Problem Sets 1 2 Chapters 11 5 PROBLEM SET 1 1 A 12 0 L sample of a gas at a constant pressure of 608 mm Hg was heated from 40 0oC to 60 0oC What volume does the gas now occupy a 18 L b 8 0 L c 12 8 L d 15 0 L e 11 3 L 2 A sample of chlorine gas at a pressure of 420 mm Hg and in a volume of 3 50 L was heated from 18 0oC to 45 0oC after being transferred to a container of volume 2 35 L The pressure in this new container should be about a 110 mm Hg b 680 mm Hg c 260 mm Hg d 280 mm Hg e 1560 mm Hg 3 For an ideal gas which pairs of variables are directly proportional to each other if all other factors remain constant The variables are 1 P T 2 P V 3 V T 4 n V a 1 and 2 only b 3 and 4 only c 1 and 3 only d 2 only e 1 3 and 4 only 4 Calculate the density of sulfur trioxide gas at 35 0oC and 715 torr pressure a 26 1 g L b 0 336 g L c 0 0382 g L d 2 98 g L e 2262 g L 5 Exactly 5 02 grams of an unknown gas was sealed in a 3 0 L flask at 37 0oC and a pressure of 1 25 atm Which one of the following is most likely to be the unknown a H2O b HBr c HCN d H2S e C2H2 6 A mixture of three gases has a total pressure of 1380 mm Hg at 25 oC If the mixture contained 56 grams CO2 3 04 mol CO and 9 03 X 1023 atoms of argon the partial pressure of argon would be about a 0 258 atm b 300 mm Hg c 360 mm Hg d 5300 mm Hg e 8000 mm Hg 7 Which statement below a d is incorrect Choose answer e if all are correct a When a gas is at STP the pressure of the gas is at 1 00 atm b When a gas is at STP the temperature of the gas is 25oC c At STP the molar volume of a gas is 22 4 L d At STP the molar volume of all gases are the same e All the statements above are correct see above 8 Choose the correct statement about the postulates of kinetic theory of gases a A sample of a gas consists of a small number of large particles close together b The movement of gas molecules is predictable not random c When gas molecules collide they permanently deform and lose energy d Gas molecules move very slowly e Forces between gas molecules attractive or repulsive are negligible 9 Which one of the following statements about gas particles is true a As the kinetic energy of a particle is halved its velocity is also halved b As the velocity of a particle is doubled the kinetic energy decreases by a factor of four c All particles having the same kinetic energy have the same mass d All particles at the same temperature have the same kinetic energy e All particles moving with the same velocity have the same kinetic energy 10 Which molecule below has the greatest average velocity at 100oC a He b Cl2 c Xe d O2 e NO2 PROBLEM SET 2 1 A cup of tea containing 400 0 g of liquid at 20 0oC was heated If 58 5 kJ of heat was absorbed by the tea what would the final temperature be Assume that the specific heat of the tea is the same as that of water 4 18 J g 1 K 1 a 55 0 oC b 28 6 oC c 35 0 oC d 48 6 oC e 15 oC 2 An insulated beaker contains 250 0 grams of water at 25oC Exactly 41 6 g of a metal at 100 0oC was dropped in the beaker The final temperature of the water was 26 4oC Assuming that no heat is lost in any other way calculate the specific heat of the metal a 0 159 J g 1 K 1 b 0 478 J g 1 K 1 c 0 0503 J g 1 K 1 d 2 09 J g 1 K 1 3 Which thermochemical equation and data does not agree with the other two written a 2 NO g O2 g 2 NO2 g H 169 8 kJ b NO g O2 g NO2 g H 56 6 kJ c 4 NO2 g 4 NO g 2 O2 g H 226 4 kJ d all three equations are in thermochemical agreement 4 For the reaction Al s 3 HCl aq AlCl3 s H2 g it was observed that when 4 00 g of aluminum reacted with excess HCl exactly 30 0 kJ of heat were released The Ho for this reaction is a 91 3 kJ b 120 kJ c 202 kJ d 7 50 kJ 5 The four statements below are used for applications of Hess s law One of the statements is erroneous Choose that statement a The value of Ho for any reaction that can be written in steps is the sum of the values of Ho for each of the individual steps b When an equation is reversed written in the opposite direction the sign of Ho must also be reversed becomes or becomes c Formulas cancelled from both side of an equation must be for substances in identical physical states d The value of Ho is independent of the stoichiometry so that if we change the equation Ho does not change 6 Calculate the value of Ho for the reaction 2 CH4 g C2H6 g H2 g given the following thermochemical equations C2H2 g H2 g C2H4 g Ho 175 1 kJ C2H6 g C2H4 g H2 g Ho 136 4 kJ C2H2 g 3 H2 g 2 CH4 g Ho 376 8 kJ a 65 3 kJ b 338 1 kJ c 415 5 kJ d 688 3 kJ 7 A piece of metal with a mass of 5 50 grams changed in temperature from 25 0 to 55 0oC when 21 3 joules was absorbed The specific heat of the metal is a 0 256 b 0 129 c 3 91 d 7 75 e 0 710 J g 1 oC 1 8 Consider the formation of sulfur trioxide according to the reaction 2 SO2 g O2 g 2 SO3 g Ho 198 kJ What is the value of Ho for SO3 g SO2 g O2 g a 99 kJ b 396 kJ c 396 kJ d 99 kJ e some other value 9 Consider the formation of sulfur trioxide according to the reaction 2 SO2 g O2 g 2 SO3 g Ho 198 kJ How much heat is evolved in the formation of 750 grams of SO3 a 10 6 kJ b 928 kJ c 1 86 X 103 kJ …