1.
m g 525g
3Mg + Al2O3 --> 3MgO + 2Al
3x24 102
=> m = 370,6 g Mg
2.
4 moli N molecule
Na2CO3 + 2HCl --> 2NaCl + H2O + CO2
1 6,022x10la23
=> N = 4x6,022x10la23/1 = 2,409x10la24 molecule CO2
3.
md g 800g
2Fe(OH)3 + 3H2SO4 --> Fe2(SO4)3 + 6H2O
3x98 400
=> md = 3x98x800/400
= 588 g H2SO4
c% = mdx100/ms
=> ms = mdx100/c%
= 588x100/49 = 1200 g sol H2SO4