Chem 1 test 2
a sample gas of H2 gas 12.28 occupies a 100l at 400 k and 2.00atm a sample weighing 9.49 occupies _____L at 353K and 2 atm
68.2
Which would have a density of 1.21g/L at 7.0°C and 0.987atm? F2 N2 Ne Ar O2
Ar
a ballon contains .33 mol N2 .091 mol O2.0301 mol Ar .060 mol he
4.6 X10^2
When gases are treated as real, via use of the van der Waals equation, the actual volume occupied by gas molecules __________ the pressure exerted and the attractive forces between gas molecules __________ the pressure exerted, as compared to an ideal gas. increases, increases decreases, increases does not affect, increases does not affect, decreases increases, decreases
increases, decreases
when gasses are treated as real via bad Der walls equation the actual volume occupied by the gas molecules __________ the pressure exerted and the attractive forces between gas molecules ________ the pressure exerted as comparred to and ideal gas increases, decreases does not affect decreases decreases increases increases, increases does not affect increases
increases, decreases
why don we draw a double bond between be atom and Cl BeCl2
it would result in more than eight electrons around the chlorine atom
_________ molecules are polarizable
large molecules regardless of their polarity
as a solid melts, the atoms become_________ and they have ______ attraction for one another
more separated, less
The total pressure of a mixture of gases is . . . dependent only upon the pressure of the gas present with the greatest pressure. the sum of the partial pressures of the components. obtained by multiplying the individual pressures by the number of moles and averaging. something else the product of the individual pressures.
obtained by multiplying the individual pressures by the number of moles and averaging.
in general, the vapor pressure of a substance increases as __________ increases. hydrogen bonding temperature surface tension molecular weight viscosity
temperature
Which one of the following exhibits dipole-dipole attraction between molecules? BCl3 AsH3 XeF4 Cl2 CO2
AsH3
into a 500 ml container is placed 100 ml of no at STP with 400mL of O2 at STP. The container is sealed and the reaction goes to completion. what is the partial pressure of NO2 2 NO + O2---> 2NO2
.222 atm
n a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is __________ if the partial pressures of He and Ne are 1.50 and 2.00 atm, respectively. 0.357 0.417 0.238 0.179 0.583
.583
A sample of a gas (5.0 mol) at 1.0 atm is expanded at constant temperature from 10 L to 15 L. The final pressure is __________ atm. 15 1.5 3.3 0.67 7.5
.67
Which of the following equalities shows an incorrect relationship between pressures given in terms of different units? 1.00 atm = 760 torr 1.00 torr = 2.00 mm Hg 1.20 atm = 122 kPa 0.760 atm = 578 mm Hg 152 mm Hg = 2.03×104 Pa
1.00 torr =2.00 mm Hg
At STP, the ratio of the root-mean-square speed of CO2 to that of SO2 is __________. 1.207 2.119 1.456 2.001 1.000
1.207
The volume of a ballon is_______ L at a depth of 5.2 meters if its volume on the surface of water 2.58l .10.08meters of water equals one atmosphere
1.70
The national weather service routinely supplies atmospheric pressure 30.51inches
103.3
chloroform is a volatile liquid once commonly used in the laboratory. I f the pressure of gases chloroform in a flask of 195 mmhm at 25C and its density 1.25 what is molar mass
119
A closed-end manometer was attached to a vessel containing argon. The difference in the mercury levels in the two arms of the manometer was 12.2 cm. Atmospheric pressure was 783 mmHg. The pressure of the argon in the container was __________ mmHg. 795 661 882 771 122
122
A sample of gas (24.2 g) initially at 4.00 atm was compressed from 8.00 L to 2.00 L at constant temperature. After the compression, the gas pressure was __________ atm. 8.00 16.0 1.00 2.00 4.00
16
Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. coefficient of aluminum?
