BASIC CHEMISTRY AND BASIC CORROSION THEORY Flashcards
negatively charged ion electrons greater than protons
anion anode
positively charge ion protons greater than electrons
cation cathode
how acid the solution is
excess of hydrogen (H+) ions
how alkaline the solution is
excess of hydroxyl (OH-) ions
pH neutral
7
acid pH
less than 7
alkaline pH
greater than 7
between 4 and 8 corrosion is fairly _____ of pH
independent
the pH of the environment around the cathode (the protected structure) becomes more _____ due to the production of hydroxyl ions or removal of hydrogen ions.
alkaline
term applied to the loss of one or more electrons from an atom or molecule, which then forms a positively charge ion
oxidation
the electrode or metallic site where oxidation occurs is called an
anode
the term applied to the gain of one or more electrons to an atom or molecule
reduction
the electrode or metallic site where reduction occurs is called a
cathode
4 parts of ______ ____ are anode, cathode, electrolyte,metallic path
corrosion cell
metal loss occurs at the
anode
the anode and the cathode can be on different metals or on the ______ metal
same
positively charged ions move away from the ______ and toward the _________
anode cathode
when measuring voltage across an element of a circuit, the voltmeter is connected in _____ across the element.
parallel
when a voltmeter is connected across a metallic element, such as a wire or pipeline with external current flow, the voltage display is positive when the ______ ______ of the voltmeter is upstream of the current flow.
positive terminal
when measuring the voltage difference of dissimilar metals, the sign is positive when the positive terminal of the voltmeter is connected to the more ______ _____
noble metal
structure-to-soil potentials are measured in reference to an __________
electrode (copper copper sulfate)
there must be a voltage difference between the anode and cathode of a corrosion cell for ________ to flow
current
the deviation from the open circuit potential of an electrode resulting from the passage of current
polarization
