What is the mass, in grams, of 9.57×1024 molecules of methanol (CH3OH)?

Answer 1

Calculate the molar mass of CH₃OH by looking up the atomic mass of each element in the periodic table:

C (carbon) = 12.011 g/mol

H (hydrogen) = 1.008 g/mol but there are 4 H atoms so 1.008 x 4 = 4.032 g/mol

O (oxygen) = 15.999 g/mol

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CH₃OH = 12.011 + 4.032 + 15.999 = 32.042 g/mol

Using Avogadro's Number, which is 6.022 x 10²³ molecules/mole, we can calculate the number of moles in 9.57 x 10²⁴ molecules of CH₃OH:

(9.57 x 10²⁴ molecules)/(6.022 x 10²³ molecules/mole) = 15.891 moles of CH₃OH

Using the molar mass, we can now calculate the mass of 15.891 moles of CH₃OH:

(32.042 g/mol)(15.891 moles) = 509 grams