Chapter 8,9 &10

A sample of oxygen gas has a volume of 3.52 L at 27°C and 800.0 torr. How many oxygen molecules does it contain? a) 9.06 1022 b) 6.88 1025 c) 1.01 1024 d) 4.00 1024 e) none of these

A

Based on electronegativity differences, which of the following is most likely to be ionic? a) BaF2 b) Br2 c) PH3 d) NO2 e) CI4

A

Which of the following has the smallest radius? a) K+ b) Cl- c) Rb+ d) S2- e) Ar

A

The standard temperature for gases is a) 100ºC b) 0ºC c) 32ºC d) 212ºF e) 0ºF

B

When nonmetals chemically combine, they tend to form what type of bond?

COVALENT

A sample of helium gas occupies 19.5 L at 23°C and 0.956 atm. What volume will it occupy at 40°C and 1.20 atm? a) 25.9 L b) 27.0 L c) 14.7 L d) 16.4 L e) 19.7 L

D

In the Lewis structure for ICl2 -, how many lone pairs of electrons are around the central iodine atom? a) 0 b) 1 c) 2 d) 3 e) 4

D

In the Lewis structure for SF6, the central sulfur atom shares __________ electrons. a) 4 b) 8 c) 10 d) 12 e) None of the above, because SF6 is an ionic compound.

D

PF5 a) linear b) trigonal planar c) tetrahedral d) bent e) none of these

E

T F A nonpolar covalent bond results from the unequal sharing of a pair of electrons between atoms in a molecule.

F

T F At the same temperature, lighter molecules have a higher average kinetic energy than heavier molecules.

F

T F The Lewis structure for CHCl3 has nine lone electron pairs.

T

T F The shape of a carbon dioxide molecule is linear.

T

The ability of an atom in a molecule to attract shared electrons to itself is called __________.

electronegativity

A molecule that has a center of positive charge and a center of negative charge is said to be __________.

polar

Choose the molecule with the strongest bond. a) HF b) HCl c) HBr d) HI e) All are equal.

A

Choose the statement that best describes the PbCl4 molecule in the gas phase. a) The bond angles are all about 109°. b) The molecule is polar. c) The molecule has a dipole moment. d) The bonds are nonpolar. e) More than one of the above.

A

Gases generally have a) low density b) high density c) closely packed particles d) no increase in volume when temperature is increased e) no decrease in volume when pressure is increased

A

If M is the molar mass, R the gas constant, T the temperature, and P its pressure, which of the following expressions represents the density of a gas? a) PM RT b) RM PT c) RMP T d) RTM Pe) M RT P

A

In the gaseous phase, which of the following diatomic molecules would be the most polar? a) CsF b) CsCl c) NaCl d) NaF e) LiF

A

Of the following real gases, which would be expected to have the lowest van der Waals correction for intermolecular attractions? a) H2 b) CO2 c) NH3 d) O2 e) not enough information to determine

A

The Cl-Kr-Cl bond angle in KrCl4 is closest to a) 90° b) 109° c) 120° d) 150° e) 360°

A

The force between two bodies having identical electric charges a) is a force of repulsion b) is a force of repulsion if the charges are negative, and one of attraction if they are positive c) increases as the bodies are moved further apart d) is independent of the distance between them e) is directly proportional to the distance between them

A

The molecular structure of NCl3 is a) a) pyramidal b) b) none of these c) c) octahedral d) d) trigonal planar e) e) bent

A

The molecular structure of SOCl2 is a) a) pyramidal b) b) none of these c) c) octahedral d) d) trigonal planar e) e) bent

A

Which of the following atoms cannot exceed the octet rule in a molecule? a) N b) S c) P d) I e) All of the atoms (A-D) can exceed the octet rule.

