3) Which pair of formulas represents the empirical formula and molecular
formula for a certain (the same) compound?

A. CH4 and C2H6

B. CH2O and C4H6O

C. O2 and O3

D. C3H403 and C6H8O

The pair of formulas that represents the empirical formula and molecular formula for the same compound is  C₃H₄O₃ and  C₆H₈O₆.

Empirical formula of a chemical compound is the simplest whole number ratio of atoms present in that particular compound. This formula does not represent the total number of atoms present in the compound.

Molecular formula of a chemical compound gives the total number of atoms of each element present in that compound.

From the given options, the pair of formulas that represents the empirical formula and molecular formula for the same compound is:

Learn more about empirical and molecular formulas here: link

The answer to your question is maybe letter D, but the last oxygen needs a number 6.

Explanation:

The empirical formula gives the actual elements that form part of a molecule but not the total numbers.

The molecular formula gives the total number of atoms of each element in a molecule.

We must factor the molecular formula to know if a formula is the empirical formula of that.

A.        CH₄    C₂H₆  =  2(CH₃)       these are not empirical molecular formulas

B.        CH₂O  C₄H₆O                     these are not empirical-molecular formulas      

C.        O₂        O₃                           these are not empirical-molecular formulas

D.        C₃H₄O₃   C₆H₈O                 these are not empirical-molecular formulas

                                                       the last oxygen needs a number 6 to be

                                                       the answer.

answer; i believe the correct answer is (solid gold);

the product of the pressure and volume is also constant