Exam 4
Gaseous chlorine is held in two separate containers at identical temperature and pressure. The volume of container 1 is 1.30L and it contains 6.70mol of the gas. The volume of the container 2 is 2.33L. How many moles of the gas are in container 2? a) 12.0 mol b) 20.3 mol c) 0.452 mol d) 3.74 mol e) none of these
a) 12.0 mol
It is possible to make a barometer using a liquid other than mercury. What would be the height (in meters) of a column of carbon tetrachloride at a pressure of 0.890atm, given that 0.890atm is equal to a 0.676m column of mercury and the densities of mercury and carbon tetrachloride are 13.5 g/cm^3 and 1.58 g/cm^3, respectively. a) 5.78 m b) 0.173 m c) 0.0792 m d) 1.07 m e) 0.936 m
a) 5.78 m
What volume of O2, measured at 24.0C and 0.620 atm, will be produced by the decomposition of 3.00g KClO3? Assume 100% yield 2KClO3 -> 2KCl + 3O2 a. 1.42 x 10^3 ml b. 9.47 x 10^2 ml c. 1.15 x 10^2 ml d. 6.31 x 10^2 ml e. none of these
a. 1.42 x 10^3 ml
A 3.74 gram sample of a certain diatomic gas occupies a volume of 3.48L at 1.00atm and a temperature of 45C. Identify the gas. a. H2 b. N2 c. Cl2 d. O2 e. F2
b. N2
Place the following gases in order of increasing average velocity at 300K: Ar, CH4, N2, and N2O a. Ar=CH4=N2=N2O b. N2O<Ar<N2<CH4 c. N2O<N2<CH4<Ar d. Ar<N2<N2O<CH4 e. CH4<N2<N2O<Ar
b. N2O<Ar<N2<CH4
Real gases deviate from ideal behavior for two reasons: (1) real gas molecules have intermolecular forces and (2) real gas molecules have a. pressures within the chemical bonds b. nonzero molecular volumes c. ionization energies d. molecular vibrations e. a distribution of molecular speeds
b. nonzero molecular volumes
At STP, as the molar mass of the molecules that make up a pure gas increases, the a. rms speed increases b. rms speed decreases c. rms remains constant d. rms increases to a maximum, then decreases e. none of the above
b. rms speed decreases
What volume of gaseous water, H2O, has the same moles of gas as 10.0L of xenon gas at the same temperature and pressure? a) 40.0 L b) 2.50 L c) 10.0 L d) 3.33 L e) 30.0 L
c) 10.0 L
Sodium azide decomposes rapidly to produce nitrogen gas 2NaN3 -> 2Na + 3N2 What mass of sodium azide will inflate a 60.0L airbag for a car to a pressure of 1.50atm at 32C? a. 2.40g b. 67.2g c. 156g d. 234g e. 351g
c. 156g
Aqueous hydrochloric acid reacts with magnesium to produce hydrogen gas according to the balanced equation below 2HCl + Mg -> MgCl2 + H2 If 250.0mL of 3.00M HCl is combined with 9.92g Mg, what volume of hydrogen gas can be produced? Assume the temperature and pressure of the gas are 25C and 0.988atm, respectively a. 4.60L b. 5.05L c. 928L d. 10.1L e.18.6L
c.9.28L
What is the pressure of a 59.6L gas sample containing 3.01 mol of gas at 44.9C? a) 1.41 x 10^2 mmHg b) 1.73 x 10^-3 mmHg c) 1.32 mmHg d) 1.00 x 10^3 mmHg e) 5.77 x 10^2 mmHg
d) 1.00 x 10^3 mmHg
You have 49.1g of O2 gas in a container with twice the volume as one with CO2 gas. The pressure and temperature of both containers are the same. Calculate the mass of carbon dioxide gas you have in the container. a) 0.767g b) 67.5g c) 3.07g d) 33.8g e) none of these
d) 33.8g
The density of H2 gas in a rigid container is 0.117g/L at 55C. What is the pressure of hydrogen in the flask if it is heated to 125C? a. 0.142 atm b. 0.194 atm c. 1.56 atm d. 1.90 atm e. 3.55 atm
