Question

La densidad de un gas es 0.054 g/ ml a 988 torr y 30°c ¿cuál es su peso molecular? .

Answer 1

Fórmulas:

P x V = n x R x T (Ley de los gases Ideales)  (a)

D = m/v   (b)

n (moles) = masa/Mm  (c)

R = 0.082 (L atm/ mol K)

d = 0.054 g/mL

T = 30 + 273 = 303 K

P = 988 / 760 = 1.3 atm

1. convertir g/mL  a  g/L

d = 0.054 g  x   1000 mL
     ````````````    ``````````````
        1 mL           1 L

d = 54 g/L

2. sustituir en la fórmula (a)  los moles

P · V =   m  · R ·  T
             ````
             Mm

Mm · P · V = m · R · T   

Mm =  m  · R · T         entonces: m/v = d se sustituye
           `````````````
              V  ·  P

Mm = d ·R · T
          ``````````
               P

Mm = 54 g/L  · 0.082  (L atm / mol K ) · 303 K
          ``````````````````````````````````````````````````````
                             1.3 atm

Mm = 1032.06 g/mol