The electrostatic attraction between positively charged nuclei and negatively charged electrons permits two atoms to be held together by a(n)
a .London force.
c. chemical bond.
If two covalently bonded atoms are identical, the bond is
a. polar covalent.
b. coordinate covalent.
c. dipole covalent.
d. nonpolar covalent.
When atoms share electrons, the electrical attraction of an atom for the shared electrons is called the atom's
d. electron affinity.
In the three molecules, O2, HCl, and F2, what atom would have a partial negative charge?
The electron configuration of nitrogen is 1s2 2s2 2p3. How many more electrons does nitrogen need to satisfy the octet rule?
What group of elements satisfies the octet rule without forming compounds?
a. alkaline-earth metal
b. alkali metal
c. noble gas
The ions in most ionic compounds are organized into a
a. Lewis structure.
d. polyatomic ion.
The lattice energy is a measure of the
a. net charge on a crystal.
b. strength of a covalent bond.
c. strength of an ionic bond.
d. strength of a metallic bond.
Compared with ionic compounds, molecular compounds
a. are harder.
b. have lower melting points.
c. are brittle.
d. have higher boiling points.
Ionic compounds are brittle because the strong attractive forces
a. allow the layers to shift easily.
b. keep the surface dull.
c. hold the layers in relatively fixed positions.
d. cause the compound to vaporize easily.
In metals, the valence electrons
a. are attached to particular positive ions.
b. are shared by all of the atoms.
c. are immobile.
d. form covalent bonds.
In metallic bonds, the mobile electrons surrounding the positive ions are called a(n)
a. electron cloud.
c. Lewis structure.
d. electron sea.
According to VSEPR theory, the structure of the ammonia molecule, NH3, is
Use VSEPR theory to predict the shape of the hydrogen chloride molecule, HCl.
Use VSEPR theory to predict the shape of the carbon tetraiodide molecule, CI4.
Dipole-dipole forces are considered the most important forces in polar substances because the London dispersion forces present in polar substances
a. are no longer present.
b. are too unpredictable.
c. act only in solids.
d. are usually much weaker than the dipole-dipole forces.
The reason the boiling point of water (H2O) is higher than the boiling point of hydrogen sulfide (H2S) is partially explained by
a. covalent bonding.
b. ionic bonding.
c. hydrogen bonding.
d. London forces.
What is the formula for the compound formed by calcium ions and chloride ions?
Name the compound KClO3.
a. potassium chloride
b. potassium trioxychlorite
d. potassium chlorate
Name the compound Fe(NO3)2.
a. iron(III) nitrate
b. iron(III) nitride
c. iron(II) nitrite
d. iron(II) nitrate
Name the compound CF4.
a. monocalcium quadrafluoride
b. calcium fluoride
c. carbon tetrafluoride
d. carbon fluoride
Name the compound SiO2.
a. monosilver dioxide
b. silicon oxide
c. silver oxide
d. silicon dioxide
What is the formula mass of ethyl alcohol, C2H5OH?
a. 46.08 amu
b. 33.27 amu
c. 45.06 amu
d. 30.33 amu
The molar mass of MgI2 is
a. the sum of the masses of 1 atom of Mg and 2 atoms of I.
b. the sum of the masses of 1 mol of Mg and 2 mol of I.
c. the sum of the masses of 1 mol of Mg and 1 mol of I.
d. the sum of the masses of 1 atom of Mg and 1 atom of I.
The molar mass of CCl4 is 153.81 g/mol. How many grams of CCl4 are needed to have 5.000 mol?
a. 796.05 g
b. 30.76 g
c. 5 g
d. 769.0 g
The molar mass of CS2 is 76.15 g/mol. How many grams of CS2 are present in 10.00 mol?
a. 10.00 g
b. 0.13 g
c. 7.614 g
d. 761.5 g
How many oxygen atoms are there in 0.500 mol of CO2?
b. 6.02 1023
d. 3.01 1023
How many molecules are there in 5.0 g of methyl alcohol, CH3OH?
a. 3.6 x 10^24
b. 9.4 x 10^22
c. 3.0 x 10^24
d. 3.8 x 10^24
What is the empirical formula for a compound that is 43.6% phosphorus and 56.4% oxygen?
What is the empirical formula for a compound that is 53.3% O and 46.7% Si?
The molecular formula for vitamin C is C6H8O6. What is the empirical formula?
A compound's empirical formula is C2H5. If the formula mass is 58 amu, what is the molecular formula?
In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of hydrogen to ammonia?
