Unit 5 Practice Problems

10) What volume (L) of NHygas at SIP is produced by the complete reaction of 75 g of H2O according to the following reaction? Mg3N2(9) 1 61120(1) - 3Mg(OHD)2 (a4) + 2NHa (g) A) 19 B) 28 C) 0.32. D) 9.31 1) 3.1 11) A sample of an unknown volatile liquid was injected into a Dumas flask (mflask - 27.0928 g, Vflask = 0.1040 .) and heated until no visible traces of the liquid could be found. The flask and its contents were then rapidly cooled and reweighed (mflask i vapor * 27.4593 g). The atmospheric pressure and temperature during the experiment were 0.976 atm and 180C, respectively. The unknown volatile liquid was Л) C6H14 B) C6H6 C) 07l16 D) C6F112 E) C71014 12) The densily of air al SIP is 1.285 g/L. Which of the following cannot be used to fill a balloon that will float in air at SIP? A) NH3 B) Ne C.) NO D) CH4 E) HI 13) A sample of He gas (3.0 t.) at 5,6 atm and 25°C was combined with 4.5 l. of Ne gas at 3,6 atm and 25 C at| constant temperalure in a 9.0 L flask. The total pressure in the flask was _ alm. Assume the initial pressure in the flask was 0.00 atm. 1) 3.7 B) 2.6 C) 9.2 1)) 1.0 E) 24 14) In a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is partial pressures of He and Ne are 1.50 and 2.00 atm, respectively. A) 0.357 B) 0.179 C) 0.238 12) 0.417 if the E, 0.583 15) Sodium hydride reacts with excess water lo produce aqueous sodium hydroxide and hydrogen gas: NaH (s) : 1120(1) → NaOH (aq) • 112 (g) A sample of Nalf weighing § will produce 982 ml. of gas at 28C and 765 toer, when the hydrogen is collected over water. The vapor pressure of water at this temperature is 28 torr. Л) 0.960| 13) 2.93 C) 0.0388 D); 0.925 E:) 925 16) S02 (5.0 g) and CO2 (5.0 g) were placed in a 750 ml. container at 50C. The partial pressure of CO2 in the container was A) 2.761 afm. 18) 0.192 C) 6.781 D) 4.02 7) 1.60| 17) The kinetic-molecular theory predicts that pressure rises as the temperature of a gas increases because A) the gas molecules collide less frequently with the wall B) the gas molecules collide more energetically with the wall C) the gas molecules collide more frequently with the wall D) the average kinetic energy of the gas molecules decreases 15) both the gas molecules collide more frequently with the walland the gas molecules collide more energetically with the wall Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The volume of a balloon is L at a depth of 50.2 meters if its volume on the surface of the water was 284 L. 9.1 meters of water equals one atmosphere. Assume constant temperature. A) .3.05 B) 1.70 C) 0.939 D) 1.06 E) 4.74 2) A sample of gas (24.2 g) initially al 4.00 alm was compressed from 8.00 L. to 2.00 1. at constant temperature. Aftes the compression, the gas pressure was atm. A) 1.00| 13) 4.00 C) 16.0| D) 2.00 2) 8.00 3) A balloon originally had a volume of 4.39 L at 45C and a pressure of 729 torr. The balloon must be cooled to *C to reduce its volume to 3.78 L (at constant pressure). A) 38 B) 546 C, 729 D)01 1) 2731 4) When an additional mol of gas is addled at constant temperature and volume lo a flask containing, 2.00 mol of gas at 25°C and 1.00 atm pressure, the pressure incrcases to 1.60 atm. A) 1.00 B) 1.20 (*) 0.800 D) 521 E) 3.20 5) A sample of a gas (1.50 mol) is contained in a 15.0 L cylinder. The temperature is increased from 100C to 150C. The ratio of final presume to initial pressure pi A) 1.00| B3) 0.667 C) 0882 D) 1.50 E) 1.13 6) A sample of a gas originally at 25 C and 1.00 atm pressure in a 25 L container is allowed to expand until the pressure is 0.85 atm and the temperature is 13C. The final volume of the gas is A) 2.1 B) 3.0 C)26| D) 28 L) 0.38 2) Which statement about ideal behavior of gases is false? A) Low pressures and high temperatures typically cause deviations from the ideal gas behavior. 