1.according to the metal reactivity series , aluminium is a more reactive metal than iron , why is it resistant to corrosion?
2. a very thin plastic film is often found on the inner surface of soft-drink cans.Explain the function of this plastic film.
3.write balanced equation and briefly describe the observation of the following reaction : lead oxide + carbon
{讀Chem}3條關於metal既問題!!答到有20點
2010-12-30 7:58 am
回答 (2)
2010-12-30 5:00 pm
1.This is because of the nature of the metal oxides . Al2O3 is hard which covers the metal to prevent any further contact of O2 , however iron oxides are loose stuff which makes O2 to continue to react with the metal .
2. Most soft drinks contain cirtic & carbonic acids which can dissolve the AL2O3 away to make the metal corosion . A layer of polymer is coated to withstand such etching .
3. PbO + C ------> Pb + CO + 107 KJ/mole endothermic reaction
2. Most soft drinks contain cirtic & carbonic acids which can dissolve the AL2O3 away to make the metal corosion . A layer of polymer is coated to withstand such etching .
3. PbO + C ------> Pb + CO + 107 KJ/mole endothermic reaction
2010-12-30 8:49 am
答住第一條先，因為aluminium會react with oxygen形成Al2O3，此物質不會因氧化而腐蝕，所以它能抗腐蝕
2010-12-30 00:55:50 補充：
第二條是因為soft drinks可能會跟cans react，可能產生有害物質，而plastic較少和其他物質react，所以它是用來防止soft drink和cans react
(p.s. soft drink多是acidic，易和metal react，產生hydrogen gas和不同種類的salts)
2010-12-30 01:05:23 補充：
第三條︰2PbO+C=2Pb+CO2
from yellow to gray
2010-12-30 00:55:50 補充：
第二條是因為soft drinks可能會跟cans react，可能產生有害物質，而plastic較少和其他物質react，所以它是用來防止soft drink和cans react
(p.s. soft drink多是acidic，易和metal react，產生hydrogen gas和不同種類的salts)
2010-12-30 01:05:23 補充：
第三條︰2PbO+C=2Pb+CO2
from yellow to gray
參考: me
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