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Revision Quiz Corrosion 1

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1 Revision Quiz Corrosion 1
Define corrosion? Define rusting? 3. What is the cause of rusting? 4. How can the initial stages of rusting be detected? 5. Write the ion electron equations showing what happens when iron rusts. Name the reactions. Corrosion involves the change of the surface of a metal from an element into a compound. Rusting is the special name given to the corrosion of iron. Oxygen and water cause rusting. Also a electrolyte (salt solution) speeds up rusting. Use Ferroxyl indicator will change to blue colour. REDOX REACTION Fe(s)  Fe2+(aq) e Oxidation Fe2+ (aq)  Fe3+(aq) + e Oxidation 2H2O(l) + O2(g) e-  4OH- (aq) Reduction

2 Revision Quiz Corrosion 2
What kind of reaction is corrosion What iron ion is made when iron atoms lose electrons? 3. What is physical protection? 4. Give 5 examples of materials that can be used to cover metals. 5. What colour does ferroxyl indicator change to show rusting is happening? Redox Fe2+ Providing a surface barrier to stop water and oxygen getting to the surface of a metal Paint, varnish, grease, plastic other metals like zinc or tin yellow  blue

3 Revision Quiz Corrosion 3
Metals above iron in the ECS can give electrons to iron to protect it. What is this called? How does this protect iron? 3. Which of the following metals would protect iron? Mg, Al, Zn, Sn, Cu, Ag 4. What is meant by MAZIT metals. 5. What is cathodic protection? Sacrificial corrosion Corrosion is the loss of electrons. If the metal gives electrons to the iron it cant lose electrons! Mg, Al and Zn (all are above Fe in the ECS) A run of metals in the ECS- Magnesium, aluminium, zinc, iron, & tin Connection to negative terminal of battery to get a permanent supply of electrons.

4 Revision Quiz Corrosion 4
What is galvanising? How does this protect iron? (2 different ways) 3. When tin plate is scratched, the iron corrodes more quickly why? 4. What is electroplating? 5. What is meant by chemical protection of iron? Covering iron with zinc. Zinc provides a surface barrier and gives electrons to the iron it cant lose electrons! Tin is below iron in the ECS. Iron gives tin electrons protecting the tin Covering one metal with another. The iron is prevented from rusting by taking electrons from another metal or a battery.


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