Answer to Question #267867 in General Chemistry for Rei

Question

The percent composition of an unknown substance is 75.42% Carbon, 6.63% Hydrogen, 8.38% Nitrogen, and 9.57% Oxygen. If its molar mass is 334.0 g/mol what is its empirical and molecular formula

Answer 1

C H N O

Mass 75.42 6.63 8.38 9.57

Mole ÷12 ÷1 ÷14 +16

= 6.29 6.63 0.6 0.6

Divide ÷0.6 ÷0.6 0.6 0.6

by sma-

Lest mole

= 10.5 11 1 1

Multiplying through by 2 we have;

C₂₁H₂₂N₂O₂ which is the empirical formula.

For the molecular formula

(C₂₁H₂₂N₂O₂)x =334

(21×12)+(1×22)+(14×2)+(16×2)X=334

(252+22+28+32)X=334

334X=334

X=1

Therefore our molecular formular is;

C₂₁H₂₂N₂O₂