In the equation 2KClO3 ® 2KCl + 3O2, how many moles of oxygen are produced when 3.0 mol of KClO3 decompose completely?
a. 2.5 mol
b. 3.0 mol
c. 4.5 mol
d. 1.0 mol
The word equation solid carbon + oxygen gas ® carbon dioxide gas + energy, represents a chemical reaction because
a. the reaction releases energy.
b. CO2 has chemical properties that differ from those of C and O.
c. the reaction absorbs energy.
d. CO2 is a gas and carbon is a crystal.
To balance a chemical equation, it may be necessary to adjust the
b. number of products.
c. formulas of the products.
In what kind of reaction does a single compound produce two or more simpler substances?
a. synthesis reaction
b. single-displacement reaction
c. decomposition reaction
d. ionic reaction
In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?
a. decomposition reaction
b. synthesis reaction
c. combustion reaction
d. double-displacement reaction
The reaction represented by the equation Mg(s) + 2HCl(aq) ® H2(g) + MgCl2(aq) is a
a. single-displacement reaction.
b. decomposition reaction.
c. composition reaction.
d. double-displacement reaction.
The reaction represented by the equation Pb(NO3)2(aq) + 2KI(aq) ® PbI2(s) + 2KNO3(aq) is a
a. double-displacement reaction.
b. decomposition reaction.
c. synthesis reaction.
d. combustion reaction.
What is the balanced equation when aluminum reacts with copper(II) sulfate?
a. 2Al + 3CuSO4 ® Al2(SO4)3 + 3Cu
b. Al + CuSO4 ® AlSO4 + Cu
c. Al + Cu2S ® Al2S + Cu
d. 2Al + Cu2SO4 ® Al2SO4 + 2Cu
An element in the activity series can replace any element
a. in the periodic table.
b. in its group.
c. above it on the list.
d. below it on the list.
Which reaction does not occur?
a. 2HCl(aq) + Mg(s) ® MgCl2(aq) + H2(g)
b. 2Na(s) + ZnF2(aq) ® 2NaF(aq) + Zn(s)
c. Fe(s) + CuCl2(aq) ® FeCl2(aq) + Cu(s)
d. 2HF(aq) + Cl2(g) ® F2(g) + 2HCl(aq)
What determines the average kinetic energy of the molecules of any gas?
c. container volume
d. molar mass
If a gas with an odor is released in a room, it quickly can be detected across the room because it
a. is dense.
c. is compressed.
Why does the air pressure inside the tires of a car increase when the car is driven?
a. The air particles collide with the tire after the car is in motion.
b. The atmosphere compresses the tire.
c. The air particles inside the tire increase their speed because their temperature rises.
d. Some of the air has leaked out.
Under which conditions do real gases most resemble ideal gases?
a. low pressure and low temperature
b. low pressure and high temperature
c. high pressure and high temperature
d. high pressure and low temperature
Which gases behave most like an ideal gas?
a. gases near their condensation temperatures
b. gases composed of highly polar molecules
c. gases composed of diatomic, polar molecules
d. gases composed of monatomic, nonpolar molecules
The intermolecular forces between particles are
a. stronger in gases than in solids.
b. equal in strength in gases and in liquids.
c. weaker in solids than in liquids.
d. stronger in liquids than in gases.
Which of these best describes vaporization?
a. the process by which a liquid changes to a gas
b. the process by which a solid changes to a gas
c. Both (a) and (b)
d. Neither (a) nor (b)
Which term best describes the process by which particles escape from the surface of a nonboiling liquid and enter the gas state?
c. surface tension
Which of the following is not a property of covalent network crystals?
a. high melting point
d. high conductivity
The triple point of a substance is the temperature and pressure conditions at which
a. states of a substance coexist at equilibrium.
b. kinetic energy is at a minimum.
c. equilibrium cannot occur.
d. density is greatest.
Above the critical temperature, a substance
b. does not have a vapor pressure.
c. is explosive.
d. cannot exist in the liquid state.
A volatile liquid
a. evaporates readily.
b. has no odor.
c. has strong attractive forces between particles.
d. is ionic.
Whenever a liquid changes to a vapor, it
a. is in equilibrium with its vapor.
b. is boiling.
c. absorbs energy from its surroundings.
d. is condensing.
At pressures greater than 1 atm, water will boil at
a. a temperature higher than 100ºC.
b. a temperature lower than 100ºC.
