rxn - metals + H20 Flashcards
Metal + water -> metal hydroxide or oxide and H2, do all metals react with water?
nep, some react wid cold, hot or steam, others dont
Metal + cold/hot water -> ?
Metal + cold/hot water -> metal hydroxide + hydrogen
Metal + steam ->
Metal + steam -> metal oxide + hydrogen
How and wid what do sodium and potassium reaxt?
React violently with even cold water.
K + cold H20 -> ? what bout the heat part?
K + H20 -> 2KOH + H2 + Heat, rxn is highly exothermic (heat producing) due to which the hydrogen gas catches fire immediately, hence it is v v reactive
Na + Cold H20? heat?
Na + H20 -> 2NaOH + H2 + Heat rxn is highly exothermic (heat producing) due to which the hydrogen gas catches fire immediately nd causes lil explosions
Ca + Cold H20 -> ? heat?
Ca + H2-> Ca(OH)2 + H2, heat is less not enuf to burn the hydrogen gas, this piece will be floating on water bcs bubbles of hydrogen gas stick to its surface. , it is less violent, it is less reactive than Na
Mg + Hot H20 -> ?
Mg + H20 -> Mg(OH)2 + H2, this piece will be floating on water bcs bubbles of hydrogen gas stick to its surface. Mg is less reactive than Ca.
Mg also reacts rapidly wid steam
Mg + H2O -> MgO + H2 HERE MG OXIDE IS FORMED BCS OF STEAM
Which metals dont react wid hot/cold but wid steam?
Al, Zn, Fe
Al + steam H20 ->
2Al + 3H20 -> Al2 O3 + 3H2, the layer doesnt let it react with water under ordinary conditions
Zn + steam H20
Zn + H20 -> ZNO + H2
Red hot iron
Fe + H20
3FE + 2H20 -> FE3O4 + 4H2
which metals dont react with ny water or steam
Lead, cu, au, ag
How do metals displace hydrogen from water?
H20 is ionized to give -> H+ and OH- ions, when metal + water -> electrons that reduce H+ ions of water to hydrogen atoms, which then form H2. Unreactive ones dont give out electrons easily hence no reduction and no h2 gas
