MCO2 = AC+2AO = 12+2*16 = 44g/mol
MCH4 = AC+4AH = 12+4*1 = 16g/mol
MAl2O3 = 2AAl + 3AO = 2*27+3*16 = 102g/mol
MMg3(PO4)2 = 3AMg + 2(AP+4AO) = 3*24+2(31+4*16) = 262g/mol
M(NH4)2CO3 = 2(AN+4AH) + AC+3AO = 2(14+4*1) +12+3*16 = 96g/mol
a) MH2O = 18g/mol
n = m/M = 36/18 = 2 moli H2O
18g H2O..............1 mol
36g H2O..........x = 2 moli
b) m = 72kg = 7200g H2O
n = m/M = 7200/18 = 400 moli H2O
18g H2O..............1 mol
7200g H2O.......x = 400 moli
