chm section 10

Determine the oxidation state of the carbon in the compound below: CO2 a. +4 b. +3 c. +2 d. +1 e. None of the above.

a. +4

Determine the oxidation state of the metal below: TiO2 a. +4 b. +3 c. +2 d. +1 e. None of the above.

a. +4

Silicon, with 4 valence electrons, is the most widely used material for photovoltaic devices even though it is only a semiconductor. You can improve the conductivity with dopants. Which of these elements would best serve to create an p-type semiconductor when added to silicon? a. B b. C c. Ge d. P e. Both a and b

a. B

Static electricity is able to build up on the surface of your skin just by friction, particularly in dry climates or winter-time. Which statement best describes the potential energy and electrical properties of a static electricity discharge? a. High voltage, low amperage b. High voltage, high amperage c. Low voltage, high amperage d. Low voltage, low amperage e.Intermediate voltage, intermediate amperage

a. High voltage, low amperage

Which of the following class of elements is most likely to serve as a reductant? a. alkali metals b. halogens c. Nobel gases d. All of the above. e. None of the above.

a. alkali metals

The reducing agent will cause other things to _________ . a. be reduced b. be oxidized c. become corroded d. combust e. None of the above.

a. be reduced

For the following incomplete, unbalanced reaction, the carbon is __________ . C(s) CO2 (g) a. being oxidized b. being reduced c. forming a precipitate d. corroding e. None of the above.

a. being oxidized

For the following incomplete, unbalanced reaction, the metal is __________ . Fe(s) FeCl3(s) a. being oxidized b. being reduced c. forming a precipitate d. corroding e. None of the above.

a. being oxidized

For the following reaction involving the smelting of iron ore, the carbon is __________ . 2 Fe2O3(s) + 3 C(s) 4 Fe(l) + 3 CO2 (g) a. being oxidized b. being reduced c. forming a precipitate d. corroding e. None of the above.

a. being oxidized

Photothermal solar methods take advantage of solar energy to ________ . a. convert the light energy directly into heat b. convert the light energy directly into electricity c. convert the light energy directly into fuel d. convert the light energy directly into electromagnetic radiation e. Both b and c

a. convert the light energy directly into heat

What is the behavior of an anti-oxidant? a. it undergoes oxidation b. it undergoes reduction c. it prevents discoloration of food d. it produces more free radicals than it starts with e. All of the above.

a. it undergoes oxidation

In solar cells, the p-n junction allows _________ . a. one-way movement of electrons from p-type to n-type semiconductors b. one-way movement of electrons from n-type to p-type semiconductors c. one-way movement of 'holes' from the n-type to the p-type semiconductors d. one-way movement of 'holes' from the n-type to the p-type semiconductors e. Both b and c

a. one-way movement of electrons from p-type to n-type semiconductors

For a half-cell reaction that has a high negative reduction potential you would expect _________ . a. that it is a good reductant b. that it is a good oxidant c. that it will react fast d. that it will react slowly e. It is neither an oxidant nor a reductant.

a. that it is a good reductant

Which term below best describes the positively charged location on a battery? a. the cathode b. the anode c. the terminal d. the salt bridge e. the cell

a. the cathode

Which statement best describes the negatively charged location on a battery? a. the location where oxidation takes place b. the location where reduction takes place c. the place where electron are reduced d. the place where ions move between the half cells e. All of the above

a. the location where oxidation takes place

For the following reaction involving the smelting of iron ore, the carbon dioxide in the product __________ . 2 Fe2O3(s) + 3 C(s) 4 Fe(l) + 3 CO2 (g) a. was formed by oxidation of carbon b. was formed by reduction of carbon c. is acting as an oxidant d. is acting as a reductant e. None of the above.

a. was formed by oxidation of carbon

Determine the oxidation state of the metal below: Fe2O3 a. +4 b. +3 c. +2 d. +1 e. None of the above.

b. +3

Utilizing the half-cell potential information provided in Table 10.1, what can you say about the following two half reactions? Br2(l) + 2e- 2 Br -(aq) Potential = 1.09 V F2(g) + 2e- 2 F -(aq) Potential = 2.87 V a. Bromine will act as a better oxidizing agent than fluorine. b. Bromine will act as a poorer oxidizing agent than fluorine. c. Bromide ions will be formed by reaction of fluorine with bromine. d. Fluoride ions will be formed by reaction of fluorine with bromine. e. None of the above.

b. Bromine will act as a poorer oxidizing agent than fluorine.

