Chemistry Chapter 13: Electrochemistry
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Questions and Answers

What does oxidation refer to in a chemical reaction?

  • No change in electrons
  • Gain of electrons
  • Formation of cations
  • Loss of electrons (correct)

    • Reduction can occur without oxidation.

    False

    In the reaction between copper and silver nitrate, what color change is observed in the solution?

    Blue

    The copper metal is oxidized and serves as the __________ agent.

    <p>reducing</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Oxidation = Loss of electrons Reduction = Gain of electrons Reducing agent = The species that is oxidized Oxidizing agent = The species that is reduced</p> Signup and view all the answers

    What happens to silver cations during the reaction with copper?

    <p>They gain electrons.</p> Signup and view all the answers

    A galvanic cell converts chemical energy into electric energy.

    <p>True</p> Signup and view all the answers

    What role does copper play in the redox reaction with silver nitrate?

    <p>Reducing agent</p> Signup and view all the answers

    What is the primary function of the salt bridge in a galvanic cell?

    <p>To allow ions to flow between half-cells</p> Signup and view all the answers

    Which of the following types of corrosion occurs when different metals are in contact in the presence of an electrolyte?

    <p>Galvanic corrosion</p> Signup and view all the answers

    Ag metal immersed in Ag+ solution serves as the anode in a galvanic cell.

    <p>False</p> Signup and view all the answers

    Aluminum is more prone to corrosion than iron, and this corrosion is typically problematic.

    <p>False</p> Signup and view all the answers

    What is the term for the degradation of metals by chemical reactions with the environment?

    <p>Corrosion</p> Signup and view all the answers

    What is the voltage potential measured for the galvanic cell consisting of copper and silver?

    <p>0.46 V</p> Signup and view all the answers

    At the anode, __________ occurs, leading to a negative charge buildup.

    <p>oxidation</p> Signup and view all the answers

    Crevice corrosion occurs when two pieces of metal touch each other, leaving a small gap or __________ between the metals.

    <p>crevice</p> Signup and view all the answers

    Match the types of corrosion with their descriptions:

    <p>Uniform corrosion = Occurs evenly over a large portion of the surface Galvanic corrosion = Occurs when two different metals contact each other Crevice corrosion = Occurs in small gaps between metals Pitting corrosion = Localized corrosion creating small holes</p> Signup and view all the answers

    Match each component of a galvanic cell with its correct description:

    <p>Anode = Electrode where oxidation occurs Cathode = Electrode where reduction occurs Salt bridge = Allows ions to flow between half-cells Cell notation = Shorthand notation for electrochemical processes</p> Signup and view all the answers

    Which ions flow into the Ag+ beaker from the salt bridge composed of NH4Cl?

    <p>NH4+</p> Signup and view all the answers

    What is the primary product of corrosion when iron reacts with oxygen?

    <p>Iron(III) oxide</p> Signup and view all the answers

    Oxidation-reduction reactions involve the transfer of electrons between reactants.

    <p>True</p> Signup and view all the answers

    Electrochemical cells operate at standard state conditions with electrolyte concentrations of 1 M.

    <p>True</p> Signup and view all the answers

    What type of electrolyte is needed in a salt bridge?

    <p>strong electrolyte</p> Signup and view all the answers

    Name one common technique for preventing corrosion.

    <p>Galvanization or coating with paint or plastic</p> Signup and view all the answers

    What occurs at the cathode in a galvanic cell?

    <p>Reduction of cations</p> Signup and view all the answers

    The cell potential, or electromotive force (EMF), is unrelated to the maximum work obtainable from an electrochemical cell.

    <p>False</p> Signup and view all the answers

    What is the maximum work obtainable from an electrochemical cell expressed as an equation?

    <p>w = qE</p> Signup and view all the answers

    Without a ______, local charges can build up around electrodes, preventing significant electrode reactions.

    <p>salt bridge</p> Signup and view all the answers

    Match the type of corrosion with its characteristic:

    <p>Galvanic corrosion = Occurs between two metals in contact Uniform corrosion = Involves a nonmetal in the corrosion process</p> Signup and view all the answers

    Which statement is true regarding galvanic corrosion?

    <p>Galvanic corrosion occurs when two metals are in contact with moisture.</p> Signup and view all the answers

    The presence of ionic salts can slow down the corrosion of metals.

    <p>False</p> Signup and view all the answers

    What substance is required for ion mobility during the corrosion of iron?

