Un hidrocarburo saturado gaseoso esta formado por un 80% de carbono?

1. Calcular % de H

% H = 100% - 80% = 20 % de H

2.

Calcular moles de cada elemento

C : 80 g / 12 g / mol = 6.

67 mol

H : 20 g / 1 g / mol = 20 mol

3.

Dividir entre el menor de los resultados :

C : 6.

67 mol / 6.

67 mol = 1

H : 20 mol / 6.

67 mol = 3

4.

Fórmula empírica : CH3

5.

Calcular Mm FE

C : 1 x 12 = 12 g / mol

H : 3 x 1 = 3 g / mol

``````````````````````````````` Mm = 15 g / mol

6.

Aplicar la ley general de los Gases ya que la fórmula molecular CN

V · P = n · R · T

T = 273 K

P = 1 atm

R = 0.

0821 (L atm / mol K)

n = m / Mm (1) ; d = m / v (2)

sustituir (1) V · P = m / Mm · R · T despejar Mm y V

P · Mm = m / v · R · T sustituir m / v = d

Mm = d · R · T ````````````` P

Calcular Mm del gas

Mm = 1.

34 g / mL · 0.

0821 ( L · atm / mol · K) · 273 K `````````````````````````````````````````````````````````````` 1 atm

Mm = 30.

03 g / mol

7.

Calcular n = Mm compuesto / Mm FE

n = 30 g / mol / 15 g / mol

n = 2

8.

Formula molecula : (CH3)2 = C2H3 / ( CH3 - CH3 ) etano.