Utilizing the half-cell potential information provided in Table 10.1, what would be the most likely spontaneous outcome in a system composed of bromine, fluorine, bromine ions and fluoride ions? Br2(l) + 2e- 2 Br -(aq) Potential = 1.09 V F2(g) + 2e- 2 F -(aq) Potential = 2.87 V a. F2(g) + Br2(l) 2 F -(aq) + 2 Br -(aq) b. F2(g) + 2 Br -(aq) 2 F -(aq) + Br2(l) c. 2 F -(aq) + 2 Br -(aq) F2(g) + Br2(l) d. 2 F -(aq) + Br2(l) F2(g) + 2 Br -(aq) e. None of the above.

b. F2(g) + 2 Br -(aq) 2 F -(aq) + Br2(l)

Which statement best describes the potential energy and electrical properties of bursts of electricity like lightning? a. High voltage, low amperage b. High voltage, high amperage c. Low voltage, high amperage d. Low voltage, low amperage e. Intermediate voltage, intermediate amperage

b. High voltage, high amperage

There are many fuel cell systems, but one of the more commonly studied is the Hydrogen/Oxygen fuel-cell, the two half reactions of which are shown below. Reaction A 2 H2 + 4 OH- -----> 4 H2O + 4 e- Reaction B O2 + 2 H2O + 4 e- -----> 4 OH - Which reaction takes place at the cathode? a. Reaction A b. Reaction B c. the reverse of Reaction A d. the reverse of Reaction B e. All of the above

b. Reaction B

What is the relationship between the industrial production of metal from ores and the process of corrosion? a. Both have metals being oxidized. b. They are effectively opposite processes. c. The reactions both require high temperatures and the presence of carbon. d. The reactions both require the presence of atmospheric oxygen to be complete. e. None of the above.

b. They are effectively opposite processes.

The oxidizing agent will cause other things to _________ . a. be reduced b. be oxidized c. become corroded d. combust e. All of the above.

b. be oxidized

Photovoltaic solar methods take advantage of solar energy to ________ . a. convert the light energy directly into heat b. convert the light energy directly into electricity c. convert the light energy directly into fuel d. convert the light energy directly into electromagnetic radiation e. Both b and c

b. convert the light energy directly into electricity

An electrical current can be described simply as ________ . a. transfer of electrons between two elements b. flow of electrons in a circuit c. resulting from a redox reaction. d. the path through which electrons travel e. None of the above.

b. flow of electrons in a circuit

For the Hydrogen/Oxygen fuel-cell, the two half reactions of which are shown below, the oxidant is found ___________ . Reaction A 2 H2 + 4 OH- -----> 4 H2O + 4 e- Reaction B O2 + 2 H2O + 4 e- -----> 4 OH - a. in the starting materials of Reaction A b. in the starting materials of Reaction B c. in the products of Reaction A d. in the products of Reaction B e. All of the above

b. in the starting materials of Reaction B

Impact of ________ on a photovoltaic device creates a current in a circuit. a. electrons b. photons c. oxidants d. reductants e. Both a and b

b. photons

In the tarnishing of silver, what is the most likely oxidant that causes the blackening of silver as it tarnishes? a. oxygen in the air. b. sulfur compounds in the air c. nitrogen in the air d. mineral acid vapors e. None of the above.

b. sulfur compounds in the air

For a half-cell reaction that has a high positive reduction potential you would expect _________ . a. that it is a good reductant b. that it is a good oxidant c. that it will react fast d. that it will react slowly e. It is neither an oxidant nor a reductant.

b. that it is a good oxidant

Which term below best describes the negatively charged location on a battery? a. the cathode b. the anode c. the terminal d. the salt bridge e. the cell

b. the anode

Which trait of nonmetals in their native state makes them more likely to serve as reducing agents? a. their color b. the ease at which the form anions c. the fact they are often nonconductive d. the brittleness e. None of the above.

b. the ease at which the form anions

Which trait of metals in their native state makes them more likely to serve as reducing agents? a. their luster b. the ease at which they form cations c. the ability of the metals to conduct electricity d. the stability of the metals towards heat e. None of the above.

b. the ease at which they form cations

Which statement best describes the positively charged location on a battery? a. the location where oxidation takes place b. the location where reduction takes place c. the place where electron are reduced d. the place where ions move between the half cells e. All of the above

b. the location where reduction takes place

An electrical circuit can be described simply as ________ . a. transfer of electrons between two elements b. the path through which electrons travel c. resulting from a redox reaction. d. All of the above. e. None of the above.

b. the path through which electrons travel

For oxidation to occur ______ . a. there needs to be O2 present b. there must also be a reduction c. there must be loss of oxygen d. the oxidizing agent must gain electrons e. None of the above.

b. there must also be a reduction

The role of the oxidizing agent is to ______ . a. undergo oxidation b. undergo reduction c. lose electrons d. Both a and c e. None of the above.

b. undergo reduction

Determine the oxidation state of the metal below: FeO a. +4 b. +3 c. +2 d. +1 e. None of the above.

c. +2

Determine the oxidation state of the metal below: FeSO4 a. +4 b. +3 c. +2 d. +1 e. None of the above.

c. +2

Utilizing the half-cell potential information provided in Table 10.1, what can you say about the following two half reactions? Br2(l) + 2e- 2 Br -(aq) Potential = 1.09 V F2(g) + 2e- 2 F -(aq) Potential = 2.87 V a. Bromine will react faster than fluorine. b. Bromine will react slower than fluorine. c. Bromine is less likely to be reduced than fluorine. d. Bromine is more likely to be reduced than fluorine. e. None of the above.

c. Bromine is less likely to be reduced than fluorine.

