unit 3 chem

On the basis of the data provided above, the gas in container 3 could be

CH4

The ideal gas law best describes the properties of which of the following gases at 0°C and 1 atm?

N2

A rigid metal tank contains oxygen gas. Which of the following applies to the gas in the tank when additional oxygen is added at constant temperature?

The average speed of the gas molecules remains the same.

The density of the gas, in g/L, is

greatest in container B

A flask contains 0.25 mole of SO2(g), 0.50 mole of CH4(g), and 0.50 mole of O2(g). The total pressure of the gases in the flask is 800 mm Hg. What is the partial pressure of the SO2(g) in the flask?

160 mm Hg

When 6.0 L of He(g) and 10. L of N2(g), both at 0oC and 1.0 atm, are pumped into an evacuated 4.0 L rigid container, the final pressure in the container at 0oC is

4.0 atm

The figure above represents three sealed 1.0 L vessels, each containing a different inert gas at 298 K. The pressure of Ar in the first vessel is 2.0 atm. The ratio of the numbers of Ar, Ne, and He atoms in the vessels is 2:1:6, respectively. After all the gases are combined in a previously evacuated 2.0 L vessel, what is the total pressure of the gases at 298 K?

4.5 atm

Equal masses of He and Ne are placed in a sealed container. What is the partial pressure of He if the total pressure in the container is 6 atm?

5 atm

Under which of the following conditions of temperature and pressure will H2 gas be expected to behave most like an ideal gas?

500 K and 0.10 atm

The pressure, in atm, exerted by 1.85 mol of an ideal gas placed in a 3.00 L container at 35.0°C is given by which of the following expressions?

A ( can't paste equation)

The distribution of speeds of H2(g) molecules at 273 K and 1 atm is shown in the diagram above. Which of the following best shows the speed distribution of He(g) atoms under the same conditions of temperature and pressure?

A ( can't paste image but dashed line spikes up at the beginning)

The gas particles in vessel 3 at 27°C are represented in the diagram above. The lengths of the arrows represent the speeds of the particles. Which of the following diagrams best represents the particles when vessel 3 is heated to 127°C?

A ( can't paste picture)

Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits each statement. A choice may be used once, more than once, or not at all in each set. (A) A network solid with covalent bonding(B) A molecular solid with zero dipole moment(C) A molecular solid with hydrogen bonding(D) An ionic solid(E) A metallic solid Solid ethyl alcohol, C2H5OH

A molecular solid with hydrogen bonding

Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits the statement. A choice may be used once, more than once, or not at all. The following questions refer to the 1 L flasks shown below. In which flask do the molecules have the greatest average speed?

B

Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits the statement. A choice may be used once, more than once, or not at all. The following questions refer to the 1 L flasks shown below. Which flask contains the smallest number of moles of gas?

B

If the pressure of each gas is increased at constant temperature until condensation occurs, which gas will condense at the lowest pressure?

Butane

The table above shows the structural formulas and molar masses for three different compounds. Which of the following is a list of the compounds in order of increasing boiling points?

Butane < acetone < 1-propanol

Directions: Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits the statement. A choice may be used once, more than once, or not at all. The following questions refer to the 1 L flasks shown below. Which flask contains the sample with the greatest density?

C

A 2 L container will hold about 4 g of which of the following gases at 0°C and 1 atm?

CO2

Based on the information in the table above, which liquid, CS2(l) or CCl4(l), has the higher equilibrium vapor pressure at 25°C, and why?

CS2(l), because it has weaker London dispersion forces

Thymine and adenine form a base pair in the DNA molecule. These two bases can form a connection between two strands of DNA via two hydrogen bonds. Which of the following diagrams shows the correct representation of the hydrogen bonding (denoted by dashed lines) between thymine and adenine base pairs? (In each diagram, thymine is shown at the left and adenine is shown at the right. The bases are attached to the backbone portion of the DNA strands.)

D (can't paste image)

The London (dispersion) forces are weakest for which of the following gases under the same conditions of temperature and pressure?

H2

Which of the following behaves most like an ideal gas at the conditions indicated?

H2(g) molecules at 10^-3 atm and 200oC

The diagram above shows molecules of Br2 and I2 drawn to the same scale. Which of the following is the best explanation for the difference in the boiling points of liquid Br2 and I2, which are 59oC and 184oC, respectively?

I2 molecules have electron clouds that are more polarizable than those of Br2 molecules, thus London dispersion forces are stronger in liquid I2.

In solid methane, the forces between neighboring CH4 molecules are best characterized as

London (dispersion) forces

The volume of a sample of air in a cylinder with a movable piston is 2.0 L at a pressure P1, as shown in the diagram above. The volume is increased to 5.0 L as the temperature is held constant. The pressure of the air in the cylinder is now P2. What effect do the volume and pressure changes have on the average kinetic energy of the molecules in the sample?

The average kinetic energy stays the same.

Which of the following best explains the increase in pressure of the C4H10(g)C4H10(g) when its volume is decreased from 0.50L0.50L to 0.21L0.21L ?

The molecules strike the walls of the vessel more frequently.

When a sample of oxygen gas in a closed container of constant volume is heated until its absolute temperature is doubled, which of the following is also doubled?

The pressure of the gas

Based on the data in the table above, which of the following correctly predicts the relative strength of the attraction of Zn2+, Ca2+, and Ba2+ ions to water molecules in a solution, from strongest to weakest, and provides the correct reason?

Zn2+ > Ca2+ > Ba2+ because the smaller ions have a stronger coulombic attraction to water

A 1.0 L sample of a pure gas is found to have a lower pressure than that predicted by the ideal gas law. The best explanation for the observation is that the molecules of the gas

are attracted to each other and do not exert as much force on the container walls as they would if they had no mutual attractions

The best explanation for the fact that diamond is extremely hard is that diamond crystals

are giant molecules in which each atom forms strong covalent bonds with all of its neighboring atoms

At constant temperature, the behavior of a sample of a real gas more closely approximates that of an ideal gas as its volume is increased because the

average distance between molecules becomes greater

At standard temperature and pressure, a 0.50 mol sample of H2 gas and a separate 1.0 mol sample of O2 gas have the same

average molecular kinetic energy

At 298 K and 1 atm, bromine is a liquid with a high vapor pressure, whereas chlorine is a gas. This provides evidence that, under these conditions, the

forces among Br2 molecules are greater than those among Cl2 molecules

Under the conditions given, consider containers 1, 2, and 4 only. The average speed of the gas particles is

greatest in container 1

The best explanation for the lower pressure in container 4 is that SO2 molecules

have stronger intermolecular attractions than the other three gases

Solid carbon tetrachloride, CCl4(s)CCl4(s), is represented by the diagram above. The attractions between the CCl4CCl4 molecules that hold the molecules together in the solid state are best identified as

intermolecular attractions resulting from temporary dipoles

A sample of an unknown gas from a cylinder is collected over water in the apparatus shown above. After all the gas sample has been collected, the water levels inside and outside the gas collection tube are made the same. Measurements that must be made to calculate the molar mass of the gas include all of the following EXCEPT

mass of the water in the apparatus

Questions refer to three gases in identical rigid containers under the conditions given in the table below. The average kinetic energy of the gas molecules is

the same in all three containers

When the actual gas volume is greater than the volume predicted by the ideal gas law, the explanation lies in the fact that the ideal gas law does NOT include a factor for molecular.

volume