2 oxidation states
A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF to the rate of effusion of HBr is __________. 2.01 0.247 4.04 16.3 0.497
2.01
A 1.000kg sample of nitroglycerin explodes in a 600.L container and releases gases with a temperature of 1985.°C at 10.0atm; what is the pressure of nitrogen gas? 4 C3H5N3O9(s) → 12 CO2(g) + 10 H2O(g) + 6 N2(g) + 1 O2(g) something else 2.07 atm 10.0 atm 60 atm 18.2 atm
2.07
A sample of a gas originally at 25°C and 1.00 atm pressure in a 2.5 L container is allowed to expand until the pressure is 0.85 atm and the temperature is 15°C. The final volume of the gas is __________ L. 0.38 3.0 2.6 2.8 2.1
2.8
The pressure in a 12.2 L vessel that contains 2.34 g of carbon dioxide, 1.73 g of sulfur dioxide, and 3.33 g of argon, all at 42°C is __________ mmHg. 395 0.347 263 116 134
263
Standard temperature and pressure (STP), in the context of gases, refers to __________. 273 K and 1 Pa 298 K and 1 torr 298 K and 1 atm 273 K and 1 torr 273 K and 1 atm
273 K and 1 atm
Since air is a mixture, it does not have a "molar mass." However, for calculation purposes, it is possible to speak of its "effective molar mass." (An effective molar mass is a weighted average of the molar masses of a mixture's components.) If air at STP has a density of 1.285 g/L, what is its effective molar mass? 31.4 g/mol 28.8 g/mol 26.9 g/mol 34.4 g/mol 30.0 g/mol
28.8
A sample of oxygen gas was found to effuse at a rate equal to three times that of an unknown gas. The molecular weight of the unknown gas is __________ g/mol. 4 10.7 288 55 96
288
The molecular weight of a gas is __________ g/mol if 3.5 g of the gas occupies 2.1 L at STP. 5.5×103 3.7×101 2.7×10−2 4.6×102 41
3.7 x 10^1
A 1.000kg sample of nitroglycerin explodes and releases gases with a temperature of 1985.°C at 1.00atm; what is the volume of gas produced? 4 C3H5N3O9(s) → 12 CO2(g) + 10 H2O(g) + 6 N2(g) + 1 O2(g) 6.82×103 L 7.79×103 L 5.21×103 L something else
5.21 x 103L
The root-mean-square speed of CO at 113°C is __________ m/s. 586 993 217 58.3 31.5
586
A 0.286g sample of gas occupies 125.0mL at 600.0mm Hg and 25.0°C; what is the molar mass of the gas? (Round to two significant figures!) 44. g/mol 3.7 ×105 g/mol 59. g/mol 71. g/mol 93. g/mol 1.0 ×10−5 g/mol
71
A pressure of 1.00 atm is the same as a pressure of __________ of mmHg. 760.0 29.9 101 33.0 193
760
In ideal gas equation calculations expressing pressure in pascals nesscitates the use of gas constant R equal to
8.314
Of the following gases, __________ has density of 2.104 g/L at 303 K and 1.31 atm. He Kr Xe Ar Ne
Ar
for a molecule of general vesper notation AxnEm the n+m can be greater than 4 only when
A is an element of the third row or below
Which of the following statements about gases is false? Non-reacting gas mixtures are homogeneous. Gases expand spontaneously to fill the container they are placed in. Distances between molecules of gas are very large compared to bond distances within molecules. Bases are highly compressible. All gases are colorless and odorless at room temperature.
All gases are colorless and odorless at room temperature.
