Wenner Practice NACE CP2 - EXAM (2) Latest Updated Graded A+

NACE 2008 Student Manual! START OF CHAPTER 1 Corrosion is an electrochemical process involving A) flow of protons and electrons B) flow of neutrons and ions C) flow of protons and ions D) flow of electrons and ions E) flow of resistance and resistivity - ANSWER-d Metal loss or corrosion occurs at the A) cathode B) anode C) electronic path D) metallic path - ANSWER-b What are the four parts of the corrosion cell A) anode, resistor, electrolyte, metallic path B) anode, cathode, electron, electronic path C) anode, cathode, electrolyte, metallic path - ANSWER-c True or False (t or f): Ions exist only in the electrolyte? - ANSWER-t Electrons flow in a corrosion cell by which of the following paths? A) anode to cathode via electrolyte B) cathode to anode via electronic path C) anode to cathode via electronic path - ANSWER-c At the cathodic surface in a corrosion cell, the electrons from the ____ meet ____ ions from the solution. A) cathode, hydrogen B) cathode, OH- C) anode, hydrogen D) anode, OH- - ANSWER-c Oxidation of the metal occurs at the ____ surfaces and reduction of ____ ions occurs at the ____. A) anodic, hydrogen, cathodes B) cathode, OH-, anodic C) anodic, OH-, cathodes D) cathode, anodic, electrolyte E) cathode, hydrogen, electrolyte - ANSWER-a True or false Is oxidation necessarily associated with oxygen? - ANSWER-f _____ is the measure of the electrochemical difference between two electrodes in an electrolyte A) current B) resistance C) error D) ohms E) ohms-cm F) voltage - ANSWER-f The ________ represents the reversible work to move a unit charge from the electrode surface through the solution to the reference electrode A) current potential B) electrode potential C) resistance potential D) ohms potential E) Faraday potential - ANSWER-b Metals occur in nature in the form of various chemical compounds referred to as ___ A) ores B) anodic metals C) cathodic metals D) carbohydrates - ANSWER-a The amount of energy required by a metal during the refining process determines the ___ or _______ of the metal. A) current, active state B) voltage, active state C) active resistance, voltage D) resistance, active state E) current, active resistance - ANSWER-b During the refining stage of metal the ____ the energy, the more ____ the metal and the more tendency it has to corrode. A) higher, inactive B) lower, active C) higher, active D) lower, inactive - ANSWER-c What is the most common iron ore? A) hemophite B) hematite C) magnesium D) calcium E) aluminum - ANSWER-b True or false Iron is considered thermodynamically unstable? - ANSWER-t True or false Gold is more noble than zinc? - ANSWER-t Which of the following metals is most active? A) magnesium B) copper C) iron D) nickel E) platinum - ANSWER-a Electromotive force (emf), is ____ in sign and magnitude to the electrode potential of the ___ less the electrode potential of the ____. A) unequal, cathode, anode B) unequal, anode, cathode C) equal, cathode, anode D) equal, anode, cathode - ANSWER-d The driving force for electrochemical corrosion is ____ A) current B) voltage C) resistance D) ohms E) siemens-cm - ANSWER-b In relation to a corrosion cell, ____ is the net transfer of electric charge per unit time A) current B) voltage C) resistance D) ohms E) siemens-cm - ANSWER-a If a metallic path connects two electrodes inside an electrolyte, the ____ difference will cause a ____ to flow between them A) current, voltage B) resistance, current C) resistance, voltage D) voltage, current E) current, resistance - ANSWER-d The more useful method of organizing metals in order of their tendency to corrode is _____ A) emf series B) pgp series C) nuclear series D) electron series E) galvanic series - ANSWER-e The ____ expresses the exact electromotive force of a cell in terms of the activities of products and reactants of the cell A) Ernest Equation B) Faraday Equation C) Ohm's Law Equation D) Nernst Equation E) Uniform Equation - ANSWER-d Given the Nernst Equation, using the Valence of Common Metals Table, and using the partial Standard emf Series of Metals solve: What is the potential of zinc in a 0.01 molar zinc chloride solution at 25C? A) -0.892V B) -0.287V C) -0.827V D) -0.297V E) -0.889V - ANSWER-c E= -0.763 + (0.059/2) * log (0.71 *0.01/1) = -0.827V Standard conditions for pure metals in the emf series are based on one unit activity of metal ions in the electrolyte at ___ C with no impurities in the metal or electrolyte and with reference to a standard ____ electrode. A) 25, hydrogen B) 35, hydrogen C) 25, CSE D) 35, CSE E) 25, SSC F) 35, SSC - ANSWER-a The ____ the concentration of metal ions in the electrolyte, the ____ the metal. A) lower, less active B) higher, less active C) lower, more active D) higher, less active - ANSWER-b In reference to the temperature in a corrosion cell, in most cases, electrode at the _____ temperature becomes the ____ A) lower, anode B) higher, cathode C) lower, cathode D) higher, anode - ANSWER-d During metal fabrication of structures, highly stressed areas of a metal will tend to be at ____ energy levels, thus more ____ than less stressed areas A) higher, active B) lower, active C) higher, inactive D) lower, inactive - ANSWER-a True or False (t or f): Corrosion cells may form because of differences in the electrolyte - ANSWER-t ____ cells are responsible for much of the corrosion that take place in soils, particularly in bare or poorly coated pipe A) concentration B) steady state C) carbon D) dynamic E) telluric - ANSWER-a In many cases in naturally occurring soils, a portion of pipe lying in the more _____ soil is the ____ and in the less ____soil is the ___. A) inductive, anode / inductive, cathode B) inductive, cathode / inductive, anode C) conductive, anode / conductive, cathode D) conductive, cathode /conductive, anode - ANSWER-c The two most common types of concentration cells involved in promoting corrosion are ____ and ____. A) oxygen, nonmettalic ion B) oxygen, calcium C) lack of oxygen, metal ion D) oxygen, metal ion - ANSWER-d What is the most common of the cathodic depolarizers, that can maintain and promote a cathodic reaction?