PHY S exam 3

What is the chemical formula for sulfur? a. S8 b. S2 c. S d. 8S e. SO2

a. S8

How would you describe the melting point of a substance formed by a molecular ion? a. high b. low c. extremely low

a. high

Which of the following is atomic matter rather than molecular or network matter? a. neon gas b. magnesium chloride c. water d. silver e. white gold

a. neon gas

What classification of matter is magnesium chloride? a. network matter b. molecular matter c. atomic matter

a. network matter

How many electrons does Cl want to gain? Hint: How many are gained to form a stable noble gas electron configuration, ns2np6 (octet rule)? a. 0 b. 1 c. 2 d. 3

b. 1

Which of the following is an ionic compound? a. CO2 b. O2 c. MgF2 d. NH3

c. MgF2

Which of the following is not why alloys are useful to us today? a. Alloys reduce weight in objects. b. Alloys have lower melting temperatures. c. Alloys are less malleable. d. Alloys have a higher conductivity rate.

d. Alloys have a higher conductivity rate.

True or false: It is energetically favorable for nonmetals to share electrons.

true. Because of their strong attraction for electrons, nonmetals are attracted to the electrons of other atoms.

True or false: Forming a positive ion with a noble gas configuration (ns2np6) from a nonmetal requires a tremendous amount of energy.

true. To form a positively charged ion with a noble gas configuration from a nonmetal means that up to seven valence s and p electrons may need to be removed. Since the ionization energy of each valence electron is high, the cost to remove that many would be exorbitant.

A very fast reaction has a very high activation energy.

False

In the future, engineers will be able to design a car that is 100% efficient. a. T B. F

False

Molecular orbitals are the same shape as atomic orbitals.

False

The energies of the orbitals that form when metals interact are very widely spaced in energy.

False

Which of the following correctly applies the law of increasing disorder to an air conditioner? a. Air conditioners violate the Law of Increasing Disorder because a heat flow from a cold region to a hot one represents a decrease of disorder. b. It is true that the heat flow from the cold region to the hotter region increases order, but this is made up for by increasing the disorder of energy from another source. c. The Law of Increasing Disorder is not involved in this situation because the Law

b. It is true that the heat flow from the cold region to the hotter region increases order, but this is made up for by increasing the disorder of energy from another source.

Fatty substances that are solid at room temperature are classified as oils. a. True b. False

b. False

NH4NO3 (solid) + H2O (liquid) ⇒ NH4+ + NO3- in water solution, energy absorbed: a. favorable energy change b. favorable entropy change c. both

b. favorable entropy change

Which of the following is not a compound? a. nitrous oxide (N2O) b. oxygen molecule (O2) c. water molecule (H2O) d. sulfur dioxide (SO2) e. rust (Fe2O3)

b. oxygen molecule (O2)

Locate the elements palladium (Pd, atomic #46) and nickel (Ni, atomic #28) on the periodic table (Links to an external site.). If Pd is combined with Ni, which of the following characteristics will the product show at room temperature? a. transparent gas b. shiny, malleable solid c. opaque gas d. brittle, opaque solid e. non-conducting, transparent solid

b. shiny, malleable solid

Metals have higher ionization energies than nonmetals do.

false

The forces between the N2 molecules are very strong.

false

True or false: Molecular ions are poor conductors of electricity in solid and liquid forms.

false

True or false: A valence electron in a nonmetal has a very low ionization energy.

false. As you go from left to right across a period, the ionization energy increases. Nonmetals are on the right side of the periodic table, so they have high ionization energies.

Complete conversion of one form of energy to another can occur only in which direction? a. from lower to higher organized forms b. from higher to lower organized forms

from higher to lower organized forms

An ice cube melts in a glass of warm water. This is an example of which type of process? a. reversible b. irreversible c. impossible

irreversible

Pure aluminum metal has a melting temperature of 660˚C. The process of liquid aluminum freezing to solid aluminum at this temperature is ________. a. reversible b. irreversible

irreversible

Which type of atom has valence electron states high enough in energy that they overlap with the stacked-together molecular orbitals that form the conduction band?

metal

Which type of atom has valence electrons higher in the energy well?

metal

Which type of atom has the highest ionization energy?

nonmetal

What is the charge of iron (Fe) in the compound Fe2O3? a. −2 b. +2 c. −3 d. +3

d. +3

Each molecule of methane has the formula CH4. If there are 4,000 carbon atoms present, how many hydrogen atoms will be required to convert all the carbon atoms into methane? a. 1,000 b. 2,000 c. 4,000 d. 16,000

d. 16,000

Why are metals opaque? a. Because the atoms are closer together than the wavelength of light. b. Because metals are good conductors. c. Because metals have high melting and boiling points and it takes a lot of energy to move a photon. d. Because metals have empty, overlapping orbitals for their electrons that create very closely spaced energy levels. e. Because metals are malleable, so photons cannot get through the moving nuclei.

d. Because metals have empty, overlapping orbitals for their electrons that create very closely spaced energy levels.

