PRACTICE MINI EXAM 2 The exam will cover material from the chapter on Gases homework worksheets and any other topic covered during class and discussion The questions in this practice exam are of similar difficulty to those in the actual exam however the questions will not be the same Multiple choice I 1 Which of the following gases effuses most rapidly PRACTICE EXAM 1 A nitrogen B oxygen C hydrogen chloride D ammonia E carbon monoxide 2 Determine the molar mass of Freon 11 gas if a sample weighing 0 597 g occupies 100 cm3 at 95 C and 1 000 mmHg R 0 08206 L atm K mol 1 atm 760 mmHg A 0 19 g mol B 35 3 g mol C 70 9 g mol D 137 g mol E 384 g mol 3 Which conditions can cause nonideal gas behavior by 1 decreasing the space between gas particles or 2 by slowing gas particles so that interactions are significant A 1 high pressure 2 high temperature B 1 high pressure 2 low temperature C 1 low pressure 2 high temperature D 1 low pressure 2 low temperature E none of the above 4 A 3 76 g sample of a noble gas is stored in a 2 00 L vessel at 874 torr and 25 C What is the noble gas R 0 0821 L atm mol K A He B Ne 5 How many liters of O2 g are needed to react completely with 56 0 L of CH4 g at STP to E not enough information C Ar D Kr produce CO2 g and H2O g Given CH4 g 2O2 g CO2 g H2O g A 28 0 L B 56 0 L 6 The air pressure in a volleyball is 75 psi What is this pressure in torr 1 atm 14 7 psi E none of the above C 84 0 L D 112 L B 562 torr C 3900 torr D 7600 torr E 75000 torr 7 What are the conditions of STP 101 325 Pa 760 torr A 520 torr A 0 K and 1 atm B 273 15 K and 760 torr C 0 C and 760 atm D 273 15 C and 760 torr E 0 C and 1 torr 8 Divers often inflate heavy duty balloons attached to salvage items on the sea floor If a what is the volume of the balloon is filled to a volume of at a pressure of B 1 20 L C 0 833 L D 5 50 L balloon when it reaches the surface A 7 50 L E none of the above True False II 9 For all gas calculations the temperature must be in kelvins 10 One mole of F2 gas at STP would take up twice the volume of one mole of Ar gas at STP 11 Aerosol spray cans contain gas trapped in a fixed volume and cans of this type can explode if heated to high temperature This illustrates that pressure and temperature are directly proportional Short answer III 12 10 points In order to avoid a painful condition known as the bends deep sea divers breathe a mixture of helium and oxygen called heliox What percent by volume of this mixture must be oxygen in order to keep the partial pressure of oxygen to 0 20 atm the same as it is in sea level air The total pressure at the diving depth is 5 2 atm 13 25 points A piece of sodium metal reacts completely with water as follows 2 Na s 2H2O l 2NaOH aq H2 g The hydrogen gas generated is collected over water at 25 0 C The volume of the gas is 246 mL measured at 1 00 atm pressure How many grams of Na were used in the reaction The vapor pressure of water at 25 C is 0 0313 atm 14 10 points A gas evolved during the fermentation of glucose to make wine has a volume of 0 67 L at 22 5 C and 1 00 atm pressure What was the volume of the gas at its fermentation temperature 36 5 C H H H PV nRT Ptotal iPi 3 1 2 2 1 Equations and Data Sheet 2 2 2 1 1 1 1 2 1 atm 101325 Pa 760 mmHg 760 Torr 14 7 psi K C 273 15 Pressure units 1 bar 1 X 105 Pa R units R 8 31 J mol K 8 31 m3 Pa mol K 0 08206 L atm mol K qp H q m s T q C T 1 D 2 D Answer Key Practice Exam 1 3 B 4 C 5 D 6 C 7 B 8 A 9 T 10 F 11 T 12 3 85 13 0 448g 14 70 L