Bài giải:
Câu 1:
Ta có:$\frac{16.2}{M_R+16.2}=\frac{53,3}{100}$
$⇔\frac{32}{M_R+32}=\frac{53,3}{100}$
$⇔\frac{32}{M_R+32}=0,533$
$⇔32=0,533.(M_R+32)$
$⇔32=0,533.M_R+17,056$
$⇔0,533.M_R=14,944$
$⇔M_R≈28(g/mol)$
⇒ $R$ là nguyên tố Silic ($Si$)
Câu 2:
Ta có: $\frac{M_R}{M_R+1}=\frac{98,765}{100}$
$⇔\frac{M_R}{M_R+1}=0,98765$
$⇔M_R=0,98765.(M_R+1)$
$⇔M_R=0,98765.M_R+0,98765$
$⇔0,012345.M_R=0,98765$
$⇔M_R≈80(g/mol)$
⇒ $R$ là nguyên tố Brôm ($Br$)
