Al descomponer 3 gramos de carburo de aluminio con agua caliente se recogen 1, 25 L de metano a 25ºC y 800 mmHg.
Determinar el grado de pureza del carburo de aluminio.
Al4C3 + 12 H2O → 4 Al(OH)3 + 3 CH4 m = Al4C3 = 3 gV = 1.
25 LT = 25 ºC + 273 = 298 KP = 800 mmHg / 760 = 1.
052 atmR = 0.
0821 (L atm / mol K)1.
Calcular moles aplicando la ley e los gases idealesV x P = n x R x Tn = ( 1.
25 L x 1.
052 atm / (0.
0821 (L atm / mol K) x 298 K)n = 0.
0537 moles de metano2.
Calcular moles de AlCl3n Al4C3 = 0.
0537 mol CH4 x 1 mol Al4C3 ``````````````````````````` 3 mol CH4n Al4C3 = 0.
0179 moles3.
Calcular masa de Al4C3Mm Al4C3 = 144 g / molmasa = 0.
0179 mol x 144 g ```````````` 1 molmasa = 2.
577 g de Al4C34.
Calcular la pureza% rend.
= 2. 577 g x 100 ````````````````` 3 g% rend.
= 85.
9 %.