Question

Styrene, the building block of polystyrene, consists of only empirical formula of styrene? and H. 10.401 g of styrene is burned in oxygen and produces 1.355 g of CO, and 0.278 of H, O, what is the TA Empirical formula

Answer 1

let in compound number of moles of C and H be x and y respectively

Number of moles of CO2 = mass of CO2 / molar mass CO2
= 1.355/44
= 3.08*10^-2

Number of moles of H2O = mass of H2O / molar mass H2O
= 0.278/18
= 1.544*10^-2

Since 1 mol of CO2 has 1 mol of C
Number of moles of C in CO2= 3.08*10^-2
so, x = 3.08*10^-2

Since 1 mol of H2O has 2 mol of H
Number of moles of H = 2*1.544*10^-2 = 3.089*10^-2

Divide by smallest to get simplest whole number ratio:
C: 3.08*10^-2/3.08*10^-2 = 1
H: 3.089*10^-2/3.08*10^-2 = 1


So empirical formula is:CH
Answer: CH