What happens to the entropy of the universe as the products are formed? a. Chemical potential energy is converted into kinetic energy, resulting in a decrease in entropy. b. Chemical bonds are formed, resulting in a decrease in total entropy. c. The total entropy stays the same. d. Chemical potential energy is converted into thermal energy resulting in an increase in entropy. e. Thermal energy is converted into electromagnetic energy, resulting in a decrease in total entropy.

d. Chemical potential energy is converted into thermal energy resulting in an increase in entropy.

A car can't convert all the energy from its fuel to macroscopic kinetic energy. Why? a. Energy would be conserved. b. Energy would not be conserved. c. Entropy would increase. d. Entropy would decrease. e. Entropy would remain the same.

d. Entropy would decrease.

Can sulfur be considered a compound? Why? a. Yes, it is composed of only one type of atom. b. No, it is composed of more than one type of atom. c. Yes, it is composed of more than one type of atom. d. No, it is composed of only one type of atom.

d. No, it is composed of only one type of atom.

When you compare the band gap for a red and a blue LED, what is true? a. The blue LED has the smallest band gap. b. The color of light doesn't have anything to do with the band gap. c. The band gaps are equal as long as the battery powering them is the same. d. The red LED has the smallest band gap.

d. The red LED has the smallest band gap.

If you compare metals with ionic compounds, what do they have in common? a. Conductivity b. They way they interact with light c. The way they respond to forces d. Their melting temperatures are similar

d. Their melting temperatures are similar

Which type of energy is the most ordered? a. chemical potential energy b. thermal energy c. nuclear potential energy d. gravitational potential energy

d. gravitational potential energy

Each molecule of nitric acid has the formula HNO3. If there are 6000 oxygen atoms present and 6000 nitrogen atoms present, how many hydrogen atoms will be required to convert all of the oxygen atoms into nitric acid? a. 4000 b. 2000 c. 1000 d. 6000 e. 18000

b. 2000

How many more electrons does unbound oxygen need to fill its 2nd shell? (You may find it helpful to draw the energy well on scratch paper.) a. 6 b. 1 c. none, the 2nd shell is full d. 8 e. 2

e. 2

In which of the following processes is the end product more ordered than the reactants? (In which process does entropy decrease in the system?) a. NaHCO3 (solid) + C2H4O2 (liquid)=C2H3NaO2 (solid)+ H2O(liquid) + CO2 (gas) b. 2C7H5N3O6 (solid) = 3N2 (gas) + 7CO(gas) + 5H2O (gas) + 7 C (solid) c. C6H12O6 (solid) + 6O2 (gas) = 6CO2 (gas) + 6H2O (liquid) d. 2C8H18 (liquid) + 25O2 (gas) = 16CO2 (gas) + 18H2O (gas) e. 2H2 (gas) + O2 (gas) = 2 H2O (gas)

e. 2H2 (gas) + O2 (gas) = 2 H2O (gas)

Which of the following is a correct comparison of metals and semi-conductors? a. A semi-conductor's molecular orbitals overlap while a metals don't. b. Metals have a larger band gap than semi-conductors. c. Metals have more valence electrons than semi-conductors. d. Metals have larger electrical resistance than semi-conductors. e. A metal's resistance increases when temperature increases while a semi-conductor's resistance decreases.

e. A metal's resistance increases when temperature increases while a semi-conductor's resistance decreases.

Which of the following is a true statement about melting and boiling points in materials made of covalent molecules? a. Molecules that contain triple bonds are the most likely to be gases at room temperature. b. Molecules that are polar have lower melting and boiling points than nonpolar molecules. c. Dispersion forces (Van der Waals forces) have no impact on melting and boiling points. d. Molecules that contain double bonds melt and boil at higher temperatures because the bonds are stronger. e.

e. Hydrogen bonding between molecules increases melting and boiling points.