    <p>Water</p> Signup and view all the answers

    What major goal was achieved by using lithium-ion batteries in the Boeing Dreamliner?

    <p>Increased fuel efficiency</p> Signup and view all the answers

    Lithium-ion batteries incorporate lithium in both the anode and cathode.

    <p>True</p> Signup and view all the answers

    Name one reason why lithium-ion batteries have a high energy density.

    <p>Li+/Li has one of the largest standard reduction potentials.</p> Signup and view all the answers

    The anode of a lithium-ion battery is primarily made of ______.

    <p>graphite</p> Signup and view all the answers

    Match the part of the battery with its material:

    <p>Anode = Graphite Cathode = Cobalt oxide Electrolyte = Lithium salt solution Separator = Porous membrane</p> Signup and view all the answers

    What is the role of the anode in electrolysis?

    <p>It becomes the positive electrode</p> Signup and view all the answers

    The Hall-Heroult process is used to separate aluminum from its oxide through spontaneous reactions.

    <p>False</p> Signup and view all the answers

    What is the purpose of electroplating?

    <p>To deposit a thin coat of metal on another metal.</p> Signup and view all the answers

    In electroplating, the object being coated is referred to as the ______.

    <p>cathode</p> Signup and view all the answers

    Which substance is commonly plated onto electrical devices for its conductive properties?

    <p>Silver</p> Signup and view all the answers

    The flow of ions through the solution in electrolysis helps to complete the electrical circuit.

    <p>True</p> Signup and view all the answers

    Electrolysis enables the separation of aluminum from its oxide, which is represented by the formula ______.

    <p>Al2O3</p> Signup and view all the answers

    What is the potential measured for a copper/silver cell?

    <p>0.462 V</p> Signup and view all the answers

    Reversing the poles of a battery affects the electrochemical reaction in the battery.

    <p>False</p> Signup and view all the answers

    What is assigned a potential of exactly zero volts?

    <p>Standard Hydrogen Electrode (SHE)</p> Signup and view all the answers

    The SHE is immersed in a 1 M __________ solution.

    <p>HCl</p> Signup and view all the answers

    Which component acts as the reference point for the scale of standard reduction potentials?

    <p>Standard Hydrogen Electrode</p> Signup and view all the answers

    The SHE can act as both an anode and a cathode depending on the galvanic cell arrangement.

    <p>True</p> Signup and view all the answers

    What is the half-cell notation for the Standard Hydrogen Electrode?

    <p>Pt(s) | H2(g, 1 atm) | H+(1 M)</p> Signup and view all the answers

    Which of the following statements about zinc-air batteries is true?

    <p>They have a high energy density due to the use of oxygen from the air.</p> Signup and view all the answers

    The nickel-metal-hydride battery is an example of a primary battery.

    <p>False</p> Signup and view all the answers

    What substance is used as the electrolyte in a lead-acid battery?

    <p>sulfuric acid</p> Signup and view all the answers

    In a fuel cell, hydrogen is oxidized at the ______.

    <p>anode</p> Signup and view all the answers

    Match the battery types with their characteristics:

    <p>Zinc-air battery = Uses oxygen from air Nickel-metal-hydride battery = Rechargeable cell Lead-acid battery = Used in cars Fuel cell = Produces water from hydrogen and oxygen</p> Signup and view all the answers

    What is a major limitation of batteries?

    <p>Corrosion affecting performance</p> Signup and view all the answers

    In electrolysis, the cathode is always negatively charged.

    <p>True</p> Signup and view all the answers

    What type of electrodes are used in passive electrolysis?

    <p>chemically inert materials</p> Signup and view all the answers

    What is the primary component of an alkaline battery that undergoes oxidation?

    <p>Zinc</p> Signup and view all the answers

    Lithium batteries can be recharged multiple times.

    <p>False</p> Signup and view all the answers

    What is the main purpose of a battery?

    <p>To generate electrical current from chemical reactions.</p> Signup and view all the answers

    In a zinc-air battery, zinc acts as the ______.

    <p>anode</p> Signup and view all the answers

    Match each type of primary cell with its description:

    <p>Alkaline battery = Single-use battery with zinc electrode Lithium battery = Long-lasting battery used in medical devices Zinc-air battery = Uses oxygen as a reactant at the cathode Carbon-zinc battery = Commonly used for low-drain devices</p> Signup and view all the answers

    Which statement is true regarding the relationship between cell potential and equilibrium constant?