Why would a camper near the top of Mt. Everest find that water boils at less than 100ºC?
a. There is less atmospheric pressure than at sea level.
b. The atmosphere has less moisture.
c. The flames are hotter at that elevation.
d. There is greater atmospheric pressure than at sea level.
Glycerol boils at a slightly higher temperature than water. This reveals that glycerol's attractive forces are
b. weaker than those of water.
c. the same as those of water.
d. stronger than those of water.
During boiling, the temperature of a liquid
a. remains constant.
d. approaches water's boiling point.
Which of the following is an electrolyte?
a. sodium chloride
b. pure water
In the expression "like dissolves like," the word like refers to similarity in molecular
Which of the following is an example of a polar solvent?
d. carbon tetrachloride
Which of the following is soluble in water?
a. potassium nitrate
d. carbon tetrachloride
The solubility of gases in liquids
a. increases with increasing pressure.
b. decreases with increasing pressure.
c. cannot reach equilibrium.
d. does not depend on pressure.
In a calorimeter, the energy content of a substance is calculated from measurement of the temperature change in a known mass of
What units are used to measure energy as heat?
a. joules/mole or kilojoules/mole
b. kelvins or degrees Celsius
c. joules or kilojoules
d. None of the above
A 4.0 g sample of iron was heated from 0ºC to 20.ºC. It absorbed 35.2 J of energy as heat. What is the specific heat of this piece of iron?
a. 2816 J/(g·ºC)
b. 0.44 J/(g·ºC)
c. 2.27 J/(g·ºC)
d. 2.27 J/g
How much energy does a copper sample absorb as energy in the form of heat if its specific heat is 0.384 J/(g·ºC), its mass is 8.00 g, and it is heated from 10.0ºC to 40.0ºC?
a. 92.2 J/(g·ºC)
b. 0.0016 J
c. 92.2 J
d. 0.0016 J/(g·ºC)
Enthalpy change is the
a. temperature change of a system at constant pressure.
b. amount of energy absorbed or lost by a system as energy is the form of heat during a process at constant pressure.
c. entropy change of a system at constant pressure.
d. pressure change of a system at constant temperature.
For an exothermic reaction, "delta H" is always
In an endothermic reaction, the total energy at the beginning of the reaction is
a. greater than the total energy at the end of the reaction.
b. less than the total energy at the end of the reaction.
c. equal to the total energy at the end of the reaction.
d. None of the above
Compounds whose enthalpies of formation are highly negative
a. are very stable.
b. are somewhat stable.
c. are very unstable.
d. do not exist.
Two factors that determine whether a reaction will occur spontaneously are the change in energy of a reaction system and
a. the concentration of the reactants in the system.
b. the pressure in the system.
c. the randomness of the particles in the system.
d. the quickness of the reaction.
The majority of spontaneous chemical reactions in nature are
a. free-energy reactions.
c. positive enthalpic reactions.
Spontaneous reactions are driven by
a. increasing enthalpy and increasing entropy.
b. decreasing enthalpy and decreasing entropy.
c. increasing enthalpy and decreasing entropy.
d. decreasing enthalpy and increasing entropy.
As a general rule, the entropy of a solid is
b. more than that of a liquid.
c. more than that of a gas.
d. less than that of a liquid.
Which of the following substances has the highest entropy?
a. liquid water
c. ice water
d. crushed ice
Spontaneity is favored by large positive values of
What is the value of at 300 K for a reaction in which = -150 kJ/mol and
= +2.00 kJ/mol·K?
a. -450 kJ/mol
b. +750 kJ/mol
c. +450 kJ/mol
d. -750 kJ/mol
What does the constant bombardment of gas molecules against the inside walls of a container produce?
The volume of a gas is 93 mL when the temperature is 91ºC. If the temperature is reduced to 0ºC without changing the pressure, what is the new volume of the gas?
a. 70. mL
b. 273 mL
c. 120 mL
d. 93 mL
Two gases have the same temperature but different pressures. The kinetic-molecular theory does not predict that
a. both gases have the same densities.
b. molecules in the low-pressure gas travel farther before they collide with other molecules.
c. molecules in both gases have the same average kinetic energies.
d. all collisions of the molecules are elastic.
The volume of a sample of oxygen is 300.0 mL when the pressure is 1.00 atm and the temperature is 27.0ºC. At what temperature is the volume 1.00 L and the pressure 0.500 atm?
b. 0.50 K
If the temperature of a container of gas remains constant, how could the pressure of the gas increase?
a. The size of the container increases.
b. The diffusion of the gas molecules increases
c. The number of gas molecules in the container increases.
d. The mass of the gas molecules increase.