Question

Isobutyl propionate is the substance that provides the flavor for rum extract. combustion of a 1.152 g sample of this carbon-hydrogen-oxygen compound yields 2.726 g co2 and 1.116 g h2o. what is the empirical formula of isobutyl propionate?

Answer 1

Answer;

C7H14O2

Solution;

Isobutyl contains , oxygen, carbon and hydrogen (total mass is 1.152 g)

Mass of carbon = 12/44 × 2.726 g

                           = 0.743455 g

Mass of Hydrogen  = 2/18 × 1.116 g

                            =  0.124 g

Mass of oxygen = 1.152 - (0.7435 + 0.124)

                           =  0.2845 g

Moles of carbon ;  0.7435/12 = 0.06196 moles

Moles of hydrogen; 0.124/1 = 0.124 moles

Moles of oxygen;  0.2845/16 = 0.01778 moles

Ratios ; 0.06196/0.01778 ; 0.124/0.01778 : 0.01778/0.01778

         =  3.5 :  7.0 : 1

To make them whole numbers ; we multiply the ratios by 2  to get;

(3.5 :  7.0 : 1 )2 = 7 : 14 : 2

Thus, the empirical formula of Isobutyl propionate  is C7H14O2