Question #d3fd1

1 Answer
Jun 14, 2017

Answer:

The molecular formula of #"C"_2"H"_5"# is #color(blue)("C"_4"H"_10"#.

The molecular formula of #"CH"# is #color(blue)("C"_6"H"_6#.

Explanation:

In order to determine the molecular formula from an empirical formula, first determine the empirical formula mass. Then divide the given molecular mass by the empirical formula mass.

#color(blue)("Empirical Formula Mass of C"_2"H"_5"#.

#"C":##(2xx12"g/mol")="24 g/mol"#

#"H":##(5xx1"g/mol")="5 g/mol"#

Formula Mass = #"24 + 5 g/mol = 29 g/mol"#

#color(blue)("Molecular Formula of C"_2"H"_5"#

Divide the molecular mass by the empirical mass.

#58/29=2#

Multiply the subscripts in the empirical formula by #2# to get the molecular formula.

#"C"_4"H"_10#

#color(blue)("Empirical Formula Mass of CH"#.

#"C":##1xx12"g/mol"#

#"H":##1xx1"g/mol"#

Formula Mass = #"12 g/mol+1 g/mol=13 g/mol"#

Divide the molecular mass by the empirical mass.

#78/13=6#

#color(blue)("Molecular Formula of CH"#.

Multiply the subscripts of #"CH"# by #6#.

#"C"_6"H"_6"#