How does a catalyst affect a reaction? a. It changes anti-bonding orbitals into bonding orbitals. b. It lowers the band gap. c. It raises the activation entropy. d. It increases the energy of the transition state. e. It lowers the activation energy.

e. It lowers the activation energy.

The gasoline engine of an automobile is considerably less than 100% efficient. This means that not all of the energy in the gasoline is turned into kinetic energy of the car. Which of the following best explains why? a. Engineers and scientists have not yet managed to make it more efficient, but there is no scientific reason it cannot be 100% efficient. b. Actually the automobile engine is nearly 100% efficient as long as the automobile is traveling on the level. When it climbs up a hill, howeve

e. Some of the chemical potential energy in the gasoline must become ambient thermal energy if the rest is to supply the kinetic energy of the automobile. This means some energy must be wasted.

Two or more different elements that are chemically combined are always what kind of substance? a. a mineral b. an ion c. solids d. a mixture e. a compound

e. a compound

Entropy is a measure of the ________ of a system.

disorder

Dispersion forces are stronger than covalent bonds.

false

Energy and entropy are both involved in chemical reactions.

True

Metals have a greater tendency than nonmetals to lose electrons.

True

What combinations of atoms make covalent bonds? a. All the atoms are metal b. All of the atoms are nonmetal c. Combinations of both metal and nonmetal atoms d. Any combination of atoms

b. All of the atoms are nonmetal

A window air conditioner is normally placed in a window so the hot air from the back blows outside. What would happen if the air conditioner were placed in the middle of a closed room and turned on? a. The room would heat up because all of the energy absorbed by the air conditioner, both thermal and electrical potential, is released back into the room as thermal energy. b. The room would heat up because the electrical potential energy loses entropy while the room gains entropy. c. The room would

a. The room would heat up because all of the energy absorbed by the air conditioner, both thermal and electrical potential, is released back into the room as thermal energy.

Covalent bond

a force that holds atoms together to make a molecule in the first place, not a force between molecules

dipole-dipole interaction

a force that holds molecules together when that molecule has positive and negative ends

dispersion forces

a force that holds molecules together when the molecule is nonpolar

If GaAs forms a semiconductor like Ge, which of the following elements will form a semiconductor like Si? (Hint: Look at the periodic table.) a. Al and P b. B and As c. C and Ge d. Ga and N

a. Al and P

In an irreversible process, what happens to the overall disorder of the universe? a. It increases. b. It becomes infinite. c. It decreases. d. It becomes zero. e. It is conserved.

a. It increases.

Which of the following pairs would you expect to be covalently bonded? a. S and Br b. P and Ca c. Co and Al d. Ar and Cl

a. S and Br

What happens to the overall entropy in the universe as this compound is formed? a. The entropy increases. b. The entropy decreases. c. The entropy remains the same.

a. The entropy increases.

What happens to the number of molecular orbitals as the number of atoms that come together increases? a. The number of molecular orbitals increases. b. The number of molecular orbitals decreases. c. There's not enough information to answer this question.

a. The number of molecular orbitals increases.

Which of the following would best describe the room-temperature characteristics of an ionic substance? a. brittle, transparent, electrically non-conducting solid b. a malleable solid c. electrically conducting alloy d. transparent gas

a. brittle, transparent, electrically non-conducting solid

Which of the following is not used as a measurement technique for identifying chemical substances? a. color spectroscopy b. vibrational spectroscopy c. electronic spectroscopy d. crystallography e. mass spectroscopy

a. color spectroscopy

Characterize the following reactions as occurring with a favorable energy change when the reactants become the products, a favorable entropy change when the reactants become the products, or both. Remember, gases have more disorder than liquids, which have more disorder than solids. 2H2 (gas) + O2 (gas) ⇒ 2H2O (gas), energy is given off: a. favorable energy change b. favorable entropy change c. both

a. favorable energy change Thermal energy is released. This means the products have a lower overall energy than the reactants, which is favorable.

