Question #87de9

1 Answer
Oct 1, 2016

color(red)(C_2H_4O)C2H4O

Explanation:

Atomic mass of H=1" g/mol"H=1 g/mol
Atomic mass of C=12" g/mol"C=12 g/mol
Atomic mass of O=16" g/mol"O=16 g/mol
Molar mass of CO_2=44" g/mol"CO2=44 g/mol
Molar mass of H_2O=18" g/mol"H2O=18 g/mol

Mass of C in 7.59g CO_2=(7.59g)/(44"g/mol")xx12"g/mol"=2.07gCO2=7.59g44g/mol×12g/mol=2.07g

Mass of H in 3.11g H_2O=(3.11g)/(18"g/mol")xx2"g/mol"=0.345gH2O=3.11g18g/mol×2g/mol=0.345g

These two amounts of C and H have been obtained from 3.8g compound containing C ,H and O.

So the remaining (3.80-2.07-0.35)g=1.38g is the mass of Oxygen present in 3.8 g compound.

Hence dividing these masses of elements with respective atomic masses of elements and taking their ratio we get the ratio of number of atoms of C, H and O in the molecule of the compound as below

C:H:O=2.07/12:0.345/1:1.38/16C:H:O=2.0712:0.3451:1.3816
=0.1725:0.345:0.08625=0.1725:0.345:0.08625

=(0.1725/0.08625):(0.345/0.08625):(0.08625/0.08625)=(0.17250.08625):(0.3450.08625):(0.086250.08625)
=2:4:1=2:4:1

Hence empirical formula of the compound is color(red)(C_2H_4O)C2H4O