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zBret
Yeah, it should read "hot-wheels dragsters" instead......ChFalkensteiner wrote: Interestingly it appears to be an early printing with the mention of "Hotwheels dragsters" on the back page - I had understood that bit to have been changed for full production.
Lime is made by heating limestone, calcium carbonate, to drive off carbon dioxide, leaving behind calcium oxide. When this lime, the calcium oxide, is exposed to water, a process known as slaking, it hydrates and forms calcium hydroxide which is strongly alkaline. Unfortunately, zinc is an amphoteric metal, meaning that it will dissolve in both acids and alkalis. In this case, the zinc in contact with calcium hydroxide will oxidise to calcium zincate, a reaction paired with the evolution of hydrogen.Malibu wrote:Hi,
can anyone explain what is ment by "it was found out that zinc, when in contact with the lime in plaster, would corrode..."
This sentence can be found on page No.8 of Nick´s book.
Thanks
Stephan
Thanks for your explanation Idreis but I still have not understood what plaster is and how zinc, plaster and lime come together.Idris wrote:Lime is made by heating limestone, calcium carbonate, to drive off carbon dioxide, leaving behind calcium oxide. When this lime, the calcium oxide, is exposed to water, a process known as slaking, it hydrates and forms calcium hydroxide which is strongly alkaline. Unfortunately, zinc is an amphoteric metal, meaning that it will dissolve in both acids and alkalis. In this case, the zinc in contact with calcium hydroxide will oxidise to calcium zincate, a reaction paired with the evolution of hydrogen.
Plaster is the coating put on internal walls in order to give them a smooth finish. The lime (in slaked form) is part of the plaster. Presumably the issue was that some of the tooling was stored in contact with the walls. It may also have been that the plasterwork was not in good condition, resulting in plaster crumbling onto the tooling.Malibu wrote:Thanks for your explanation Idreis but I still have not understood what plaster is and how zinc, plaster and lime come together.Idris wrote:Lime is made by heating limestone, calcium carbonate, to drive off carbon dioxide, leaving behind calcium oxide. When this lime, the calcium oxide, is exposed to water, a process known as slaking, it hydrates and forms calcium hydroxide which is strongly alkaline. Unfortunately, zinc is an amphoteric metal, meaning that it will dissolve in both acids and alkalis. In this case, the zinc in contact with calcium hydroxide will oxidise to calcium zincate, a reaction paired with the evolution of hydrogen.
Stephan