    <p>As the cell potential increases, the equilibrium constant also increases.</p> Signup and view all the answers

    An alkaline battery contains a liquid electrolyte.

    <p>False</p> Signup and view all the answers

    What is the net reaction in an alkaline dry cell battery?

    <p>Zinc oxidizes, and manganese(IV) oxide reduces.</p> Signup and view all the answers

    What is the main purpose of the Hall-Heroult refining process?

    <p>To separate aluminum from its oxide</p> Signup and view all the answers

    The anode in electrolysis is the positive electrode.

    <p>True</p> Signup and view all the answers

    What ions are involved in the electroplating of silver?

    <p>Ag+</p> Signup and view all the answers

    In electroplating, the object being coated is known as the ______.

    <p>cathode</p> Signup and view all the answers

    Match the following processes with their descriptions:

    <p>Hall-Heroult Process = Refining aluminum from its oxide Electroplating = Depositing a metal coating onto another metal Barrel Plating = Coating small parts Passive Electrolysis = Inert site for electrolysis</p> Signup and view all the answers

    Which of the following is a common outcome of electrolysis in aluminum refining?

    <p>Separation of aluminum metal</p> Signup and view all the answers

    Electroplating can only be performed with silver.

    <p>False</p> Signup and view all the answers

    What drives the nonspontaneous reaction in electrolysis?

    <p>External current</p> Signup and view all the answers

    What is a primary advantage of using lithium-ion batteries in the Boeing Dreamliner?

    <p>High energy capacity</p> Signup and view all the answers

    High temperatures do not affect the degradation of lithium-ion batteries.

    <p>False</p> Signup and view all the answers

    What role do lithium ions play in the anode of a lithium-ion battery?

    <p>Lithium ions are intercalated into the graphite structure of the anode.</p> Signup and view all the answers

    The cathode in a lithium-ion battery primarily consists of __________ oxide.

    <p>cobalt</p> Signup and view all the answers

    Match the following components of lithium-ion batteries with their descriptions:

    <p>Anode = Graphite containing intercalated lithium Cathode = Cobalt oxide with lithium Li+/Li = High standard reduction potential Energy density = Lightweight materials increase efficiency</p> Signup and view all the answers

    What is the unit of current in an electric circuit?

    <p>Ampere</p> Signup and view all the answers

    Using Faraday's constant, the number of moles of electrons that pass through a circuit can be calculated.

    <p>True</p> Signup and view all the answers

    What is the energy cost in kilowatt-hours for a process running at 15.0 A for 2 hours if the utility charges $0.0500 per kWh?

    <p>Calculate using the formula: Energy cost = Power (kW) x Time (h) x Rate ($/kWh)</p> Signup and view all the answers

    Electricity consumption is typically measured in kilowatt-________.

    <p>hours</p> Signup and view all the answers

    How long does an electrolysis cell operating at 2.30 A need to run to deposit a specific mass of gold?

    <p>Is determined by the charge passing through</p> Signup and view all the answers

    What is the formula to find the charge in electrolysis with known current and time?

    <p>Charge (Q) = Current (I) x Time (t)</p> Signup and view all the answers

    Flash electroplating involves low current and long time.

    <p>False</p> Signup and view all the answers

    Which type of corrosion occurs evenly over a large surface area of a metal?

    <p>Uniform corrosion</p> Signup and view all the answers

    Iron oxide corrosion product flakes off from the surface of iron.

    <p>True</p> Signup and view all the answers

    What is the main component of aluminum oxide that protects aluminum from further corrosion?

    <p>Aluminum oxide</p> Signup and view all the answers

    The degradation of metals by chemical reactions with the environment is known as ______.

    <p>corrosion</p> Signup and view all the answers

    Match the types of batteries with their characteristics:

    <p>Primary batteries = Non-rechargeable batteries Secondary batteries = Rechargeable batteries Lead-acid batteries = Commonly used in vehicles Lithium-ion batteries = High energy density applications</p> Signup and view all the answers

    What is one technique for preventing corrosion?

    <p>Applying paint or coatings</p> Signup and view all the answers

    In a galvanic cell, what occurs at the anode?

    <p>Oxidation</p> Signup and view all the answers

    Crevice corrosion occurs when two metals are in direct contact without any gap.

    <p>False</p> Signup and view all the answers

    What happens to copper metal when it interacts with silver cation in silver nitrate solution?

