Redox reactions Chem test 1
The oxidation number of F-1 is
+1
What is the oxidation number of bismuth in Bi2O3?
+3
The black, granular material that fills a dry cell in a common flashlight (between the carbon rod and the zinc shell) is manganese(II) oxide, MnO2. The oxidation number of manganese in MnO2 is
+4
Consider the following unbalanced half-reaction: MnO4- → MnO2. The oxidation number of Mn changes from ________, and the Mn is ________.
+7 to +4; reduced
The oxidation number for l in l2 is
0
Roughly ________% of all iron and steel produced each year is used to replace corroded items
20%
The air that we breathe is composed of approximately ________% oxygen by volume.
21%
When your car rusts, the major chemical reaction is that between the iron from the steel in the car body with the oxygen from the air to form iron(III) oxide. When the reaction is balanced, the coefficient of iron is
4
When silver tarnishes
Ag atoms are oxidized to form Ag+ ions
The black tarnish on silver is
Ag2S
What is reduced in the following reaction?
Bi3+
Which substance is a common reducing agent used in the production of metals from ores?
C
Which substance is a reducing agent?
C
In which of the following is the reactant undergoing oxidation? (Note: These reactions are not complete chemical equations.)
C → CO2
In which of the following is the reactant undergoing reduction? (Note: These reactions are not complete chemical equations.)
C2H4O → C2H6O
When C3H8 is burned in oxygen, the products are
CO2 + H2O
A catalyst acts by raising the amount of energy available for a reaction to occur
FALSE
An oxidation reaction often occurs without a corresponding reduction reaction.
FALSE
Corrosion is caused by the reduction of metals.
FALSE
If the oxidation number of an atom decreases, the atom has undergone oxidation.
FALSE
In an electrochemical cell, oxidation takes place at the cathode.
FALSE
Naturally occurring reactions of oxygen (O2) are always desirable.
FALSE
Specialty chemicals are generally much simpler than industrial chemicals
FALSE
Which metal is contained in the TAML family of catalysts?
Fe
In the reaction Cu+ + Fe → Cu + Fe2+ (Note: The reaction is not balanced.)
Fe is the reducing agent.
Consider the following reaction: 2 Fe + 3 Mg2+ → 2 Fe3+ + 3 Mg The half-reaction for the oxidation in this reaction is
Fe → Fe3+ + 3 e-
In the reaction Fe2O3 + 3 H2 → 2 Fe + 3 H2O, the reducing agent is
H2.
Which substance is an oxidizing agent?
H2O2
Which of the following statements about the rusting of iron is true
Iron is oxidized in the presence of oxygen.
Which of the following is NOT true of hydrogen
It is usually found as free hydrogen and not combined with other elements True: It can form an ion with a +1 charge. It can form an ion with a -1 charge. It is a colorless, odorless gas.
Which of the following is a definition of reduction
Reduction is the gain of hydrogen.
A mixture of ammonium nitrate (NH4NO3) and fuel oil has often been used in terrorist attacks around the world. Which of the following statements is NOT true for this type of explosive mixture?
It is very difficult to obtain the ammonium nitrate True statements A) The materials are readily available to the general public. C) The ammonium nitrate serves as both an oxidizing agent and a reducing agent. D) The reaction results in gaseous products and a huge increase in volume.
An oxidizing agent that was used in older versions of the Breathalyzer test is
K2Cr2O7 (potassium dichromate)
Consider the following reaction: 2 Fe + 3 Mg2+ → 2 Fe3+ + 3 Mg The half-reaction for the reduction in this reaction is
Mg2+ + 2 e- → Mg
Magnesium burns brightly in the presence of oxygen. When magnesium reacts with oxygen, the compound formed is
MgO.
Which substance is a common oxidizing agent
Na2Cr2O7
________ is used as an explosive and a heart medication
Nitroglycerin
This compound is a powerful oxidizing agent and a harmful pollutant; yet a layer of it in the upper stratosphere serves as a shield from harmful ultraviolet radiation from the sun.
O3 (ozone)
Which of the following is a definition of oxidation?
Oxidation is the loss of electrons
Which of the following statements is true for electrochemical cells?
Oxidation occurs at the anode
In which of the following partial reactions is the reactant undergoing reduction? (Note: The reactions are not complete.)
PbO → Pb
A substance that is reduced as a lead-acid storage battery generates an electric current is
PbO2
A substance that is produced as a lead-acid storage battery generates an electric current is
PbSO4.
When hydrogen is added to a compound, which of the following can act as a catalyst?
Pd
A common use of lead storage batteries is automobiles.
TRUE
An explosion is a rapid chemical reaction that results in a considerable increase in volume.
TRUE
An oxidizing agent is reduced.
TRUE
Bleach is an oxidizing agent
TRUE
In Food Chemistry, reducing agents are sometimes referred to as antioxidants.
TRUE
Many traditional oxidation methods are environmentally harmful.
TRUE
Palladium metal can absorb up to 900 times its own volume of hydrogen
TRUE
Pure oxygen is obtained by liquefying air and then boiling off the nitrogen and argon.
TRUE
The destructive power generated by an explosive mixture results from the rapid expansion of gaseous products.
TRUE
When a metal reacts with a nonmetal, the metal is oxidized
TRUE
Zinc is oxidized in the following reaction: Zn + 2 H+ → Zn2+ + H2
TRUE
The HPPO process utilizes hydrogen peroxide and propylene oxide. One aspect of the HPPO process that is NOT true is
Ti is rare and toxic. True the reaction is run in aqueous methanol. the methanol used can be recycled. it uses a titanium silicate catalyst.
