Respuestas
13.
Si 4,6 g de sodio se dejan reaccionar con 7,5 g de cloro. ¿Cuánto cloruro de sodio se forma?
2 Na + Cl2 → 2NaCl
1. Calcular moles ( n= m/Mm)
n Na = 4.6 g / 23 g/mol = 0.2 mol
n Cl2 = 7.5 g / 35.45 g/mol = 0.21 mol
2. Calcular moles a partir de los calculados
n NaCl = 0.2 mol Na x ( 2 mol NaCl/ 2 mol Na) = 0.2 mol
n NaCl = 0.21 mol Cl2 x ( 2 mol NaCl/ 1 mol Cl2) 0.42 mol
3. Reactivo limitante: Na (produce 0.2 mol de NaCl
4. Calcular gramos de NaCl
m = 0.2 mol x 58.45 g/mol = 11.69 g de NaCl
14.
¿Qué masa y cantidad de sulfuro de cobre se obtiene al hacer reaccionar 64 g de azufre con la cantidad adecuada de cobre?
Cu + S → CuS (sulfuro cúprico)
Mm CuS = 95.61 g/mol
S = 32 g/mol
Cu = 63.54 g/mol
1. calcular moles de CuS
mol CuS = 64 g S x 1 mol S x 1mol CuS
```````````` ``````````````
32 g S 1mol S
mol CuS = 2
g CuS = 64 g S x 1 mol S x 1mol CuS x 95.61 g CuS
```````````` `````````````` ``````````````````
32 g S 1mol S 1 mol CuS
g CuS = 191.22
`````````````````````````````````````````````````````````````````````````````````````````````````
2Cu + S → Cu2S (sulfuro cuproso)
Mm = Cu2S = 159.15 g/mol
1. calcular moles de CuS
mol CuS = 64 g S x 1 mol S x 1 mol CuS
```````````` `````````````` ````
32 g S 1 mol S
mol CuS = 2
g CuS = 64 g S x 1 mol S x 1 mol Cu2S x 159.15 g Cu2S
```````````` ```````````````````` ````````````````````````````
32 g S 1 mol S 1 mol Cu2S
g CuS = 318.3
15.
a) ajusta la ecuacion química: Bi2S3 + 9/2 O2 → Bi2O3 + 3 SO2
b) calcula la masa de dióxido de azufre que se obtiene al reaccionar 1 Kg de Bi2S3 con la cantidad suficiente de O2
1. convertir Kg a g
m = 1 x 1000 = 1000 g
2. Mm Bi2S3 = 514,16 g/mol
SO2 = 64 g/mol
O2 = 32 g/mol
g SO2 = 1000 g Bi2S3 x 1 mol Bi2S3 x 3 mol SO2 x 64 g SO2
````````````````````` ````````````````````` ```````````````````
514.16 g Bi2S3 1 mol Bi2S3 1 mol SO2
g SO2 = 373.42
c) calcula la masa de oxigeno que reacciona completamente con 5 mol de Bi2S3
g O2 = 5 mol Bi2S3 x 9 ml O2 x 32 g O2
```````````````` `````````````````
2 mol Bi2S3 1 mol O2
g O2 = 720