    <p>Copper is oxidized, and silver is reduced.</p> Signup and view all the answers

    The reducing agent in the redox reaction between copper and silver nitrate is the silver cation.

    <p>False</p> Signup and view all the answers

    What ion is responsible for the blue color observed in the silver nitrate solution after the reaction with copper occurs?

    <p>Cu2+</p> Signup and view all the answers

    In a galvanic cell, the process of converting __________ energy into electrical energy occurs through spontaneous reactions.

    <p>chemical</p> Signup and view all the answers

    Match the following terms with their corresponding definitions:

    <p>Reducing agent = Species that loses electrons Oxidizing agent = Species that gains electrons Oxidation = Loss of electrons Reduction = Gain of electrons</p> Signup and view all the answers

    What must occur concurrently in an oxidation-reduction reaction?

    <p>Oxidation and reduction must occur together.</p> Signup and view all the answers

    In the formation of silver metal from silver cation, the reaction shows silver accepting two electrons.

    <p>False</p> Signup and view all the answers

    What is formed on the surface of the copper wire when it is placed in silver nitrate solution?

    <p>Silver metal</p> Signup and view all the answers

    What happens to the measured potential when the cathode is connected to the positive terminal of the voltmeter?

    <p>The potential is positive.</p> Signup and view all the answers

    The SHE is always considered the anode when the measured potential is negative.

    <p>True</p> Signup and view all the answers

    What reaction occurs at the cathode in a galvanic cell?

    <p>Reduction of H+(aq) to H2</p> Signup and view all the answers

    A positive standard reduction potential indicates that the half-reaction proceeds as __________.

    <p>reduction</p> Signup and view all the answers

    Match the half-reaction sign with its corresponding description:

    <p>Positive Sign = Indicates reduction Negative Sign = Indicates oxidation Zero Sign = Indicates no net reaction Reversed Sign = The half-reaction is reversed</p> Signup and view all the answers

    What occurs if the leads of the voltmeter are reversed?

    <p>The sign of the reading changes.</p> Signup and view all the answers

    What must be true about one of the half-reactions in an electrochemical cell?

    <p>It must be an oxidation.</p> Signup and view all the answers

    Standard reduction potentials are listed as oxidations in tables.

    <p>False</p> Signup and view all the answers

    What is a primary cell?

    <p>A single-use battery</p> Signup and view all the answers

    Lithium batteries are often used in medical devices like pacemakers.

    <p>True</p> Signup and view all the answers

    What is the function of the anode in an alkaline battery?

    <p>It acts as the site of oxidation.</p> Signup and view all the answers

    In zinc-air batteries, zinc is the ______.

    <p>anode</p> Signup and view all the answers

    Match the following types of batteries with their characteristics:

    <p>Alkaline Battery = Single-use, uses zinc as anode Lithium Battery = Long-lasting, used in medical devices Zinc-air Battery = Uses oxygen at the cathode Rechargeable Battery = Can be used multiple times</p> Signup and view all the answers

    What happens to the equilibrium constant as the cell potential increases?

    <p>It increases</p> Signup and view all the answers

    An alkaline battery is called a dry cell because its electrolyte is in liquid form.

    <p>False</p> Signup and view all the answers

    What is the primary composition of an alkaline battery's cathode?

    <p>Manganese(IV) oxide</p> Signup and view all the answers

    What is the main reactant for zinc-air batteries?

    <p>Oxygen from the air</p> Signup and view all the answers

    The lead-acid storage battery contains an anode made of lead oxide.

    <p>False</p> Signup and view all the answers

    Name one advantage of nickel-metal-hydride batteries as rechargeable cells.

    <p>High energy density</p> Signup and view all the answers

    In a fuel cell, the products of the cell reaction are continuously _______.

    <p>removed</p> Signup and view all the answers

    Which of the following best describes a fuel cell?

    <p>A voltaic cell where reactants are continuously supplied</p> Signup and view all the answers

    Match the type of electrolysis with its description:

    <p>Passive electrolysis = Electrodes are inert materials Active electrolysis = Electrodes participate in the reaction</p> Signup and view all the answers

    Corrosion has no significant effect on the performance of batteries.

    <p>False</p> Signup and view all the answers

    What happens to the electrodes during electrolysis?

    <p>The polarity of the electrodes changes.</p> Signup and view all the answers

    What are the primary materials used in the electrodes of lithium-ion batteries?

