Question

Table salt, NaCl(s), and sugar, C12H22O11(s), are accidentally mixed. A 5.50-g sample is burned, and 2.60 g of CO2(g) is produced. What was the mass percentage of the table salt in the mixture?

Answer 1

mass of CO2 = 2.6 g

moles of CO2 = mass / molar mass

                       = 2.6 / 44

                       = 0.0591

moles of C = 0.0591

in one sugar molecule (C12H22O11) has 12 C atoms. so

moles of sugar = 0.0591 / 12

                         = 0.004925

mass of sugar = moles x molar mass of sugar

                        = 0.004925 x 342

                        = 1.68 g

sample mass = 5.50 g

sugar % = (mass of sugar / sample sugar) x 100

              = (1.68 / 5.50 )

              = 30.54%

salt % = 100 - 30.54%

           = 69.45%