A

Which of the following compounds contains only one unshared pair of valence electrons? a) NH3 b) H2O c) CH4 d) NaCl e) BF3

A

Which of the following is not a postulate of the kinetic molecular theory? a) Gas particles have most of their mass concentrated in the nucleus of the atom. b) The moving particles undergo perfectly elastic collisions with the walls of the container. c) The forces of attraction and repulsion between the particles are insignificant. d) The average kinetic energy of the particles is directly proportional to the absolute temperature. e) All of the above are postulates of the kinetic molecular theory.

A

Which of the following molecules contains a double bond? a) CO2 b) NH3 c) H2O d) all e) none

A

Which of the following molecules has no dipole moment? a) CO2 b) NH3 c) H2O d) all e) none

A

Which of the following properties of a real gas is related to the b coefficient in the van der Waals equation? a) Real gases consist of molecules or atoms that have volume. b) The average speed of the molecules of a real gas increases with temperature. c) There are attractive forces between atoms or molecules of a real gas. d) The rate of effusion of a gas is inversely proportional to the square root of the molecular weight of the gas. e) None of these.

A

A balloon has a volume of 2.36 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new volume of the balloon. a) 2.36 L b) 2.55 L c) 2.18 L d) 4.72 L e) 1.18 L

B

A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6°C. Determine the temperature at which the volume of the gas is 3.45 L. a) 309 K b) 281 K c) 20.6 K d) 295 K e) 554 K

B

According to the postulates of the kinetic theory of gases, the average speed of the molecules of a given gas is proportional to the a) absolute temperature squared b) square root of the absolute temperature c) absolute temperature d) Celsius temperature squared e) reciprocal of the absolute temperature

B

Based on electronegativities, which of the following would you expect to be most ionic? a) N2 b) CaF2 c) CO2 d) CH4 e) CF4

B

Body temperature is about 309 K. On a cold day, what volume of air at 271 K must a person with a lung capacity of 1.5 L breathe in to fill the lungs? a) 1.71 L b) 1.32 L c) 1.40 L d) 2.63 L e) none of these

B

Choose the compound with the most ionic bond. a) LiCl b) KF c) NaCl d) LiF e) KCl

B

For the elements Cs, F, and Cl, the order of increasing electronegativity is: a) F < Cl < Cs b) Cs < Cl < F c) Cl < Cs < F d) F < Cs < Cl e) none of these

B

For the elements Cs, F, and P, the order of increasing electronegativity is: a) Cs < F < P b) Cs < P < F c) P < F < Cs d) F < Cs < P e) none of these

B

Hydrogen and chlorine gases react to form HCl. You and a friend are on opposite sides of a long hallway, you with H2 and your friend with Cl2. You both want to form HCl in the middle of the room. Which of the following is true? a) You should release the H2 first. b) Your friend should release the Cl2 first. c) You both should release the gases at the same time. d) You need to know the length of the room to answer this question. e) You need to know the temperature to answer this question.

B

In which of the following compounds does the bond between the central atom and bromine have the greatest ionic character? a) LiBr b) KBr c) SeBr2 d) AsBr3 e) CaBr2

B

Metals typically have _______ electronegativity values. a) high b) low c) negative d) no e) two of these

B

Real gases are those that a) only behave ideally at high pressures or low temperatures b) deviate from ideal behavior c) are only available naturally in the earth's atmosphere d) are called real gases because their behavior can easily be modeled e) have an even number of protons

B

Standard pressure for gases is a) 0 atm b) 1 atm c) 100 atm d) dependent upon temperature e) none of the above

B

The electron pair in a C-F bond could be considered a) closer to C because carbon has a larger radius and thus exerts greater control over the shared electron pair b) closer to F because fluorine has a higher electronegativity than carbon c) closer to C because carbon has a lower electronegativity than fluorine d) an inadequate model since the bond is ionic e) centrally located directly between the C and F

B

The van der Waals equation, nRT = [P + a(n/V)2] (V - nb), incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for a) the possibility of chemical reaction between molecules b) the finite volume of molecules c) the quantum behavior of molecules d) the fact that average kinetic energy is inversely proportional to temperature e) the possibility of phase changes when the temperature is decreased or the pressure is increased

B

Use the kinetic molecular theory of gases to predict what would happen to a closed sample of a gas whose temperature increased while its volume decreased. a) Its pressure would decrease. b) Its pressure would increase. c) Its pressure would hold constant. d) The number of moles of the gas would decrease. e) The average kinetic energy of the molecules of the gas would decrease.