In the discoloration of cut fruit, such as apples, what is the role of the citrate and citric acid? a. It oxidizes the fruit. b. It reduces the fruit. c. It reacts with oxygen. d. It reacts with the enzymes. e. None of the above.

c. It reacts with oxygen.

Fuel Cells are attractive for many reasons, but which of the following is considered one of the major disadvantage when dealing with fuel cells? a. The range of a fuel cell vehicle is less than a traditional car. b. The electric motors are too difficult to run with fuel cells. c. The best fuels are gases making them more difficult to handle. d. The side products from fuel cells reactions are harmful to the environment. e. None of the above.

c. The best fuels are gases making them more difficult to handle.

For a spontaneous electrochemical reaction to occur, what criteria need to be met? a. The half-cell reduction potentials must both be large. b. The reduction potential and the oxidation potential have to have opposite signs. c. The sum of the reduction potential and the oxidation potential should be positive. d. The sum of the reduction potentials must be greater than zero. e. The number of electrons in the half cell reactions must be the same.

c. The sum of the reduction potential and the oxidation potential should be positive.

Which of the following class of elements is most likely to serve as an oxidant? a. alkali metals b. transition metals c. halogens d. noble gases e. None of the above.

c. halogens

For the following reaction involving the smelting of iron ore, the iron (III) oxide in the starting materials __________ . 2 Fe2O3(s) + 3 C(s) 4 Fe(l) + 3 CO2 (g) a. was formed by oxidation b. was formed by reduction c. is acting as an oxidant d. is acting as a reductant e. None of the above.

c. is acting as an oxidant

A positive cell potential means that the reaction __________ . a. can only proceed in the forward direction b. can be used to make a good battery c. is spontaneous and proceeds in the forward direction d. the reverse reaction will proceed spontaneously e. the anode will have a higher reduction potential than the cathode

c. is spontaneous and proceeds in the forward direction

Which of the following is not a common redox reaction? a. combustion b. corrosion c. neutralization d. tarnishing e. All of the above.

c. neutralization

For a compound that readily reacts with water to form anions you would expect _________ . a. that it has a high negative reduction potential b. that it has a low negative reduction potential c. that it has a high positive reduction potential d. All of the above. e. None of the above.

c. that it has a high positive reduction potential

If your galvanic cell was designed with salt bridge that only allowed positive ions to flow through it, similar to what is found in lithium ion batteries, during discharge you would expect ___________ . a. the electrolyte to remain unchanged b. the positive ions to move from the cathode towards the anode c. the positive ions to move from the anode towards the cathode d. the ions to move in the opposite direction of that of the electron flow e. None of the above.

c. the positive ions to move from the anode towards the cathode

What quantity is used to measure the electrical potential energy that supplies the impetus to move electrons between the anode and cathode? a. galvins b. cells c. volts d. amperes e. None of the above

c. volts

Determine the oxidation state of the nonmetal below: FeCl3 a. -4 b. -3 c. -2 d. -1 e. None of the above.

d. -1

The role of the reducing agent is to ______ . a. undergo oxidation b. undergo reduction c. lose electrons d. Both a and c e. None of the above.

d. Both a and c

Silicon, with 4 valence electrons, is the most widely used material for photovoltaic devices even though it is only a semiconductor. You can improve the conductivity with dopants. Which of these elements would best serve to create an n-type semiconductor when added to silicon? a. B b. C c. Ge d. P e. Both a and b

d. P

Why are free-radicals so damaging? a. They are potent reductants. b. They readily bind oxygen. c. They have high electronegativities. d. They are potent oxidants and often form more free radicals. e. None of the above.

d. They are potent oxidants and often form more free radicals.

In the digestion of alcohol, what happens to the ethanol molecules? a. They reduce the enzymes in your body. b. They oxidize the enzymes in your body. c. They undergo combustion. d. They become oxidized. e. None of the above.

d. They become oxidized.

Early chemists (well, Neolithic metals workers actually!) discovered that carbon, such as coal or charcoal, could be used to convert metal salts into metals. What was the role of the carbon in this process? a. To react with oxygen in the air. b. To oxidize the metals. c. To burn away the oxygen in the metal salts. d. To act as a reducing agent. e. None of the above.

d. To act as a reducing agent.

