Write the molecular formula, the semideveloped formula and name the linear alkanes of 20, 30, 40, 50 and 100 carbons.
Solution
♣ The 20-carbon alkane is called Eicos ano , its molecular formula is C 20 H 42 , (all alkanes respond to the formula C n H 2n+2 ). In the semi-developed formula, the methyls at the ends are written and the number of CH 2 that the alkane possesses is indicated in parentheses, CH 3
( CH 2 ) 18 CH 3 ♣ The 30-carbon alkane is called Triacontane . Molecular formula: C 30 H 62 . Semi-developed formula: CH 3 (CH 2 ) 28 CH 3 .
♣ With 40 carbons : Tetracontano . Molecular formula: C 40 H 82 . developed formula: CH 3 (CH 2 ) 38 CH 3
♣ With 50 carbons: Pentacontane . Molecular formula: C 50 H 102 . - developed formula: CH 3 (CH 2 ) 48 CH 3
♣ The alkane of 100 carbons is called Hectane