B

What would happen to the average kinetic energy of the molecules of a gas sample if the temperature of the sample increased from 20°C to 40°C? a) It would double. b) It would increase. c) It would decrease. d) It would become half its value. e) Two of these.

B

Which ion is planar? a) NH4+ b) CO32- c) SO32- d) ClO3- e) all are planar

B

Which of the following is included as a postulate in the kinetic molecular theory of an ideal gas? a) The distance between gas molecules is small compared with the size of the molecule. b) All collisions between molecules are elastic. c) In an average collision between molecules, both molecules have the same kinetic energy. d) All molecules move randomly in zigzag directions. e) All the molecules have the same velocity.

B

Which of the following is true about the kinetic molecular theory? a) The volume of a gas particle is considered to be small - about 0.10 mL. b) Pressure is due to the collisions of the gas particles with the walls of the container. c) Gas particles repel each other, but do not attract one another. d) Adding an ideal gas to a closed container will cause an increase in temperature. e) At least two of the above statements are correct.

B

Which of the following pairs is isoelectronic? a) Li+ and K+ b) Na+ and Ne c) I- and Cl- d) S2- and Ne e) Al3+ and B3+

B

Which of these is an isoelectronic series? a) Na+, K+, Rb+, Cs+ b) K+, Ca2+, Ar, S2- c) Na+, Mg2+, S2-, Cl- d) Li, Be, B, C e) none of these (A-D)

B

A 4.82-L sample of carbon monoxide is collected at 55°C and 0.833 atm. What volume will the gas occupy at 1.05 atm and 25°C? a) 1.74 L b) 5.52 L c) 3.47 L d) 4.21 L e) none of these

C

All the following are postulates of the kinetic-molecular theory of gases except: a) The collisions between molecules are elastic. b) The gas molecules are in constant motion. c) At a constant temperature, each molecule has the same kinetic energy. d) The volumes of the molecules are negligible compared with the volume of the container. e) The gas molecules are in rapid motion.

C

As the number of bonds between two carbon atoms increases, which one of the following decreases? a) number of electrons between the carbon atoms b) bond energy c) bond length d) all of these e) none of these

C

Atoms having equal or nearly equal electronegativities are expected to form a) no bonds b) polar covalent bonds c) nonpolar covalent bonds d) ionic bonds e) covalent bonds

C

Calculate the root mean square velocity for the O2 molecules in a sample of O2 gas at 32.3°C. (R = 8.3145 J/Kmol) a) 158.7 m/s b) 15.43 m/s c) 487.8 m/s d) 281.6 m/s e) 9.290 1026 m/s

C

For an ideal gas, which pairs of variables are inversely proportional to each other (if all other factors remain constant)? 1. P and T 2. T and n 3. n and P 4. V and T a) 1 and 2 only b) 3 and 4 only c) 2 only d) 1 and 3 only e) 1, 3, and 4 only Ans: c

C

The molecular structure of BrF6+ is a) a) pyramidal b) b) none of these c) c) octahedral d) d) trigonal planar e) e) bent

C

Which of the following molecules has a nonlinear structure? a) XeF2 b) BeCl2 c) O3 d) CO2 e) N2O (central atom is N)

C

Which of the following pollutant gases is not produced directly in a combustion engine? a) CO b) CO2 c) O3 d) NO e) NO2

C

Which of the following species would be expected to have the lowest ionization energy? a) F- b) Ne c) O2- d) Mg2+ e) Na+

C

Which of the following statements is true concerning ideal gases? a) The temperature of the gas sample is directly related to the average velocity of the gas particles. b) At STP, 1.0 L of Ar(g) contains about twice the number of atoms as 1.0 L of Ne(g) since the molar mass of Ar is about twice that of Ne. c) A gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container. d) The gas particles in a sample exert attraction for one another. e) All of the above are false.

