1. Mm NaOH = 40 g / mol Ca(OH)2 = 74 g / mol
g NaOH = 500 g Ca(OH)2 x 1 mol Ca(OH)2 x 2 mol NaOH x 40 g
NaOH
```````````````````` ``````````````````
```````````````` 74 g
Ca(OH)2 1 mol Ca(OH)2 1 mol NaOH
g = 540.
54 de NaOH
2.
Mm Zn3(PO4)2 = 386 g / mol Zn = 65.
38 g / mol
g Zn3(PO4)2 = 10 g Zn x 1 mol Zn x 1 mol Zn3(PO4)2 x 386 g Zn3(PO4)2 `````````````` ```````````````````````` ``````````````````````` 65.
38 g Zn 3 mol Zn 1 mol Zn3(PO4)2
g = 19.
68 g de Zn3(PO4)2
3.
Mm C3H8 = 44 g / mol O2 = 32 g / mol
calcular moles a partir de los gramos
moles C3H8 = 20 g / 44 g / mol = 0.
454 mol
moles O2 = 20 g / 32 g / mol = 0.
625 mol
calcular moles a partir de la reacción
n CO2 = 0.
454 mol C3H8 x 3 mol CO2 ```````````````` 1 mol C3H8
nCO2 = 1.
362 mol
n CO2 = 0.
625 mol O2 x 3 mol CO2 ``````````````` 5 mol O2
n CO2 = 0.
375
Reativo limitante : O2 produce 0.
375 moles de CO2
Calcular reactivo en exceso :
g C3H8 = 20 g O2 x 1 mol O2 x 1 mol C3H8 x 44 g C3H8 `````````````` ```````````````` ``````````````` 32 g O2 5 mol O2 1 mol C3H8
g C3H8 = 5.
5 g
g exceso = 20 g - 5.
5 g = 14.
5 g de C3H8
4.
Mm AlBr3 = 267 g / mol Al = 27 g / mol Br2 = 160 g / mol
1.
Calcular moles a partir de los gramos
moles Al = 25 g / 27 g / mol = 0.
926 mol Al
moles Br2 = 100 g / 160 g / mol = 0.
625 mol
2.
Calcular moles de AlBr3
moles AlBr3 = 0.
926 moles Al x 2 mol AlBr3 `````````````````` 2 mol Al
moles AlBr3 = 0.
926
moles AlBr3 = 0.
625 moles Br2 x 2 mol AlBr3 `````````````````` 3 mol Br2
moles AlBr3 = 0.
416 mol
calcular masa de AlBr3
m = 0.
416 mol x 267 g / mol = 111.
07 g AlBr3
calcular % de rendimiento
% rend.
= 64.
2 g / 111.
07 g x 100
% rend.
= 57.
80 %.