(s) + H(g) + 3 Cl(g) D) C(s) + 1/2 H2(g) + 3/2 Cl2(g) CHCl3(l) 11) 12) Coal gasification can be represented by the equation: 2 C(s) + 2 H2O(g) CH4(g) + CO2(g) ΔH =? Use the following information to find ΔH for the reaction above. CO(g) + H2(g) C(s) + H2O(g) ΔH = -131 kj CO(g) + H2O(g) CO2(g) + H2(g) CO(g) + 3 H2(g) CH4(g) + H2O(g) ΔH = -41 kj ΔH = -206 kj A) 116 kj B) 15 kj C) -372 kj D) -116 kj 12) 2

3 13) An empty aerosol can at 25 C still contains gas at 1.00 atmosphere pressure. If an empty can is thrown into a 475 C fire, what is the final pressure in the heated can? A) atm B) 19.0 atm C) atm D) 2.51 atm 13) 14) A basketball is inflated to a pressure of 1.50 atm in a 20.0 C garage. What is the pressure of the basketball outside where the temperature is C? A) 1.37 atm B) 1.64 atm C) 1.42 atm D) 1.58 atm 14) 15) How many molecules of N2 are in a ml container at 780 mm Hg and 135 C? A) B) C) D) ) 16) What is the Celsius temperature of g of chlorine gas in a 40.0-L container at 800 mm Hg? A) 364 C B) 182 C C) -91 C D) 91 C 16) 17) A 75.0 L steel tank at 20.0 C contains acetylene gas, C2H2, at a pressure of 1.39 atm. Assuming ideal behavior, how many grams of acetylene are in the tank? A) 113 g B) 1650 g C) 4.33 g D) 6.01 g 17) In the diagram below, nitrogen molecules are represented by unshaded spheres, oxygen molecules by gray spheres, and chlorine molecules by black spheres. 18) If the total pressure in the container is 900 mm Hg, what is the partial pressure of nitrogen? A) 270 mm Hg B) 450 mm Hg C) 90 mm Hg D) 180 mm Hg 18) 19) A 1.00 L flask contains nitrogen gas at 25 C and 1.00 atm pressure. What is the final pressure in the flask if an additional 2.00 g of N2 gas is added to the flask and the flask cooled to -55 C? A) 2.01 atm B) 2.56 atm C) 1.28 atm D) 3.29 atm 19) 20) How many grams of O2 gas are there in a 5.00-L cylinder at mm Hg and 23 C? A) g B) 446 g C) 17.3 g D) 34.7 g 20) 21) An unknown gas effuses 1.73 times faster than krypton. What is the molar mass of the gas? A) 110 g/mol B) 251 g/mol C) 48.4 g/mol D) 28.0 g/mol 21) 22) Which of the following gases has the highest average speed at 400K? A) N2O4 B) SF6 C) CO2 D) UF6 22) 3

4 23) A kg sample of nitroglycerine, C3H5N3O9, explodes and releases gases with a temperature of 1985 C at atm. What is the volume of gas produced? 4 C3H5N3O9(l) 12 CO2(g) + 10 H2O(g) + 6 N2(g) + O2(g) A) 5203 L B) L C) 5919 L D) 3878 L 23) 24) When 15.0 g of zinc metal reacts with excess HCl, how many liters of H2 gas are produced at STP? A) L B) 5.14 L C) L D) 10.3 L 24) 25) Which of the following compounds exhibits only dispersion and dipole-dipole intermolecular interactions? A) HBr B) CO2 C) H2O D) N2 25) Use the diagram below to answer the following questions. 26) The solid and liquid phases can exist in equilibrium along line A) AC. B) BD. C) CD. D) CB. 26) 27) The temperature and pressure at which all three phases can coexist in equilibrium is A) 1.0 atm and 140 C. B) 1.25 atm and 300 C. C) 0.25 atm and 110 C. D) 0.45 atm and 130 C. 27) 4

5 Answer Key Testname: UNTITLED1 1) D 2) C 3) D 4) D 5) A 6) A 7) C 8) A 9) D 10) D 11) D 12) B 13) D 14) A 15) C 16) D 17) A 18) D 19) A 20) D 21) D 22) C 23) C 24) B 25) A 26) D 27) D 5