Modelová Otázka ID 3677 - 
Jaký objem vodíku vznikne při reakci 5 gramů sodíku s nadbytkem vody? Ar(Na) = 23
Správná odpověď je: B
Rovnice reakce sodíku s vodou vypadá takto:
2 Na + 2 H2O → H2 + 2 NaOH.
Výpočet provedeme následovně:
n(Na) = m(Na)/M(Na)
n(H2) = n(Na)/2 = m(Na)/[2 · M(Na)]
V = n(H2) · Vid = [m(Na) · Vid]/[2 · M(Na)]
V = (5 · 22,414)/(2 ·23) = 2,44 l.
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