    <p>Graphite and cobalt oxide</p> Signup and view all the answers

    A major advantage of lithium-ion batteries is that they perform well at high temperatures.

    <p>False</p> Signup and view all the answers

    What was a key goal in the design of the Boeing Dreamliner regarding its energy source?

    <p>Minimize weight for increased fuel efficiency</p> Signup and view all the answers

    Li+/Li has one of the largest standard reduction potentials due to the __________ of lithium.

    <p>lightness</p> Signup and view all the answers

    Match the components of a lithium-ion battery with their respective functions:

    <p>Anode = Stores lithium ions Cathode = Releases lithium ions Electrolyte = Conducts ions between electrodes Separator = Prevents short circuits</p> Signup and view all the answers

    What is the function of the salt bridge in a galvanic cell?

    <p>To allow ions to flow between half-cells</p> Signup and view all the answers

    The electrode where reduction occurs is called the anode.

    <p>False</p> Signup and view all the answers

    The flow of NH4+ into the Ag+ beaker from a salt bridge is meant to offset the removal of __________ from the solution.

    <p>Ag+</p> Signup and view all the answers

    Match the following components of a galvanic cell with their roles:

    <p>Anode = Where oxidation occurs Cathode = Where reduction occurs Salt bridge = Allows ion migration Metal wire = Conducts electrons</p> Signup and view all the answers

    Which ions flow into the Cu2+ beaker from a salt bridge composed of NH4Cl?

    <p>Cl-</p> Signup and view all the answers

    Before the half-cells are connected, charge build up occurs at the interface between the electrode and the electrolyte.

    <p>True</p> Signup and view all the answers

    In the context of galvanic cells, what does the double vertical line '||' denote in cell notation?

    <p>The salt bridge</p> Signup and view all the answers

    What happens to copper when it is placed in a silver nitrate solution?

    <p>Copper loses electrons.</p> Signup and view all the answers

    In a redox reaction, oxidation can occur without reduction.

    <p>False</p> Signup and view all the answers

    What is the resulting color of the silver nitrate solution once copper is added?

    <p>blue</p> Signup and view all the answers

    The process of ______ is when a chemical species gains electrons.

    <p>reduction</p> Signup and view all the answers

    What is the role of the copper wire in the redox reaction with silver nitrate?

    <p>Reducing agent</p> Signup and view all the answers

    Match each term with its corresponding definition:

    <p>Oxidation = Loss of electrons Reduction = Gain of electrons Reducing agent = Species that donates electrons Oxidizing agent = Species that accepts electrons</p> Signup and view all the answers

    Which statement is true regarding the half-reactions in the copper-silver redox reaction?

    <p>The silver cation accepts only one electron.</p> Signup and view all the answers

    What does a galvanic cell convert into electric current?

    <p>spontaneous chemical reaction</p> Signup and view all the answers

    What does a large positive value for the standard reduction potential imply?

    <p>The substance is a good oxidizing agent.</p> Signup and view all the answers

    The half-reaction with the less positive reduction potential is the anode in a galvanic cell.

    <p>True</p> Signup and view all the answers

    What is the standard reduction potential for the cathode represented as?

    <p>E°</p> Signup and view all the answers

    A galvanic cell with a negative Gibbs free energy change indicates a __________ process.

    <p>spontaneous</p> Signup and view all the answers

    In the Nernst equation, what does 'Q' represent?

    <p>Reaction quotient</p> Signup and view all the answers

    Match each term with its correct definition:

    <p>Cathode = Electrode where reduction occurs Anode = Electrode where oxidation occurs E°cell = Standard reduction potential for the cell F = Faraday constant</p> Signup and view all the answers

    A large negative standard reduction potential indicates that a substance is a good oxidizing agent.

    <p>False</p> Signup and view all the answers

    What is the value of the Faraday constant?

    <p>96,485 C mol-1</p> Signup and view all the answers

    What is one of the reactants used in a zinc-air battery?

    <p>Oxygen</p> Signup and view all the answers

    Lead-acid batteries utilize lead metal as both the anode and cathode.

    <p>False</p> Signup and view all the answers

    What is the primary product of the reaction between hydrogen and oxygen in a fuel cell?

    <p>water</p> Signup and view all the answers

    The process of passing an electric current through an ionic solution is known as __________.