13) At low densities all gases have similar properties. C) Gas ideality assumes that there are no inferactions between gas particles. D) Volume of 2.00 moles of oxygen gas, 02, is assumed to be the same as that of 2.00 moles of carbon dioxide gas, COz, as long as the temperature and pressure conditions are the same. 1) All particles in the ideal gas behave independently of each other. 8) The density of A) Nel -_ Is 0.900 g/L. at STP. B) CO C) N2 D) NOT 1) CH4 9) What volume (ml.) of sulfur dioxide can be produced by the complete reaction of 3.82 g of calcium sulfite with excess HCJ (aq), when the fina! SO2 pressure is 827 torr at 45C? A) 761 B) 378| C) 1.39 × 10-4 D; 0.106 18) 1.00 × 10-3 18) According to kinetic-molecular thcory, if the temperature of a gas is raised from 100C to 200°C, the average kinetic energy of the gas will A) increase by a faclor of 10) B) increase by a factor of 1.27 C) decrease by a factor of 100 D; decrease by hait F, double 19) A tank containing both FTl and 103r gases developed a Icak. The ratio of the rate of effusion of FH to the rate of effusion of HBr is_ A) 0.497 B) 16.3 C)0.247 D) 2.01 E) 4.04 20) A sample of Nagas (20 mmol) effused through a pinhole in 55s. It will lake of CHy to effuse under the same conditions. A) 5.5 B) 3.1 C) 7.3 1D) 4.2 _s for the same amount E) 9.6 21) The van der Waals equation for real gases recognizes that A) the molecular altractions between particles of gas decreases the pressure exerted by the gas B) gas particles have non-zero volumes and interact with each other C) molar volumes of gases of different types are different D) the non zero volumes of gas particles effectively decrease the amount of "empty space" belween them E) all of the above statements are true 22) Zine reacts with aqueous sulfuric acid to form hydrogen gas: Za (s) | 11250g (aq) - ZnSOg (aq) • H2 (g) In an experiment, 225 m L of wet 112 is collected over waler al 27°C and a barometric pressure of748 lorr. How many grams of Zn have been consumed? The vapor pressure of water at 27C is 26.74 torr. A) 431 B) 4.31 × 105 C) 0.567 D) 567 E) 4.79 × 100 23) The principal source of the difference in the noral boiling puint- of K1(97C; molecular mass 162 amu) and Bry (59C; molecular mass 160 amu) is A) hydrogen bonding 8) dipole-dipole inieractions C) london-dispersion forces D) both hydrogen-bonding and dipole-dipole interactions L) both dipole-dipole interactions and I ondon dispersion forces ESSAY. Write your answer in the space provided or on a separate sheet of paper. 24) Explain why, at room lemperature, iodine is a solid, bromine is a liquid, and chiorine is a gas. Answer Key Testame: PRACTICE FOR UNIT 5.TST MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) B 2) C 3) D 4 В 5) E 6) D 7) А 81 Л 9) A 10) F 31) A 12) C 131| 16)| 17) 1: 18) B 19)| D 20) D 210) 13 22) C 23) B ESSAY. Write your answer in the space provided or on a separate sheet of paper. keep the molecules close together. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. ESSAY. . Write your answer in the space provided or on a separate sheet of paper. 26) Normal hydrocarbons can align to contact each other over their entire lengths and branched hydrocarbons cannol. This causes the london-dispersion forces befeen normal hydrxarbons to be greater than those between branched hydrocarbons. MULTIPLE CHOICE. Choose the one aiternative that best completes the stalement or answers the question. 27 Л 281 A 29) A 301 C