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16 Cards in this Set
- Front
- Back
What is corrosion?
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The chemical or electrochemical deterioration of a material or its properties due to its chemical reaction with the surrounding environment |
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Why does corrosion occur?
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This chemical reaction occurs because of the tendency of metals to return to their naturally occurring state, usually oxide or sulfide ores |
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What is the most common type of corrosion?
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Electrochemical corrosion |
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DEFINE: Atom |
The smallest unit of an element, made up of a positively charged nucleus surrounded by a system of negatively charged electrons |
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DEFINE: Electron |
A negatively charged subatomic particle |
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When does an electric current occur? |
When electrons are forced to move through metal conductors |
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Do electrons flow through liquid solutions?
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Only in the presence of ions |
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DEFINE: Ion |
An atom or group of atoms or molecules which has acquired a net electric charge by gaining or losing electrons |
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What happens when ions are forced to move through liquid solutions?
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An electric current can occur |
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Can ions move through metal conductors? |
No |
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DEFINE: Electrolyte |
Example: Sea water is an electrolyte: an aqueous solution whose major components are sodium and chloride ions |
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DEFINE: Electrochemistry |
The branch of science concerned with chemical reactions at surfaces in contact with electrolytes |
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TRUE OR FALSE:
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TRUE |
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What are the four conditions necessary for metal corrosion to occur? |
1. A metal which has a tendency to corrode (the anode) 2. A dissimilar conductive metal (the cathode) 3. A conductive liquid (electrolyte) must connect the anode and cathode 4. Electrical contact between the anode and cathode must exist (usually metal-to-metal) |
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How can corrosion be stopped or slowed?
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For example: painting a metal surface prevents the electrolyte from connecting the anode and cathode) |
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The corrosion reaction in sea water is accelerated by a factor of what?
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1000 or more |