Bhemistry 1

CO2

A 22.0 gram sample of an unknown gas occupies 112 liters at standard temperature and pressure. Whcih of the following could be the identity of the gas?

(.08)(299) g/mol

A gas sample with a mass of 10 grams occupies 5.0 liters and exerts a pressure of 2.0 atm at a temperature of 26 C. Which of the following expressions is equal to the molecular mass of the gas? The gas constant, R, is 0.08 (L*atm)/(mol*K)

758 mmHg

A mixture of helium and neon gases has a total pressure of 1.2 atm. If the vapor pressure of water at 25 C is 23 mmHg., and the total pressure in the container is measured at 781 mmHg, what is the partial pressure of the nitrogen gas?

C3H6O

A sample of a compound known to consist of only carbon, hydrogen, and oxygen is found to have a total mass of 29.05 g. If the mass of the carbon is 18.02 g and the mass of the hydrogen is 3.03 g, what is the empirical formula of the compound?

The hydrogen bonds holding separate NH3 molecules together break apart.

A sample of liquid NH3 is brought to its boiling point. Which of the following occurs during the boiling process?

0.50 atm

A sealed rigid container contains three gases: 28.0 g of nitrogen, 40.0 g of argon, and 36.0 g of water vapor. If the total pressure exerted by the gases is 2.0 atm, what is the partial pressure of the nitrogen?

Z>X>Y

A strip of metal X is placed into a solution containing Y^2+ ions and no reaction occurs. When metal X is placed in a separate solution containing

3p

An atom of silicon in its ground state is subjected to a frequency of light that is high enough to cause electron ejection. An electron from which subshell of silicon would have the highest kinectic energy after ejection?

The peak at 1.76 MJ/mol

An electron from which peak would have the greatest velocity after ejection

3.36 L

Approximately how many liters of oxygen gas will be evolved at STP?

The O2 molecules, because they have the least mass

At a given point in the reaction, all three gases are present at the same temperature. Which gas molecules will have the highest velocity and why?

The existence of isotopes

Examining data obtained from mass spectrometry supports which of the following?

It is above the energy level of both the products and reactants

For an endothermic reaction, which of the following is true regarding the energy level of the activated complex

5

How many valence electrons does this atom have?

4.5 eV

How much energy did photons of the incoming light contain?

4.80 g

If 12.25 g of potassium chlorate decomposes, how many grams of oxygen gas will be generated?

Cl-

If equimolar solutions of Pb(NO3)2 and NaCl are mixed, which ion will not be present in significant amounts in the resulting solution after equilibrium is established?

Fe2(Co3)3

If solutions fo Iron (III) nitrate and sodium carbonate are mixed, what would be the formula of the precipitate?

The decreased intensity would have no effect.

If the intensity of the light were to be decreased (that is, if the light is made dimmer), how would that affect the kinetic energy of the ejected electron?

K^+ and NO3^-

If the solutions containing equal amounts of AGNO3 and KCl are mixed, what is the identity of the spectator ions?

It will also double, because the gas molecules will be moving faster.

If the temperature of the gas is doubled while the volume is held constant, what will happen to the pressure exerted by the gas and why?

80%

If the temperature remains constant, what percentage of the original pressure will the final pressure in the container be equal to?

A shorter wavelength would increase the kinetic energy.

If the wavelength of the light were to be shortened, how would that affect the kinetic energy of the ejected electron?

Nonmetals have higher ionization energies because they are closer to having filled a complete energy level.

In general, do metals or nonmetals from the same period have higher ionization energies? Why?

CrO4^2-

In which of the following compounds is the oxidation number of chromium the greatest?

Nitrite has shorter and stronger bonds than nitrate.

Lewis diagrams for the nitrate and nitrite ions are shown below. Choose the statement that correctly describes the relationship between the two ions in terms of bond length and bond energy.

The electronegativity value will be greatest in element Z.

The diagram below shows the relative atomic sizes of three different elements from the same period. Which of the following statements must be true?

Ca has two electron\s in the outer shell second larger than first, the third will be hard to take as its removed from lower energy level than before higher ionization energy.

The first and second ionization energies for calcium are comparable, but the third ionization energy is much greater.

It would be less than both because a valence electron of potassium is farther from the nucleus than one of either chlorine or argon.

The first ionization energy for a neutral atom of chlorine is 1.25 MJ/mol and the first ionization energy for a neutral atom of argon is 1.52 MJ.mol. How would the first ionization energy value for a neutral atom of potassium compare to those values?

Valence electron from Mg is in 3s while Al is in 3p. It is easier to remove from the higherr energy level than the completed lower 3s subshell.

The first ionization energy for aluminum is lower than the first ionization energy for magnesium.

Methanol

The following diagrams show the structures of four different molecules. Which molecule would travel the farthest in a paper chromatography experiment using a polar solvent?

Magnesium

The ionization energies for an element are listed in the table below. Based on the ionization energy table, the element is most likely to be

Ultraviolet has more energy because it has a higher frequency.

The wavelength range for infrared radiation is 10^-5 m, while that of ultraviolet radiation is 10^-8 m. Which type of radiation has more energy, and why?

Low temperatures, because the intermolecular forces between the gas molecules would increase

Under which of the following conditions would the gases in the container most deviate from ideal conditions and why?

Phosphorus

What element does this spectra represent?

64 grams

What is the mass of oxygen in 148 grams of calcium hydroxide (Ca(OH)2)?

0.33

What is the mole fraction of neon in the container?

1s^2 2s^2 2p^6

What is the most likely electron configuration for a sodium ion?

33.5 L

What is the volume of the container?

Hydrogen, because it has a lower molar mass

Which gas particles have a higher RMS velocity and why?

Manganese

Which neutral atom of the following elements would have the most unpaired electrons

MgCl2

Which of the following compounds have the highest lattice energy?

K^+

Which of the following isoelectric species has the smallest radius?

37Cl

Which of the following nuclei has 3 more neutrons than protons? (Remember: The number before the symbol indicates atomic mass.)

Aluminum and lead

Which of the following pairs of elements is most likely to create an interstitial

Chlorine has greater electronegativity and a larger first ionization energy.

Which of the following statements is true regarding sodium and chlorine?

SF4

Which of the following substances has an asymmetrical molecular structure?

4 SO3 4O2

Which particulate drawing best represents the contents of the flask after the reaction goes to completion?

The peak at 6.84 MJ/mol

Which peak represents the 2s?

Nitrogen only has two energy levels and is thus unable to expand its octet.

Why can a molecule with the structure of NBr5 not exist?

The electrons in P^3- have a greater Coulombic repulsion than those in the neutral atom.

Why does an ion of phosphorus, P^3-, have a larger radius than a neutral atom of phosphorus?