metals pt.1đ¤ Flashcards
define alloys
alloys are a mixture of a metal with one or more other elements
reactivity series of metals
po so ca ma al zi ir ti le (hy) co si go
products of reaction of metals with water/steam
metal oxide + hydrogen gas
which metals can react with water?
po, so, ca, ma (slow)
which metals can react with steam?
zi, ir (slow)
which metals cannot react with water or steam?
al, le, co, si, go
why can aluminium not react with water/steam?
aluminium is covered with a thin layer of non-porous aluminium oxide which adheres strongly to the metal and prevents it from reacting
which metals can react with acids?
po, so, ca, ma, zi, al (unreactive at first, then rapid), ir, le (stops abruptly)
why is aluminium with acid unreactive at first, then rapid?
[aluminium oxide]. however, hydrochloric acid will react with the aluminium oxide to form soluble aluminium chloride and water. once the oxide layer is reacted away, the reaction between acid and metal is rapid
why does lead with acid reaction stop abruptly?
insoluble lead (II) chloride is formed and coats onto the surface of lead metal, preventing further reaction between lead and hydrochloric acid
explain displacement of a metal from metal salt solution (iron nail placed in copper (II) sulfate solution)
iron is more reactive than copper, hence iron loses electrons more readily than copper. iron displaces copper from blue copper (II) sulfate to form reddish-brown copper solid and pale green iron (II) sulfate solution
what is a thermit reaction?
displacement of metal from metal oxide (same explanation as salt solution)
which metals can be reduced by carbon?
from zinc downwards in the reactivity series
which metals can be reduced by hydrogen?
from iron downwards in the reactivity series
why is hydrogen continuously passed into the tube after the experiment?
to prevent air from entering the combustion tube as oxygen will react with the hot metal to form back the metal oxide
