Shipwrecks (1 Viewer)

[SoCal]

Someone please say that zinc is a passivating metal.

 

[Vana]

DAYUM!! i thought the copper would corrode less because its less reactive compared to aluminium!

 

[~TeLEpAtHeTiC~]

for that question i said aluminium would be best container oxidising to privde apssivating impermeable layer so as to discontinue any corrosion occuring and preventing the promotion of it
said plastic was 2nd best however it is stil permeable and allows for oxygen to enter the vessel and can could a moist warm environment in side it which would promote corrosion as well as differential aeration
finally i said the copper would be the worst becuas of its position on the electrochemical series in respect to iron, causing the copper to act as the cathode, corroding iron which becomes the anode, becuase ths steel contains carbon these impurities provide a surface on which galvanic cells can be formed and corrision/rusting can occur and is further promoted etc et blah blah i think i'm right, anyone disagree?

 

[tegs]

Pretty right.
I actually said that although the aluminium would be good for stopping corrosion on the hooks it wouldn't be much better than the plastic, and due to the corrosion, the aluminium the box would be weakened so that would be a bad choice.

 

[beeflatt]

Last q.

As far as I could gather from the last question, they were basically asking you to talk about Galvani etc. without actually asking it. I mean, the historical understanding part of the question to me meant that they wanted you to bring them into it somehow. It was a six marker after all, and I doubt that they wanted six points on how you used electrolysis if the question asked about the historical understanding. But that's just what I read, and I have a knack for misinterpreting these things, particularly in chemistry and biology papers.

 

[Carla2003]

so the aluminium after forming the layer doesn't act as the cathode in the same way as copper?

 

[hipsta_jess]

the aluminium acts as a passivating metal, which means it forms a thick non-prous layer over the base metal, stopping corrosion of the base metal.
so no, the Al doesnt act like the Cu cathode

 

[manta]

Originally posted by hipsta_jess
for the container one, i wrote heaps, but my basic answer was:
Cu-would not work, the Fe would still corrode more
Al-would be good if the fishermen didnt mind an Al oxide on their hooks, which could be easily removed
Plastic-provided the hooks were clean and dry when they went into the container, and as much air as possible was excluded, it would work in slowing down the corrosion, but wouldnt actually stop it or anything, there was no chemical anti-corrosion techniques in plastic

yeah thats pretty much what I wrote, expended it a lot though... I luved that question! I wrote like three pages on it alone, the last one was a bit basic, but overall the option was good i thought!