n = nr moli = masa subst / M.moleculara
2 moli..... a moli..... b moli..... c moli
Ca + 2HCl => CaCl2 + H2
1........ ... 2.............. 1............... 1
=> a = 2x2/1 = 4 moli HCl,
M HCl = 36,5 g/mol
=> m = 4x36,5 = 146 g HCl
=> b = 2x1/1 = 2 moli CaCl2
M CaCl2 = 111 g/mol
=> m = 2x111 = 222 g CaCl2
=> c = 2x1/1 = 2 moli H2
M H2 = 2 g/mol
=> m = 2x2 = 4 g H2