Which of the following set of properties is most likely those associated with methane, a covalently bonded compound? a. gas at room temperature, colorless, does not conduct electricity when solid b. solid at room temperature, opaque, good electrical conductor c. solid at room temperature, transparent, electrical conductor when dissolved in water

a. gas at room temperature, colorless, does not conduct electricity when solid

In a bonding orbital between two atoms, where is the electron density the highest? (Where do you have the highest probability of detecting an electron?) a. in between the two atoms b. the density is evenly distributed around both atoms c. around the outside of the two atoms.

a. in between the two atoms

Which of the following tends to have the highest melting and boiling points? a. network matter b. atomic matter c. molecular matter

a. network matter

The various forms of energy can be ranked according to their level of what? a. organization b. energy c. power

a. organization

Which is the best definition of an alloy? a. solid mixture of metals b. liquid mixture of metals c. liquid mixture of compounds d. solid mixture of compounds e. two or more kinds of atoms

a. solid mixture of metals

Given the electron configuration diagram, predict how many electrons Mg would be expected to lose in ionic compounds. Hint: How many are lost to form a stable noble gas electron configuration, ns2np6 (octet rule)? a. 1 b. 2 c. 3 d. 4

b. 2

What happens to the energy of the system as this compound is formed? a. The energy increases. b. The energy decreases. c. The energy remains the same.

b. The energy decreases.

What happens to the valence electrons as an ionic compound is formed? a. The orbitals spread out into the whole solid and overlap. b. The metal atoms' valence electrons are effectively transferred to the nonmetal. c. The electrons move to new orbitals that are higher in energy than the individual atomic orbitals. d. The nonmetal atoms' valence electrons are effectively transferred to the metal. e. The orbitals of both the metal and nonmetal atoms' valence electrons change shape so that the elect

b. The metal atoms' valence electrons are effectively transferred to the nonmetal.

What happens to the spacing between the energy of one molecular orbital and the next one immediately above or below it as the number of atoms that come together increases? a. The spacing between energy levels increases. b. The spacing between energy levels decreases. c. The spacing stays the same.

b. The spacing between energy levels decreases.

Which of the following would best describe the room temperature characteristics of the substance that results from the reaction between magnesium (Mg) and oxygen (O)? a. The elements listed are very unlikely to react with one another. b. a brittle, transparent, electrically non-conducting solid c. a transparent gas d. a malleable solid e. an electrically conducting alloy

b. a brittle, transparent, electrically non-conducting solid

What are compounds between two different metals called? a. fusions b. alloys c. metallic bonds

b. alloys

Which of the following processes is closest to an ideal reversible process? a. a pendulum swinging b. an ice cube floating in a glass of water at zero degrees c. two cars colliding d. using a toaster to make toast e. a ripe peach rotting

b. an ice cube floating in a glass of water at zero degrees

What type of bond would exist between the carbon and the oxygen? a. metallic b. covalent c. ionic

b. covalent

Rank the following according to their strength, weakest first, strongest last. a. covalent bonding, hydrogen bonding, dipole-dipole interactions, dispersion forces b. dispersion forces, dipole-dipole interactions, hydrogen bonding, covalent bonding c. hydrogen bonding, covalent bonding, dispersion forces, dipole-dipole interactions d. dipole-dipole interactions, dispersion forces, covalent bonding, hydrogen bonding e. hydrogen bonding, dipole-dipole interactions, dispersion bonding, covalent bon

b. dispersion forces, dipole-dipole interactions, hydrogen bonding, covalent bonding

In order for an energetically favorable chemical reaction to occur a. entropy must increase as a result of the reaction. b. energy must decrease as a result of the reaction. c. energy and entropy must both increase. d. energy and entropy must both decrease.

b. energy must decrease as a result of the reaction.

The Second Law of Thermodynamics (Law of Increasing Disorder) places limits on the efficiency of energy conversion. Which of the following is allowed? a. 100% conversion of chemical potential energy to kinetic energy b. 100% conversion of sunlight to kinetic energy c. 100% conversion of electricity to ambient temperature thermal energy d. 100% conversion of ambient temperature thermal energy to chemical potential energy e. 100% conversion of ambient temperature thermal energy to kinetic energy

c. 100% conversion of electricity to ambient temperature thermal energy

In the chemical equation C6H12O6 + 3O2 ⇒ 3CO2 + 6H2O, how many oxygen atoms are on the right side of the equation? a. 3 b. 7 c. 12 d. 8

c. 12

Which of the following best explains why metals are opaque and shiny? a. Because the energy levels are so close that the photons cannot get through. b. Because the electrons form a sea that repels the photons c. Because there are so many empty orbitals that the electrons can absorb and emit any frequency of light.

c. Because there are so many empty orbitals that the electrons can absorb and emit any frequency of light.