d. 1.90 atm
What volume of H2O measured at STP is produced by the combustion of 6.46g of natural gas (CH4) in excess oxygen? CH4 + 2O2 -> CO2 + 2H2O a. 4.51L b. 19.7L c. 9.02L d. 18.0L e. 3.23L
d. 18.0L
Methane gas, CH4, effuses through a barrier at a rate of 0.568 mL/min. If an unknown gas effuses through the same barrier at a rate of 0.343mL/minute, what is the molar mass of the gas? a. 20.8 g/mol b. 28.0 g/mol c. 32.0 g/mol d. 44.0 g/mol e. 64.0 g/mol
d. 44.0 g/mol
Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 24.9C a. 15.24 m/s b. 139.3 m/s c. 278.2 m/s d. 481.9 m/s e. 9.177 x 10^26 m/s
d. 481.9 m/s
An unknown gaseous hydrocarbon contains 85.63% C. Its density is 1.524g/L at 0.665atm and 373K. What is the molecular formula of the gas? a. C2H4 b. C3H6 c. C4H8 d. C5H10 e. C6H12
d. C5H10
A gas sample is heated from -20.0C to 57.0C and the volume is increased from 2.00L to 4.50L. If the initial pressure is 0.140atm, what is the final pressure? a) 0.0477 atm b) -0.177 atm c) 0.411 atom d) 0.242 atm e) 0.0811 atm
e) 0.0811
You have a 30.0L cylinder of helium at a pressure of 132 atm and a temperature of 19 C. The He is used to fill balloons to a volume of 1.80L at 745 mmHg and 27C. How many balloons can be filled with He? Assume that the cylinder can provide He until its internal pressure reaches 1.00atm (ie. there are 131 atmospheres of usable He in the cylinder) a) 1.90 x 10^2 b) 1.06 x 10^2 c) 4.13 x 10^3 d) 7.41 x 10^3 e) 2.29 x 10^3
e) 2.29 x 10^3
What volume of oxygen will react with 21 mL of ethanol, assuming the gases are present at the same temperature and pressure? 2CH3CH2OH + 6O2 -> 4CO2 + 6H2O a) 7.0mL b) 14mL c) 21mL d) 42mL e) 63mL
e) 63mL
Absolute zero is the point at which a) a straight-line graph of V versus T(C) intersects the origin b) a straight-line graph of 1/V versus P at constant T intersects the origin c) gaseous helium liquefies d) a straight-line graph of V versus 1/P at constant T intersects the origin e) a straight-line graph of V versus t(K) intersects the origin
e) a straight-line graph of V versus T(K) intersects the origin
Which of the following statements are postulates of the kinetic molecular theory of gases? 1. Gas particles are in constant, random motion 2. The distance between gas particles is large in comparison to their size 3. The average kinetic energy of gas particles is proportional to the Kelvin temperature a. 1 only b. 2 only c. 3 only d. 1 and 2 only e. 1,2, and 3
e. 1, 2 and 3
Which of the following samples contains the fewest moles of gas? a. 1.00L of CH4 at STP b. 1.00L of Ar at -10.0C and 1.0 atm c. 1.00L of NH3 at 10C and 1.0 atm d. 1.00L of H2 at 0C and 1.76 atm e. 1.00L of HCl at 20C and 1.0 atm
e. 1.00L of HCl at 20C and 1.0 atm
Non-ideal behavior for a gas is most likely to be observed under conditions of a. high temperature and low pressure b. high temperature and high pressure c. low temperature and low pressure d. standard temperature and pressure e. low temperature and high pressure
e. low temperature and high pressure
A 10.0L flask at 318K contains a mixture of Ar and Ch4 with a total pressure of 1.040atm. If the mole fraction of Ar is 0.715, what is the mass percent of Ar? a. 13.8% b. 68.8% c. 71.5% d. 82.9% e. 86.2%
e.86.2%
