Gas Law Review
 1 A sample of krypton gas with a volume of 6.25 L, a pressure of 102 kPa and a temperature of 20.0oC expanded to a new volume of 9.55 L and a pressure of 50 kPa.  What is its final temperature in oC? 2 A sample of Freon, a refrigerant gas, that has been banned, occupies a volume of 445 mL, at a pressure of 1.50 atm and a temperature of 25.0oC.  It is compressed into a volume of 225 mL with a pressure of 2.00 atm.  To what temperature did it have to change? 3 A steel cylinder containing nitrogen has a volume of 25.0 L at 24oC and a  pressure of 150 atm.   How many grams of nitrogen does this cylinder hold? 4 What is the density, in g/L, of each of the following gases at STP? a) CH4      b) O2       c) H2 5 At 100.2 kPa and 20.0oC, what is the density of argon in grams/litre? 6 Working on a vacuum line, a chemist isolated a gas in a weighing bulb with a volume of 255 mL, at a temperature of 25.0oC, and under a pressure of 1.3 kPa.  The gas weighed 12.1 mg.  What is the molecular mass of this gas? 7 In the Haber process of synthesizing ammonia: N2(g)  +  3 H2(g) ---->  2 NH3(g) How many litres of N2 are needed to react completely with 45.0 L of H2 if both gases are at STP? 8 In the first step of the Ostwald process for making nitric acid, ammonia reacts with oxygen at 650oC and 1 atm.  the following reaction occurs:        4 NH3(g)   +   5 O2(g)   ----->   4 NO(g)   +  6 H2O(g) How many litres of oxygen at 650oC and 1 atm are needed to react with 48 L of NH3 also at 650oC and 1 atm? 9 A common laboratory preparation of hydrogen  on a small scale uses the reaction of zinc with hydrochloric acid that produces zinc chloride and hydrogen a)  Write a balanced chemical equation b)  If 10.0 L of hydrogen at 101.3 kPa and 25.0 is wanted, how much zinc is needed in theory? c)  How many moles of HCl are needed if we use the condition from part b)? 10 One industrial synthesis of acetylene, a gas used as a raw material for making countless synthetic drugs, dyes, and plastics, is the addition of water to calcium carbide.                         CaC2(s)  +     2 H2O(l)  -------->  Ca(OH)2(aq)   +   C2H2(g) a)   In a small scale test to improve efficiency, 100 grams of CaC2 is converted into acetylene.  What is the theoretical yield of acetylene in moles and litres at SATP? b)   To make 1.0 X 106 L of acetylene at SATP by this method requires how much calcium carbide in kilograms? 11 A steel cylinder contains neon at a pressure of 101.325 kPa and a temperature of 25oC.  The cylinder survives a fire in which the temperature reaches 800oC.  What would be the internal pressure of the cylinder. (Expansion of the metal cylinder will increase the volume slightly but will be considered negligible.)  Express the result in atmospheres and MPa. 12 A sample of 248 mL of wet nitrogen gas was collected over water at a pressure of 98.13 kPa and a temperature of 21.0oC.  (The vapour pressure of water at 21oC is 2.49 kPa.)  The nitrogen was produced by the reaction of sulfamic acid, HNH2SO3, with 425 mL of a solution of sodium nitrite according to the following reaction.          NaNO2(aq)  +   HNH2SO3(aq)  ---->  N2(g)  +  NaHSO4(aq)  +  H2O(l) Calculate the molar concentration of the sodium nitrite solution. 13 Hydrogen peroxide, H2O2, is decomposed by potassium permanganate according to the following reaction:     5 H2O2  +   2 KMnO4  +  3 H2SO4  --->  5 O2  +  2 MnSO4  +  K2SO4  +  8 H2O What is the minimum number of millilitres of 0.125 M KMnO4 solution required to prepare 375 mL of dry O2 when the gas column is measured at 22oC and 98.39 kPa.  The gas is collected over water.  PH2O@22oC = 2.67 kPa 14 The density of a certain gas at 27oC and 98.66 kPa is 2.53 g/L.  Assuming that the gas behaves in an ideal manner, calculate its molecular mass. 15 A certain gas is found to have a density of 0.16 g/L at 25oC and 99.34 kPa. What is the molecular mass of the gas? 16 An explosion occurs as a result of a rapid chemical reaction attended by the formation of a large volume of gas.  The equation for the detonation of nitroglycerine is:        4  C3H5(NO3)3(l)  ------>   12 CO2(g)  + 10 H2O(l)  +  6 N2(g)  +  O2(g) 52 grams of nitroglycerine is packed into the inside of a hand grenade.  At the moment of explosion, the nitroglycerine reaches a temperature of 700oC.  If the volume of the inside of the hand grenade is 200 mL, what is the pressure in atmospheres just before the metal grenade case fractures into shrapnel?