Reactivity
exercises |
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Most food is stored
on the supermarket shelves in tin coated iron containers. Tin is not a
very reactive metal and will not rust in the presence of oxygen. The iron
is totally covered with tin in order to protect it from rusting. If the
tin is scratched and the iron exposed the iron rusts very quickly. Explain
why? |
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Aluminium is a very reactive metal. It reacts with water to produce hydrogen gas in a similar way to sodium. The reason why we can make cooking pots out of aluminium is the fact that aluminium oxide (aluminium rust) forms an impenetrable layer. Unlike iron rust, that flakes off to expose more iron, aluminium rust forms abarrier protecting the aluminium from the oxygen. Salt water tends to break apart the aluminium rust layer. A sea side holiday house was built very close to the ocean. Explain why an aluminium window frame secured to the wood with iron nails fell off the support. |
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