Answer is: a possible identity for the unknown compound is C₃H₈.
m(binary compound) = 10.0 g.
m(H₂O) = 16.3 g; mass of water.
M(O₂) = 32 g/mol; molar mass of oxygen.
M(binary compound) = 1.38 · 32 g/mol.
M(binary compound) = 44.16 g/mol.
n(binary compound) = 10 g ÷ 44.16 g/mol.
n(binary compound) = 0.225 mol; amount of substance.
n(H₂O) = 16.3 g ÷ 18 g/mol.
n(H₂O) = 0.9 mol; amount of water.
m(H₂O) : n(binary compound) = 0.9 mol ÷ 0.225 mol.
m(H₂O) : n(binary compound) = 4 : 1.
Unknown cpmpound has 4 times more hydrogen than water, it has 8 hydrogen atoms.
Second element in compound is carbon:
M(X) = 44.16 g/mol - 8 · 1.01 g/mol.
M(X) = 36.08 g/mol ÷ 3.
M(C) = 12.01 g/mol.
