PTHH: 2A + 3Cl2 \(\rightarrow\)2ACl3
BTKL ta có: mA + mCl2 = mACl3
\(\rightarrow\)\(\text{8,1 + mCl2 = 40,05}\)
\(\rightarrow\)mCl2 = 31,95 (g)
\(\rightarrow\)nCl2 = mCl2 : MCl2 = 31,95 : 71 = 0,45 (mol)
Theo PTHH: nA = \(\frac{2}{3}\).nCl2 = \(\frac{2}{3}\).0,45 = 0,3 (mol)
\(\rightarrow\) MA = mA : nA = 8,1 : 0,3 = 27 (g/mol)
\(\rightarrow\) A là Nhôm (Al)