Question

URGENT!! Calculati masa procentuala a urmatoarelor substante: CaCo3, CaO, Ch4, MgCl2,

Answer 1

M=masa molară
A(..)=masa atomica

CaCO3
M=A(Ca)+A(C)+3A(O)
M=108g/mol

108g CaCO3.........40g Ca.......12g C.......48g O
100g CaCO3.........X g Ca.........Y g C.......Z g O
=>X=37,03% Ca. Y=11,11% C. Z=51,86% O

CaO
M=A(Ca)+A(O)
M=56g/mol

56g CaO..........40g Ca ........16g O
100g CaO........X g Ca. ........Y g O
=>X=71,42% Ca. Y=28,58% O

CH4
M=A(C)+4A(H)
M=16g/mol

16g CH4.........12g C.......4g H
100g CH4......X g C.......Y g H
=>X=75% C. Y=25% H

MgCl2
M=A(Mg)+2A(Cl)
M=95g/mol

95g MgCl2........24g Mg.......71g Cl
100g MgCl2.......X g Mg.......Y g Cl
=>X=25,26% Mg. Y=74,74% Cl