## Chemistry: The Central Science (13th Edition)

$6.02\times10^{22}$ molecules of $CH_3CH_2OH$
initially, it is necessary to calculate the molar mass of the substance. The molar mass is given by: MM($CH_3CH_2OH$) = $(1\times12)+(3\times1)+(1\times12)+(2\times1)+(1\times8)+(1\times1)= 38g/mol$ The number of molecules of 1.0 x 10$^{-6}$ mol of $CH_3CH_2OH$ is found by performing the multiplication below: $(38\times10^{-6} g)\times\frac{1 mol-of-compost}{38g}\times\frac{(6\times10^{22} molecules-of-CH_3CH_2OH)}{1mol-of-compost}$ So, thenumber of molecules of 1.0 x 10$^{-6}$ mol of $CH_3CH_2OH$ is $6,02\times10^{22}$ molecules.