    <p>electrolysis</p> Signup and view all the answers

    Match the following types of batteries with their common uses:

    <p>Nickel-metal-hydride = Rechargeable batteries in household items Lead-acid = Car batteries Zinc-air = Hearing aids Lithium-ion = Portable electronics</p> Signup and view all the answers

    In a nickel-metal-hydride battery, what reaction occurs at the anode?

    <p>Oxidation of nickel</p> Signup and view all the answers

    Corrosion only affects the performance of batteries but not their lifespan.

    <p>False</p> Signup and view all the answers

    Name one of the limitations of batteries discussed in the content.

    <p>corrosion</p> Signup and view all the answers

    What happens when the standard hydrogen electrode (SHE) is connected to the positive terminal of a voltmeter?

    <p>It indicates the SHE is the cathode.</p> Signup and view all the answers

    In a galvanic cell, electrons flow from the cathode to the anode.

    <p>False</p> Signup and view all the answers

    What occurs at the cathode during a redox reaction?

    <p>Reduction</p> Signup and view all the answers

    What does a positive standard reduction potential indicate in an electrochemical cell?

    <p>The SHE is the cathode.</p> Signup and view all the answers

    Reversing the leads of the voltmeter changes the flow of current in the circuit.

    <p>False</p> Signup and view all the answers

    In measuring cell potential, the SHE is connected to the __________ terminal of the voltmeter.

    <p>positive</p> Signup and view all the answers

    What is the primary component used in an alkaline battery for oxidation?

    <p>Zinc</p> Signup and view all the answers

    What chemical reaction is involved in the functioning of a zinc-air battery?

    <p>Zinc acts as the anode while oxygen reacts at the cathode.</p> Signup and view all the answers

    The thermodynamic relationship between cell potential and the equilibrium constant can be expressed using the equation: E = ______.

    <p>RT/nF ln(K)</p> Signup and view all the answers

    Match the following battery types with their characteristics:

    <p>Alkaline Battery = Single-use with zinc at the anode Lithium Battery = Long-lasting for medical devices Zinc-Air Battery = Uses zinc as the anode and oxygen as the cathode Primary Cell = Cannot be recharged once depleted</p> Signup and view all the answers

    Which statement about batteries is true?

    <p>Batteries harness the electrical work of a galvanic cell.</p> Signup and view all the answers

    The equilibrium constant decreases as the cell potential increases.

    <p>False</p> Signup and view all the answers

    What is the purpose of a galvanic cell?

    <p>To convert chemical energy into electrical energy.</p> Signup and view all the answers

    What is the primary role of the copper metal in the reaction with silver nitrate?

    <p>It is oxidized and acts as the reducing agent.</p> Signup and view all the answers

    In a galvanic cell, oxidation and reduction reactions occur simultaneously.

    <p>True</p> Signup and view all the answers

    What color change is observed in the silver nitrate solution when copper wire is placed in it?

    <p>The solution turns blue.</p> Signup and view all the answers

    The species that is reduced in a redox reaction is known as the __________ agent.

    <p>oxidizing</p> Signup and view all the answers

    How many electrons does Ag+ gain to become silver metal?

    <p>One electron</p> Signup and view all the answers

    Copper loses two electrons to form Cu2+ ions in the solution.

    <p>True</p> Signup and view all the answers

    What byproduct forms on the surface of the copper wire during the reaction with silver nitrate?

    <p>Silver metal</p> Signup and view all the answers

    What is the main purpose of a salt bridge in a galvanic cell?

    <p>To allow ions to flow between half-cells</p> Signup and view all the answers

    The anode of a galvanic cell is where reduction occurs.

    <p>False</p> Signup and view all the answers

    What is measured as the voltage potential for a copper/silver galvanic cell?

    <p>0.46 V</p> Signup and view all the answers

    The electrode where __________ occurs is known as the cathode.

    <p>reduction</p> Signup and view all the answers

    Match the following components of a galvanic cell with their respective roles:

    <p>Anode = Site of oxidation Cathode = Site of reduction Salt Bridge = Completes electrical circuit Metal Wire = Transfers electrons between electrodes</p> Signup and view all the answers

    What will flow into the Ag+ beaker from a salt bridge composed of NH4Cl during operation?

    <p>NH4+ ions</p> Signup and view all the answers

    The half-reaction involving Cu metal occurs in a separate half-cell from the reaction involving Ag metal.

    <p>True</p> Signup and view all the answers

    What is required for an electrochemical cell to be in standard state conditions?