C

Which statement is inconsistent with the kinetic theory of an ideal gas? a) The forces of repulsion between gas molecules are very weak or negligible. b) Most of the volume occupied by a gas is empty space. c) When two gas molecules collide, they both gain kinetic energy. d) The average kinetic energy of a gas is proportional to the absolute temperature. e) Gas molecules move in a straight line between collisions.

C

You fill a balloon with 2.50 moles of gas at 24°C at a pressure of 1.78 atm. What is the volume of the balloon? a) 17.4 L b) 108 L c) 34.2 L d) 2.77 L e) 22.4 L

C

According to the VSEPR model, the arrangement of electron pairs around NH3 and CH4 is a) different, because in each case there are a different number of atoms around the central atom b) different, because in each case there are a different number of electron pairs around the central atom c) the same, because both nitrogen and carbon are both in the second period d) the same, because in each case there are the same number of electron pairs around the central atom e) different or the same, depending on the conditions leading to maximum repulsion

D

Atoms with greatly different electronegativity values are expected to form a) no bonds b) covalent bonds c) triple bonds d) ionic bonds e) none of these

D

Choose the molecule with the strongest bond. a) CH4 b) H2O c) NH3 d) HF e) All are equal

D

Complete the following: Because real gas particles have attraction for one another: a) Real gases act most ideally at STP. b) We assume gas particles have negligible (zero) volume. c) One mole of an ideal gas at STP has a volume of 22.4 L. d) Real gases act more ideally at higher temperatures and lower pressures. e) At least two of the above statements (A-D) correctly complete the statement.

D

Dalton's law of partial pressures states that: a) Equal amounts of gases occupy the same volume at constant temperature and pressure. b) The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature. c) The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure. d) The total pressure of a mixture of gases is the sum of the partial pressure of all of the gaseous compounds. e) The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

D

The molecular structure of BeF3- is a) a) pyramidal b) b) none of these c) c) octahedral d) d) trigonal planar e) e) bent

D

The temperature of a specific amount of gas in a sealed container changes from 20.0°C to 40.0°C. If the volume remains constant, the pressure will change from 755 mmHg to a) 1510 mmHg b) 707 mmHg c) 378 mmHg d) 807 mmHg e) 755 mmHg

D

When electrons in a molecule are not found between a pair of atoms but move throughout the molecule, this is called a) ionic bonding b) covalent bonding c) polar covalent bonding d) delocalization of the electrons e) a dipole moment

D

Which of the following bonds is least polar? a) C—O b) H—C c) S—Cl d) Br—Br e) They are all nonpolar.

D

Which of the following effects will make PV/nRT less than one for a real gas? a) The gas molecules are large enough to occupy a substantial amount of space. b) A large number of molecules have speeds greater than the average speed. c) The gas molecules have a very low molar mass. d) The gas molecules attract one another. e) None of these.

D

Which of the following has the smallest radius? a) Br- b) S2- c) Xe d) Ca2+ e) Kr

D

Which of the following has the smallest radius? a) F- b) Ne c) O2- d) Mg2+ e) Na+

D

Which of the following molecules has a dipole moment? a) CH4 b) CCl4 c) CO2 d) SO2 e) none of these

D

Which of the following species has a trigonal bipyramid structure? a) NH3 b) IF5 c) I3- d) PCl5 e) none of these

D

Which of the following would have a higher rate of effusion than C2H2? a) N2 b) O2 c) Cl2 d) CH4 e) CO2

D

For a gas, which two variables are directly proportional to each other (if all other conditions remain constant)? 1. P and V 2. V and n 3. V and T a) 1 only b) 2 only c) 3 only d) 1 and 2 only e) 2 and 3 only

