which of the following is an empirical formula A.C2H5 B.C2H8 C.CH4 D.C4H10

Answer 1

When asked a question like this, think about the definition of empirical formula. Empirical formula is the 'simplest (or smallest) whole number ratio of atoms present in a compound', where as a molecular formula is the 'actual whole number ratio of elements.'

In the future, when you calculate the empirical formula and try to find the molecular formula, you will multiply the empirical formula by positive integer, and each atom will be multiplied by this coefficient to generate the molecular formula.

Now apply this idea to your question. Which molecule is in the smallest whole number ratio?

a. C₂H₅ : empirical formula, because both 2 and 5 do not have a factor in common other than 1; therefore this molecule is the smallest whole number ratio.

b. C₂H₈: molecular formula, because both 2 and 8 have a common factor of 2; therefore the empirical formula would have been CH_4.

c. CH₄: empirical formula

d. C₄H₁₀: molecular formula