    <p>1 M electrolyte concentration and 1 atm partial pressure for gases</p> Signup and view all the answers

    What is the relationship between EMF and the maximum work obtainable from an electrochemical cell?

    <p>EMF is related to the maximum work obtainable.</p> Signup and view all the answers

    The presence of a salt bridge can prevent the buildup of local charges around electrodes.

    <p>True</p> Signup and view all the answers

    What occurs to the charge of the cathode during reduction?

    <p>It becomes positively charged.</p> Signup and view all the answers

    For the corrosion of iron, water is needed for ______ mobility between the anodic and cathodic regions.

    <p>ion</p> Signup and view all the answers

    Match the type of corrosion with its description:

    <p>Galvanic corrosion = Occurs when two different metals are in contact in the presence of an electrolyte Uniform corrosion = Occurs in the absence of contact between different metals Pitting corrosion = Localized corrosion that can occur on the surface of metals Crevice corrosion = Occurs in small gaps between metal surfaces</p> Signup and view all the answers

    What is a major factor that speeds up the corrosion reaction?

    <p>Presence of ionic salts</p> Signup and view all the answers

    In a galvanic cell, what is the role of the anode?

    <p>It is where oxidation occurs.</p> Signup and view all the answers

    Oxidation occurs at the cathode in an electrochemical cell.

    <p>False</p> Signup and view all the answers

    What role does the cathode play in a galvanic cell?

    <p>Site of reduction</p> Signup and view all the answers

    A negative cell potential indicates that the SHE is functioning as the cathode.

    <p>False</p> Signup and view all the answers

    What is the effect of reversing the leads of a voltmeter on the reading?

    <p>It changes the sign of the reading but does not influence the flow of current.</p> Signup and view all the answers

    When the half-reaction is written as oxidation, the sign of the cell potential must be __________.

    <p>changed</p> Signup and view all the answers

    Match the following terms with their meanings:

    <p>Anode = Site of oxidation Cathode = Site of reduction Standard Reduction Potential = Tendency of a half-reaction to gain electrons Galvanic Cell = Device that converts chemical energy to electrical energy</p> Signup and view all the answers

    Which of the following statements is true regarding half-reactions in electrochemistry?

    <p>At least one half-reaction must be an oxidation.</p> Signup and view all the answers

    Standard reduction potentials are always measured with the SHE at the negative terminal.

    <p>False</p> Signup and view all the answers

    Define the term 'Standard Hydrogen Electrode' (SHE).

    <p>A reference electrode with a potential of 0 volts.</p> Signup and view all the answers

    What does a large, positive value for the standard reduction potential indicate about a substance?

    <p>It is readily reduced and acts as a good oxidizing agent.</p> Signup and view all the answers

    The cathode in a galvanic cell corresponds to the half-reaction with the less positive reduction potential.

    <p>False</p> Signup and view all the answers

    In nonstandard conditions, the cell potential can be calculated using the __________ equation.

    <p>Nernst</p> Signup and view all the answers

    At what concentration of H+ does the cell potential need to be calculated as per the example provided?

    <p>1.0 × 10-3 M</p> Signup and view all the answers

    Match the following terms with their associated values:

    <p>Faraday's constant = 96,485 J V-1 mol-1 Reduction potential = Cathode Oxidation potential = Anode Gibbs free energy change = Negative for spontaneous reactions</p> Signup and view all the answers

    Corrosion has a positive Gibbs free energy change.

    <p>False</p> Signup and view all the answers

    What happens to the value of Gibbs free energy when the cell potential is positive?

    <p>It is negative.</p> Signup and view all the answers

    What is the primary purpose of the Hall-Heroult process?

    <p>To separate aluminum from its oxide</p> Signup and view all the answers

    During electrolysis, the anode is the negative electrode.

    <p>False</p> Signup and view all the answers

    What ions are present in the solution used for electroplating silver?

    <p>Ag+ and CN–</p> Signup and view all the answers

    What role does carbon play in the Hall-Heroult process?

    <p>It is an inert site for passive electrolysis</p> Signup and view all the answers

    Electrolysis is a spontaneous process.

    <p>False</p> Signup and view all the answers

    What is one benefit of silver electroplating on electrical devices?