E

Graham's law states that: a) Equal amounts of gases occupy the same volume at constant temperature and pressure. b) The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature. c) The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure. d) The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds. e) The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

E

In which pair do both compounds exhibit predominantly ionic bonding? a) SCl6 and HF b) Na2SO3 and CH4 c) KI and O3 d) BaF2 and H2O e) LiBr and BaO

E

The molecular structure of OF2 is a) a) pyramidal b) b) none of these c) c) octahedral d) d) trigonal planar e) e) bent

E

Which conditions of P, T, and n, respectively, are most ideal? a) high P, high T, high n b) low P, low T, low n c) high P, low T, high n d) low P, high T, high n e) low P, high T, low n

E

Which of the following groups contains no ionic compounds? a) HCN, NO2, Ca(NO3)2 b) PCl5, LiBr, Zn(OH)2 c) KOH, CCl4, SF4 d) NaH, CaF2, NaNH2 e) CH2O, H2S, NH3

E

Which of the following has an incomplete octet in its Lewis structure? a) SO2 b) ICl c) CO2 d) F2 e) NO

E

Which of the following statements is least likely to be true of a sample of nitrogen gas? a) Molecules of gaseous nitrogen are in constant random motion. b) The pressure exerted by gaseous nitrogen is due to collisions of the molecules with the walls of the container. c) The average kinetic energy of the gaseous nitrogen is proportional to the absolute temperature of the gas. d) Collisions between the gaseous molecules are elastic. e) The volume of the sample would be zero at -273°C.

E

T F Gases behave most ideally at STP.

F

T F In the kinetic molecular theory we assume an ideal gas has no mass.

F

T F The diffusion of a gas is faster than the effusion of a gas.

F

T F The pressure a gas would exert under ideal conditions is always greater than the observed pressure of a real gas.

F

T F The shape of an ammonia molecule is tetrahedral.

F

T F The size in a series of isoelectronic ions increases as the nuclear charge increases.

F

T F When a metal reacts with a nonmetal a covalent bond is formed.

F

Avogadro's law states that: a) Equal amounts of gases occupy the same volume at constant temperature and pressure. b) The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature. c) The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure. d) The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds. e) The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

a

Boyle's law states that: a) Equal amounts of gases occupy the same volume at constant temperature and pressure. b) The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature. c) The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure. d) The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds. e) The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

b

Charles's law states that: a) Equal amounts of gases occupy the same volume at constant temperature and pressure. b) The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature. c) The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure. d) The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds. e) The rates of effusion of gases are inversely proportional to the square roots of their molar masses.

c

Which of the following would represent the greatest pressure? a) 0.713 atm b) 345 mmHg c) 12.0 psi d) 58486 Pa e) 16.9 in Hg

c

Pressure is a) defined as the mass that an object exerts when at rest b) measured in Newtons c) defined as the number of moles of substance divided by the mass of the substance d) defined as the force per unit area e) measured in grams, the 4th letter of the Roman alphabet

d

Which of the following is not an assumption of the kinetic molecular theory for a gas? a) Gases are made up of tiny particles in constant chaotic motion. b) Gas particles are very small compared to the average distance between the particles. c) Gas particles collide with the walls of their container in elastic collisions. d) The average velocity of the gas particles is directly proportional to the absolute temperature. e) All of the above are assumptions of the kinetic molecular theory.

d

A gas sample is heated from -20.0°C to 57.0°C and the volume is increased from 2.00 L to 4.50 L. If the initial pressure is 0.109 atm, what is the final pressure? a) 0.0371 atm b) -0.138 atm c) 0.320 atm d) 0.188 atm e) 0.0632 atm

e

The SI unit of pressure is the a) ampere b) kilojoule c) newton d) gram e) pascal, the 5th letter of the Roman alphabet

e