Question

помогите пожалуйста.

Answer 1

$MgCO_{3} = MgO +CO_{2}$   (не нужно)
$4Al + 3O_{2} = 2Al_{2}O_{3}$
$Fe_{2}O_{3} + 3H_{2} = 2Fe + 3H_{2}O$
$2NaOH +H_{2}SO_{4} = Na_{2}SO_{4} + 2H_{2}O$

4.
$Zn + 2HCl = ZnCl_{2} + H_{2}$

$H_{2}O + K = KOH + H_{2}$
$4P + 5O_{2} = 2P_{2}O_{5}$
$2HgO = 2Hg + O_{2}$