    <p>Corrosion resistance or better conductivity</p> Signup and view all the answers

    Study Notes

    Chapter 13: Electrochemistry

    • Corrosion is the degradation of metals by chemical reactions with the environment
    • Uniform corrosion occurs evenly across a large portion of a metal's surface
    • Galvanic corrosion occurs when two different metals contact each other in the presence of an electrolyte
    • Crevice corrosion occurs when two pieces of metal touch each other, creating a small gap or crevice between them
    • Different metals corrode differently
    • Aluminum has a higher tendency to corrode than iron, but aluminum oxide forms a protective layer
    • Iron oxide corrosion product flakes off, exposing fresh iron to corrosion
    • Corrosion occurs in various forms, including uniform and crevice corrosion

    Oxidation-Reduction Reactions and Galvanic Cells

    • Special conditions are needed for iron to react with oxygen to form iron(III) oxide
    • Rust formation is a slow process
    • Reactions transferring electrons between reactants are redox reactions
    • Oxidation is the loss of electrons
    • Reduction is the gain of electrons
    • For a redox reaction, one reactant must be oxidized and one must be reduced
    • Oxidation cannot occur without reduction
    • When copper wire is placed in a silver nitrate solution, a redox reaction occurs

    Oxidation-Reduction and Half-Reactions

    • The solution's blue color indicates copper(II) ions in solution
    • Copper(II) forms when a copper atom loses two electrons
    • The copper metal is oxidized
    • Silver forms on the surface of the copper wire when a silver cation gains an electron
    • The silver cation is reduced
    • For the reaction between silver cation and copper metal, two half-reactions are written: one for copper's oxidation and one for silver's reduction
    • Neither half-reaction can occur without the other
    • The half-reactions need to balance the electrons transferred
    • Adding the half-reactions together, cancel out the electrons to get the net reaction
    • The species undergoing oxidation is a reducing agent
    • The species undergoing reduction is an oxidizing agent

    Building a Galvanic Cell

    • A galvanic cell is any electrochemical cell where a spontaneous reaction produces an electric current
    • To harness electricity from a galvanic cell, each half-reaction is prepared in separate half-cells in a galvanic cell
    • Cu metal immersed in Cu2+ solution is one half-cell
    • Ag metal immersed in Ag+ solution is the other half-cell
    • A salt bridge allows ions to flow between each half-cell, completing the circuit
    • Current flows through the migration of ions in solution
    • The salt bridge contains a strong electrolyte that allows either cations or anions to migrate to maintain charge neutrality
    • A metal wire cannot transport ions

    Terminology for Galvanic Cells

    • Electrodes are the electrically-conducting sites where oxidation or reduction occurs
    • The electrode where oxidation occurs is the anode
    • The electrode where reduction occurs is the cathode
    • Cell notation lists the metals and ions involved in the reaction
    • A vertical line (|) denotes a phase boundary
    • A double vertical line (||) denotes a salt bridge
    • The anode is written on the left, the cathode on the right

    Standard Reduction Potentials

    • To compare oxidation-reduction trends of species in electrochemistry, half-cell potentials are written as reductions
    • A table of standard reduction potentials lists the potential of any half-reaction when connected to a standard hydrogen electrode (SHE)
    • All materials are 1 M for aq species and 1 atm for gases
    • Although half-reactions are listed as reductions, one half reaction in any electrochemical cell must be an oxidation
    • The cell potential sign must change when writing the half-reaction as an oxidation
    • All potentials are measured with a SHE connected to the positive terminal
    • A positive voltage means the SHE is the anode, the oxidation site
    • A negative voltage means the SHE is the cathode, the reduction site
    • The tendency for a reaction to be oxidation or reduction depends on the reduction potential
    • A large, positive value implies a substance is reduced readily and a good oxidizing agent
    • A large, negative value implies a substance is oxidized readily and a good reducing agent
    • For a galvanic cell, the half-reaction with the more positive reduction potential is the cathode, the one with the more negative reduction potential is the anode
    • The standard reduction potential is calculated from the reduction potentials of the cathode and anode

    Nonstandard Conditions

    • The cell potential at nonstandard conditions is calculated by the Nernst equation
    • The reaction quotient is Q, Faraday's constant is F, and the number of electrons transferred is n

    Example Problems

    • Multiple example problems are provided involving calculations involving electrochemistry

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    Chapter 13 Electrochemistry PDF

    Description

    Explore the critical concepts of electrochemistry in this quiz covering corrosion types, redox reactions, and galvanic cells. Understand how metals interact with their environments, including uniform and crevice corrosion, as well as the formation of rust. Test your knowledge on these fundamental reactions and their implications in chemical processes.

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