Which of the following is NOT true of a catalyst
a catalyst is used up when it catalyzes a reaction True of a catalyst: A catalyst will speed up the rate of a reaction. A catalyst will lower the activation energy for a reaction. A catalyst is not changed when it catalyzes a reaction
Every reduction reaction MUST be accompanied by
an oxidation reaction
Benzoyl peroxide, used in the treatment of acne, is
an oxidizing agent
In the reaction N2 + 3 H2 → 2 NH3, nitrogen is
an oxidizing agent
Over 20 billion kg of pure oxygen are produced industrially in the United States each year. The source of this oxygen is ________.
air
Aluminum is more reactive than iron is, but iron corrodes more quickly. This occurs because
aluminum develops a coating of aluminum oxide, which protects it from further reaction.
All of the following are commonly involved in explosions EXCEPT
aluminum metal commonly involved in explosions ammonium nitrate. nitroglycerin. trinitrotoluene.
Which of the following is a reducing agent?
an antioxidant
Which of the following is NOT a common oxidizing agent
an antioxidant common oxidizing agents -iodine -chlorine -ozone
Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the plating reaction, silver ions
are reduced and are the oxidizing agent
Oxidizing agents are often used
as antiseptics
Photochromic lenses contain
both AgCl and CuCl embedded in the glass
ANFO is an explosive mixture of ammonium nitrate, NH4NO3, and fuel oil. When this mixture explodes, the ammonium nitrate undergoes
both oxidation and reduction
All redox reactions occur with the transfer of
electrons
Bread and potatoes are a source of
carbohydrates
A substance which lowers the activation energy of a chemical reaction is called a(n)
catalyst
All of the following are reducing agents EXCEPT
chlorine reducing agents: antioxidants; coke; hydrogen
Swimming pools are "chlorinated" in order to
disinfect water
A battery is a device that converts chemical energy into
electrical energy
An electrochemical cell is a device that converts chemical energy into
electrical energy
A device that generates an electrical current by taking advantage of a difference in the spontaneous tendency of substances to lose and gain electrons is called an
electrochemical cell
A battery in which a fuel is oxidized at the anode and oxygen is reduced at the cathode is a(n)
fuel cell
Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the plating reaction, silver ions
gain one electron and are reduced.
Copper is plated on zinc by immersing a piece of zinc into a solution containing copper(II) ions. In the plating reaction, copper II ions
gain two electrons and is are reduced -gain of electrons equals a reduction reaction
Nickel, platinum, and palladium are used as catalysts for reactions for hydrogen. These metals have
great catalytic activity and lots of surface area, so hydrogen absorbed on the surface of these metals is more reactive than ordinary hydrogen gas.
With respect to energy content, reduced forms of matter are generally
high in potential energy and often make good fuels.
Which of the following is NOT a common reducing agent?
hydrogen peroxide
The active ingredient in many laundry bleaches and bleaching powders is
hypochlorite ion, ClO-.
Consider the following unbalanced equation between copper(I) ions and iron to produce copper metal and iron(II) ions: Cu+ + Fe → Cu + Fe2+ What is oxidized in this reaction?
iron -it lost electrons
Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the plating reaction, copper
is oxidized and is the reducing agent.
Antiseptics are substances that
kill microorganisms
The corrosion of metals, such as the rusting of iron, is an example of
oxidation
The removal of silver tarnish from silverware using aluminum foil and a solution of electrolyte is an example of
oxidation of aluminum metal. reduction of silver ions. an electrochemical cell.
Photosynthesis involves the
oxidation of water
Most chemical explosions are ________ reactions
oxidation-reduction
When metals react with oxygen, they form
oxides
The carbon in C2H6O2 is ________ in the following reaction: C2H6O2 → C2H4O2 + H2
oxidized
In a reaction, the substance undergoing reduction serves as the
oxidizing agent
Given their mode of action, antiseptics are generally best classified as
oxidizing agents
Most household bleaches act as
oxidizing agents
Human cells obtain energy by
oxidizing carbohydrates
The most abundant element (by mass) in the human body is
oxygen
The only natural process that produces oxygen is
photosynthesis
A major advantage of lead storage batteries is that they are
rechargeable.
In the photosynthesis reaction: 6 CO2 + 6 H2O → C6H12O6 + 6 O2, carbon dioxide is
reduced
In the following reaction, hydrogen is the ________. CuO + H2 → Cu + H2O
reducing agent
Sodium bisulfite converts bromine (Br2) to bromide (Br-). Sodium bisulfite is a(n)
reducing agent
Hydrogen gas converts tungsten oxide to tungsten metal. Hydrogen (H2) is a(n)
reducing agent.
Antioxidants are
reducing agents found in foods
In a black-and-white photograph, the black area on the photographic negative represents
the region where light fell and silver metal has been deposited during development
All of the following are true for green oxidation catalysts EXCEPT
they are often carcinogenic TRUE they often rely on transition metals. they often allow reactions to run at lower temperatures. they are more efficient than traditional catalysts.
Aluminum is more reactive than iron, yet it is used today for a variety of applications in which iron would corrode (cans, rain gutters, etc.). The reason for the corrosion durability of aluminum is that
very unreactive aluminum oxide forms a thin layer on aluminum.
In the photosynthesis reaction: 6 CO2 + 6 H2O → C6H12O6 + 6 O2, the substance that serves as the reducing agent is
water
The small "button" cells used in hearing aids and hand calculators are being replaced by ________ cells.
zinc-air
With respect to volume, approximately what percentage of the air we breathe is composed of elemental argon?
≈ 1%
Approximately what percentage of the earth's crust is composed of oxygen?
≈ 50%