Final

The elements I and Te have similar average atomic masses. A sample that was believed to be a mixture of I and Te was run through a mass spectrometer, resulting in the data below. All of the following statements are true. Which one would be the best basis for concluding that the sample was pure Te

"I" consists of only one naturally occurring isotope with 74 neutrons, whereas Te has more than one isotope.

How many carbon atoms are contained in 2.8 g of C2H4

1.2 x 1023

Which of the following is the correct electron configuration for the F- ion

1s22s22p6

Which of the following represents the correct electron configuration for the Fe3+ ion

1s22s22p63s23p63d5

When 4.0 L of He (g), 6.0 L of N2 (g) and 10. L of Ar (g), all at 0 degrees Celsius and 1.0 atm, are pumped into an evacuated 8.0 L rigid container, the final pressure in the container at 0 degrees Celsius is

2.5 atm

Based on the periodic trends and the data in the table below, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively

242 pm, 419 kJ/mol

The figure below 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, which is the total pressure of the gases at 298 K

4.5 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

To choose a wavelength

590 nm, because only the violet form of the molecule will absorb significantly at this wavelength.

Based on the information below and periodic trends, which of the following is the best hypothesis regarding the oxide(s) formed by Rb

All three

Which of the following correctly identifies which has the higher first ionization energy, Cl or Ar, and supplies the best justification

Ar, because of its higher effective nuclear charge.

The first five ionization energies of a second period element are listed in the table below. Which of the following correctly identifies the element and best explains the data in the table

B, because it has three valence electrons.

Which element below has the highest electronegativity

Br

The molecular formula and molar mass of two straight-chain hydrocarbons are listed in the table below. Based on the information in the table, which compound has the higher boiling point and why is that compound's boiling point higher

C4H10; because it has more electrons, resulting in greater polarizability and stronger dispersion forces.

Based on the data in the table below, which of the following liquid substances has the weakest intermolecular forces

CH3OH (l)

A sample of a compound that contains only the elements C, H, and N is completely burned in O2 to produce 44.0 g of CO2, 45.0 g of H2O, and some NO2. A possible empirical formula of the compound is

CH5N

Equal volumes of solutions in two different vessels are represented below. If the solution represented in vessel 1 is KCl (aq), then the solution represented in vessel 2 could be an aqueous solution of

CaCl2 with twice the molarity as the solution in vessel 1

Which element is represented in the photoelectron spectrum shown below

Cl

Which of the following lists Mg, P and Cl in order of increasing atomic radius

Cl < P < Mg

In which of the following compounds is the mass ratio of chromium to oxygen closest to 1.62 to 1.00

CrO2

The diagram below represents the absorption spectrum for a pure molecular substance. Which of the following correctly indicates the type of transition observed for the substance in each of the regions of the absorption spectrum

D

Three substances were studied in the laboratory, and the data in the table above were collected. Based on the data, which of the following shows the type of bonding in each substance

D

Which of the following best helps to account for the fact that the F- ion is smaller in size than the O2- ion

F- has a larger nuclear charge than O2- has.

The Maxwell-Boltzmann distributions of molecular speeds in samples of two different gases at the same temperature are shown below. Which gas has the greater molar mass

Gas A

Which of the substances listed below has the highest boiling point, and why

HF, because its molecules form hydrogen bonds

A 0.5 mol sample of He(g) and a 0.5 mol sample of Ne(g) are placed separately in two 10.0 L rigid containers at 250C. Each container has a pinhole opening. Which of the gases, He (g) or Ne (g), will escape faster through the pinhole and why

He will escape faster because the He atoms are moving at a higher average speed than the Ne atoms.

Which of the following is the strongest type of interaction that occurs between the atoms within the circled areas of the two molecules represented below

Hydrogen bond

The complete photoelectron spectrum for an element is shown below. Which of the following observations is true regarding the element shown in the spectrum

In its compounds, the element tends to form ions with a charge of +1.

The diagram below 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 59 degrees C and 184 degrees C, respectively

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

The graph below shows the speed distribution of molecules in a sample of a gas at a certain temperature. Which of the following graphs shows the speed distribution of the same molecules at a higher temperature (as a dashed curve)

Lowest hanging

According to the information in the table below, a 1.00 g sample of which of the following contains the greatest mass of oxygen

MgO

Elements of atom X have the electron configuration shown below. The compound most likely formed with magnesium is

MgX

Which of the following diagrams best represents a solution of silver nitrate AgNO3

Mickey facing out of NO3, Mickey facing into Ag

Which gas behaves the MOST like an ideal gas

N2

On the basis of molecular structure and bond polarity, which of the following compounds is most likely to have the greatest solubility in water

NH3

Based on the data in the tables below, which of the following statements provides the best prediction for the boiling point of NaCl

NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF.

The photoelectron spectra below show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum

Nitrogen atoms have a smaller nuclear charge than oxygen atoms.

Consider atoms of the following elements. Assuming that the atoms are in the ground state (electrons fill up in the correct order), the atom that contains exactly two unpaired electrons is

S

Which of the following gases has the slowest average speed

SO2

If a pure sample of an oxide of sulfur contains 40. percent sulfur and 60. percent oxygen by mass, then the empirical formula of the oxide is

SO3

The masses of carbon and hydrogen in samples of four pure hydrocarbons are given below. The hydrocarbon in which sample has the same empirical formula as C3H6

Sample B

Which of the following ions has the same number of electrons as Br -

Sr2+

The volume of a sample of air in a cylinder with a movable piston is 2.0 L at a pressure of P1, as shown in the diagram below. The volume is increased to 5.0 L as the temperature is held constant. The pressure of teh air in the cylinder is now P2. Which 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

A sample of a solid labeled as NaCl may be impure. A student analyzes the sample and determines that it contains 75 percent chlorine by mass. Pure NaCl (s) contains 61 percent chlorine by mass. Which of the following statements is consistent with the data

The sample contains NaCl (s) and LiCl (s).

The ionization energies of an unknown element, X are listed in the table below. Which of the following is the most likely empirical formula of a compound formed from element X and phosphorous, P

X3P2

In a paper chromatography experiment, a sample of pigment is separated into two components, X and Y, as shown in the figure below. The surface of the paper is polar. What can be concluded about X and Y based on the experimental results

Y is more polar than X.

The mass spectrum of an average sample of a pure element is shown in the figure above. Which of the following is the identity of the element

Zr

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.