\(a)n_{CO_2} = n _C = \dfrac{22}{44} = 0,5 ( mol ) \)
\(\rightarrow n_{H_2O}= \dfrac{18}{18}= 1 ( mol) \)
\(\Rightarrow n_H = n_{H_2O} .2 = 1 . 2 = 2 ( mol ) \)
\(\Rightarrow ∑m_A = m_C + m_H = 8( g) \)
\(b )x : y = n_C : \dfrac{1}{2} n_H = 1 : 2 \)
\(\Rightarrow x = 1 ; y = 2 \)
\( 2y≤2x+2\Rightarrow n = 1 ( thỏamãn ) \)
\(\rightarrow CTPT : CH_4\)