Đáp án:
a/ MgCO3
MgCO3 có PTK: 24+12+3.16 = 84 đvC
% mMg = $\frac{24}{84}$ . 100 = 28,57%
% mC = $\frac{12}{84}$ . 100 = 14,29%
% mO = $\frac{3.16}{84}$ . 100 = 57,14%
b/ Fe2(SO4)3
Fe2(SO4)3 có PTK: 2.56+3.(32+4.16) = 400 đvC
% mFe = $\frac{2.56}{400}$ . 100 = 28%
% mS = $\frac{3.32}{400}$ . 100 = 24%
% mO = $\frac{3.4.16}{400}$ . 100 = 48%
c/ Al(OH)3
Al(OH)3 có PTK: 27+3.(16+1) = 78 đvC
% mAl = $\frac{27}{78}$ . 100 = 34,62%
% mO = $\frac{3.16}{78}$ . 100 = 61,54%
% mH = $\frac{3.1}{78}$ . 100 = 3,84%