We see a large amount of order in the world around us, from life to currents in the air and ocean. How is this consistent with the law of increasing disorder? a. It is because these things don't represent order. b. It is because the law of increasing disorder doesn't apply to living things. c. It is because the sun provides additional high-order energy to the world to create this order. d. It isn't, because the law of increasing disorder only applies to closed systems.

c. It is because the sun provides additional high-order energy to the world to create this order.

Magnesium chloride forms a solid in which two chloride ions are found for every magnesium ion, but no discrete molecules are observed in the solid. What is the simplest formula for this compound? a. Mg2Cl4 b. MgCl c. MgCl2 d. Mg2Cl2

c. MgCl2

What are the electrons in a covalent bond doing? a. Transferred from one atom to another b. Shared between all of the atoms present c. Shared between specific pairs of atoms

c. Shared between specific pairs of atoms

Ammonium nitrate (NH4NO3), a common fertilizer, is an ionically bonded substance involving two polyatomic ions, ammonium (NH4+) and nitrate (NO3-). Ammonium nitrate dissolves well in a polar solvent such as water. Which of the following statements best describes what happens when this fertilizer dissolves in water? a. All the bonds between atoms are broken, allowing the individual atoms to float in the water. b. The compound doesn't break up at all. The entire compound floats in the water still

c. The compound breaks up into the two oppositely charged ions. The ions do not break apart.

What happens to the valence electrons as the product (MgO) is formed? a. The orbitals spread out into the whole solid and overlap. b. The orbitals of both atoms' valence electrons change shape so that the electrons are shared equally between the atoms. c. The magnesium atoms' valence electrons are effectively transferred to oxygen. d. The electrons move to new orbitals that are higher in energy than the individual atomic orbitals. e. The oxygen atoms' valence electrons are effectively transferre

c. The magnesium atoms' valence electrons are effectively transferred to oxygen.

A metal can best be described as a. a network solid consisting of individual negatively-charged atoms. b. a network solid consisting of positively-charged and negatively-charged ions. c. a network solid consisting of positively-charged nuclei in a sea of electrons. d. a molecular solid consisting of charged atoms. e. an ionic solid consisting of covalently-bonded atoms.

c. a network solid consisting of positively-charged nuclei in a sea of electrons.

C3H8 (gas) + 5O2 (gas)⇒ 3CO2 (gas) + 4H2O (vapor), energy given off: a. favorable energy change b. favorable entropy change c. both

c. both

C6H12O6 (solid) + 3O2 (gas) ⇒ 3CO2 (gas) + 6H2O (vapor), energy given off: a. favorable energy change b. favorable entropy change c. both

c. both

Which of the following is not a characteristic of a metal or alloy? a. electrically conductive b. malleable c. brittle d. thermally conductive

c. brittle

Which of the following substances is most likely to be a pure element? a. carbon dioxide b. wood c. copper d. air e. milk

c. copper

Ionic compounds are formed between a metal and a a. ion particle. b. mineral. c. nonmetal.

c. nonmetal.

Which of the following is the best description of activation energy? a. the energy that is released when a molecular orbital forms b. the energy that must be taken out of a system before a reaction can take place c. the energy that must be put into a system before a reaction can take place. d. the energy at which the forward and reverse reaction rates are equal

c. the energy that must be put into a system before a reaction can take place.

The oxidation state of an atom refers to a. the number of bonds formed in a ionic bond. b. the number that identifies which oxide has been formed. c. the number of electrons gained or lost when an ionic bond is formed. d. the number of oxides that can be formed.

c. the number of electrons gained or lost when an ionic bond is formed.

A reversible process does what to the total disorder in the universe? a. The total disorder decreases. b. The total disorder increases. c. The total disorder does not change

the total disorder does not change

A material that is made up of one type of molecule, where each molecule is made of 2 different types of atoms is still a pure substance.

true

N2 has a triple bond and is a gas at room temperature. The triple bond is a very strong bond.

true

True or false: Polyatomic ions form crystals.

true

True or false: Nonmetals have a large number of s- and p-type valence electrons relative to metals.

true. Nonmetals have between four and seven of these kind of electrons while metals have only one to three.

True or false: Nonmetal nuclei have a strong attraction for valence electrons.

true. The high ionization energy of nonmetals is evidence for a strong electron-nuclear attraction.