Asample of an unknown compound has a percent composition of 52.14% carbon, 13.13% hydrogen, and 34.73% oxygen. which compounds could the sample be?

                The two possible compounds are;

                            1) Dimethyl Ether H₃C--O--CH₃

                           2) Ethanol  H₃C--CH₂--OH

Step 1: Calculate Moles of each Element;

                      Moles of C  =  %C ÷ At.Mass of C

                      Moles of C  =  52.14 ÷ 12.01

                      Moles of C  =  4.341 mol

                      Moles of H  =  %H ÷ At.Mass of H

                      Moles of H  =  13.13 ÷ 1.01

                      Moles of H  =  13.00 mol

                      Moles of O  =  %O ÷ At.Mass of O

                      Moles of O  =  34.73 ÷ 16.0

                      Moles of O  =  2.170 mol

Step 2: Find out mole ratio and simplify it;

                C                                        H                                     O

            4.341                                 13.00                              2.170

     4.341/2.170                      13.00/2.170                    2.170/2.170

               2                                      5.99                                    1

               2                                        6                                       1

Hence,  Empirical Formula  =  C₂H₆O

         As the molecular mass of compound is not given therefore, we can assume and guess the empirical formula to be the molecular formula. Hence, possible compounds are,

                            1) Dimethyl Ether H₃C--O--CH₃

                           2) Ethanol  H₃C--CH₂--OH

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.