M,SnO= 135g/mol
M,SnO2=151 g/mol
calculez masa de oxigen din masa data de SnO
135g Sn0............16gO
40,5g.....................x=4,8gO
calculez masa de SnO2 care contine 4,8gO
151gSnO2..........................32gO
X..........................................4,8g
calculeaza x !!!!!!