One significant difference between gases and liquids is that __________. All of the above answers are correct. a gas assumes the volume of its container a gas is made up of molecules a gas may consist of both elements and compounds gases are always mixtures
B. a gas assumes the volume of its container
Based on molecular mass and dipole moment of the five compounds in the table below, which should have the highest boiling point? Substance Molecular Mass (amu) Dipole Moment (Debye) Propane, CH3CH2CH3 44 0.1 Dimethylether, CH3OCH3 46 1.3 Methylchloride, CH3Cl 50 1.9 Acetaldehyde, CH3CHO 44 2.7 Acetonitrile, CH3CN 41 3.9
CH3CN
Which one of the following substances will not have hydrogen bonding as one of its intermolecular forces? HOOH CH3NH2 CH3CH2OH NH2NH2 CH3COCH3
CH3COCH3
Of the following substances, only __________ has London dispersion forces as its only intermolecular force. NH3 HCl H2S CH4 CH3OH
CH4
At 333 K, which of the pairs of gases below would have the most nearly identical rates of effusion? N2 and O2 CO and N2 N2O and NO2 CO and CO2 NO2 and N2O4
CO N2
A solid has a very high melting point great hardness and poor electrical conduction this is an ________ solid
Covalent network
According to kinetic-molecular theory, in which of the following gases will the root-mean-square speed of the molecules be the highest at 200°C? HCl None. The molecules of all gases have the same root-mean-square speed at any given temperature. SF6 H2O Cl2
H2O
what is the dominant intermolecular force in CBr4
London dispersion fources
What two properties of real gases cause deviation from ideal behavior? You Answered P and T P and n P and V V and T n and T
P and V
a_______ covalent bond is the largest
Single
one significant differnce between gas and liquids is a a gas may consist of both elements and compounds all the suggested a gas is a mixture of molecules a gas assumes the volume of its container
a gas assumes the volume of its container
Large intermolecular forces in a substance are manifested by low vapor pressure high boiling point high heats of fusion and vaporization high critical temperatures and pressures all suggested affects
all suggested affects
The kinetic-molecular theory predicts that pressure rises as the temperature of a gas increases because __________. the average kinetic energy of the gas molecules decreases ! both the gas molecules collide more frequently with the wall and the gas molecules collide more energetically with the wall the gas molecules collide less frequently with the wall the gas molecules collide more energetically with the wall the gas molecules collide more frequently with the wall
both the gas molecules collide more frequently with the wall and the gas molecules collide more energetically with the wall
On a phase diagram, the liquid-solid segment corresponds to the solid phase subliming. corresponds to the liquid phase melting. corresponds to the critical temperature and pressure. corresponds to the solid phase melting. corresponds to the conditions of temperature and pressure under which the solid and the liquid of the substance are in equilibrium.
corresponds to the conditions of temperature and pressure under which the solid and the liquid of the substance are in equilibrium.
The principal source of the difference in the normal boiling points of ICI 97c molecular mass 162
dipole-dipole
Hydrogen bonding is a special case of __________. ion-ion interactions Something else ion-dipole attraction dipole-dipole attractions London-dispersion forces
dipole-dipole attractions
Volatility and vapor pressure are __________. not related inversely proportional to one another directly proportional to one another both independent of temperature the same thing
directly proportional to one another
Kinetic-molecular theory assumes that __________. attractive and repulsive forces between gas particles are stronger than those between gas particles and container walls the collisions between gas particles are inelastic gases consist of tiny particles in constant, random motion the average kinetic energy of the particles of a gas is directly proportional to the Celsius temperature
gases consist of tiny particles in constant, random motion
Crystalline solids __________. exist only at high temperatures are usually very soft have highly ordered structures exist only at very low temperatures have their particles arranged randomly
have highly ordered structures
An ideal gas differs from a real gas in that the molecules of an ideal gas.
have no attraction to one another
For which of the following changes is it not clear whether the volume of a particular sample of an ideal gas will increase or decrease? increase the temperature and decrease the pressure decrease the temperature and increase the pressure increase the temperature and keep the pressure constant increase the temperature and increase the pressure keep temperature constant and decrease the pressure
increase the temperature and increase the pressure
In liquids, the attractive intermolecular forces are __________. A) very weak compared with kinetic energies of the molecules B) strong enough to hold molecules relatively close together C) strong enough to keep the molecules confined to vibrating about their fixed lattice points D) not strong enough to keep molecules from moving past each other E) strong enough to hold molecules relatively close together but not strong enough to keep molecules from moving past each other
strong enough to hold molecules relatively close together but not strong enough to keep molecules from moving past each other
On a phase diagram, the critical pressure is __________. the pressure required to liquefy a gas at its critical temperature the pressure below which a substance is a solid at all temperatures the pressure above which a substance is a liquid at all temperatures the pressure required to melt a solid the pressure at which a liquid changes to a gas
the pressure required to liquefy a gas at its critical temperature
