carbon dioxide

[xeriphic]

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i can't remember where it was from but besides carbon dioxide reacting with carbonate to form the precipatate does it also react with H ions, which becomes an acid

can someone clarify

[xeriphic]

also i have some questions about this

provide information about the range of chemical procedures which can be used to clean, stabilise and preserve artefacts from shipwrecks

from above i was wondering where it says clean it means the same as restore right, also are the methods used to clean artefacts from shipwrecks different to those artefacts recovered elsewhere, since it specifically asked about shipwrecks

[xiao1985]

Originally posted by xeriphic
i can't remember where it was from but besides carbon dioxide reacting with carbonate to form the precipatate does it also react with H ions, which becomes an acid

can someone clarify

uhm, i assume you mean react with water???

then yes, co2 dissolve in water to form an equilibrium to form carbonic acid h2co3, a weak acid..

Originally posted by xeriphic
also i have some questions about this

provide information about the range of chemical procedures which can be used to clean, stabilise and preserve artefacts from shipwrecks

from above i was wondering where it says clean it means the same as restore right, also are the methods used to clean artefacts from shipwrecks different to those artefacts recovered elsewhere, since it specifically asked about shipwrecks

my interpretation is: both clean and stablizing would be refering to the restoration of the artefact... artefacts from shipwrecks would contain a high level of ions... so care must be taken - eg, not leavin it on the dock or it will crack etc etc....

[xeriphic]

thanks for clarifying that up, wasn't sure what i'm writting is correct

also i am not sure about these two sentences

"for iron objects dilute sodium hydroxide solution is generally used instead of pure water in the process of leaching: it speeds up the removal of chloride because it converts iron chloride to iron hydroxide which release chloride"

then it says a paragraph down

"it is very difficult to remove chloride from iron by leaching, it appears that considerable amounts of chloride are present as insoluble hydroxy chlorides such as Fe(OH)Cl trapped in Fe(OH)2 and Fe2O3.xH2O deposits"

my question is, so for iron objects is the process of leaching actually valid, also how does it actually occur

i summerised both sentences and came up with this

The method of leaching can also be used for the removal of chloride from iron where pure water is replaced with dilute sodium hydroxide solution. This speeds up the process as FeCl2 converts into Fe(OH)2 and releases chloride. However considerable amounts of chloride are present as insoluble hydroxy chlorides such as Fe(OH)Cl trapped in Fe(OH)2 and Fe2O3.xH2O deposits which may not be totally removed causing further corrosion

^ is the above right, i am not sure