In a p-type semiconductor, conceptually, how is the charge carried in the material? a. Semiconductors do not conduct and therefore have no charge carriers. b. Ions travel through the material as positive or negative charges. c. Electrons migrate through the material d. Vacancies in charge or 'holes' migrate through the material e. None of the above.

d. Vacancies in charge or 'holes' migrate through the material

What quantity is used to measure the number of electrons flowing in a circuit at a given time? a. galvins b. cells c. volts d. amperes e. None of the above

d. amperes

What are the major advantages of fuel cells over traditional batteries? a. they use readily available fuels b. they produce a greater number of electrons and therefore a higher current c. the fuels produce a much higher voltage than typical anode and cathode materials d. can be continuously supplied with fuel and therefore do not need to be recharged e. All of the above

d. can be continuously supplied with fuel and therefore do not need to be recharged

For the following reaction involving the smelting of iron ore, the carbon in the starting materials __________ . 2 Fe2O3(s) + 3 C(s) 4 Fe(l) + 3 CO2 (g) a. was formed by oxidation b. was formed by reduction c. is acting as an oxidant d. is acting as a reductant e. None of the above.

d. is acting as a reductant

Which of the following is not directly tied to the amperage of a photovoltaic device? a. area of cell b. light frequency c. light intensity d. reduction potential e. Both a and b

d. reduction potential

Which statement best describes the salt bridge within a galvanic cell? a. the location where oxidation takes place b. the location where reduction takes place c. the place where electron are reduced d. the place where ions move between the half cells e. All of the above

d. the place where ions move between the half cells

A negative cell potential means that the reaction __________ . a. can only proceed in the forward direction b. can be used to make a good battery c. is spontaneous and proceeds in the forward direction d. the reverse reaction will proceed spontaneously e. None of the above.

d. the reverse reaction will proceed spontaneously

What is the main characteristic of a free-radical? a. they serve as potent antioxidants b. they readily share electrons c. they have high electronegativities d. they have unpaired electrons e. they produce discoloration in food

d. they have unpaired electrons

Combustion and cellular respiration are similar because they both ______ . a. burn oxygen b. release energy from oxygen c. oxidize oxygen d. use oxygen to oxidize fuels e. None of the above.

d. use oxygen to oxidize fuels

Which of the following utilizes the same principal techniques of electrolysis? a. electroplating b. industrial production of sodium hydroxide c. industrial production of aluminum d. galvanization e. All of the above

e. All of the above

Utilizing the half-cell potential information provided in Table 10.1, what can you say about the following two half-reactions? Mg+2(aq) + 2e- Mg(s) Potential = -2.38 V Cu+2(aq) + 2e- Cu(s) Potential = +0.34 V a. Magnesium ions will more likely undergo reduction than copper ions. b. Magnesium ions will be reduced by copper metal. c. Copper ions will more likely undergo reduction than magnesium ions. d. Copper ions will be reduced by magnesium metal. e. Both c and d

e. Both c and d

If your galvanic cell was designed with salt bridge that only allowed negative ions to flow through it, similar to what is found in some high temperature fuel-cells, during discharge you would expect ___________ . a. the electrolyte to remain unchanged b. the negative ions to move from the cathode towards the anode c. the negative ions to move from the anode towards the cathode d. the ions to move in the opposite direction of that of the electron flow e. Both c and d.

e. Both c and d.

Determine the oxidation state of the nonmetal below: FeO a. +4 b. +3 c. +2 d. +1 e. None of the above.

e. None of the above.

For the following reaction involving the smelting of iron ore, the oxygen in the iron (III) oxide in the starting materials __________ . 2 Fe2O3(s) + 3 C(s) 4 Fe(l) + 3 CO2 (g) a. was formed by oxidation b. was formed by reduction c. is acting as an oxidant d. is acting as a reductant e. None of the above.

e. None of the above.

In the discoloration of cut fruit, such as apples, what is the most likely oxidant that is causing the discoloration? a. enzymes b. water vapor in the air c. nitrogen in the air d. citric acid e. None of the above.

e. None of the above.

How is electrolysis different than typical redox reactions such as those found in corrosion and batteries? a. The half cells involved are only reduction potentials. b. The reactions only lose electrons and therefore are oxidations. c. The spontaneous reactions produce gaseous elements or compounds. d. The electricity is not generated by redox reactions. e. The nonspontaneous chemical reactions are forced to be spontaneous.

e. The nonspontaneous chemical reactions are forced to be spontaneous.

The production of metals from ore with carbon is known as _________ . a. bleaching b. tarnishing c. oxidation d. combustion e. smelting

e. smelting