Respuestas
CALCULA LA COMPOSICION PORCENTUAL DE MgO:
Calcular Mm
Mg: 1 x 24 = 24 g/mol
O: 1 x 16 = 16 g/mol
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Mm = 40 g/mol
% Magnesio
40 g ------ 100 %
24 g ------ x
x = 60 % Mg
% oxigeno
40 g ---- 100 %
16 g ----- x
x = 40 % O
CALCULA LA COMPOSICION PORCENTUAL DE Fe2O3:
Fe: 2 x 56 = 112 g/mol
O:3 x 16 = 48 g/mol
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Mm = 160 g/mol
% Fe
160 g ---- 100 %
112 g ---- x
x = 70 % Fe
% O
160 g ---- 100 %
48 g ---- x
x = 30 % O
CALCULA LA COMPOSICION PORCENTUAL DE Na2SO4:
Na: 2 x 23 = 46 g/mol
S: 1 x 32 = 32 g/mol
O: 4 x 16 = 64 g/mol
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Mm = 142 g/mol
% Na
142 g ---- 100 %
46 g ---- x
x = 32.39 % Na
% S
142 g ---- 100 %
32 g ---- x
x = 22.53 % S
% O
142 g --- 100 %
64 g ---- x
x = 45.07 % O
Respuesta:
4. Calcule la composición porcentual de los siguientes compuestos:
(a) MgO
(b) Fe2O3
(c) Na2SO4
--C: 37.51g/ 12 g/mol = 3.126 moles
H: 4.20 g/ 1 g/mol = 4.20 moles
O: 58.29 g/ 16 g/mol = 3.643 moles
2 dividir entre el menor de los resultados
C: 3.126 moles / 3.1258 moles = 1 x 6= 6
H: 4.20 moles / 3.1258 moles = 1.344 x 6 = 8
O: 3.643 moles / 3.1258 mole = 1.165 x 6 = 7
3. multiplicar por 6 se encuentran resultados con decimales
4. FE: C6H8O7
5. calcular Mm FE
C: 6 x 12 = 72 g/mol
H: 8 x 1 = 8 g/mol
O: 7 x 16 = 112 g/mol
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Mm = 192 g/mol
6. calcular n = Mm compuesto/Mm FE
n = 192.13 g/mol / 192 g/mol
n = 1
7. FM: (C6H8O7)1 = C6H8O7
Calcular %
a. MgO
Calcular Mm
Mg: 1 x 24 = 24 g/mol
O: 1 x 16 = 16 g/mol
```````````````````````````````
Mm = 40 g/mol
% Magnesio
40 g ------ 100 %
24 g ------ x
x = 60 % Mg
% oxigeno
40 g ---- 100 %
16 g ----- x
x = 40 % O
b. Fe2O3
Fe: 2 x 56 = 112 g/mol
O:3 x 16 = 48 g/mol
`````````````````````````````````
Mm = 160 g/mol
% Fe
160 g ---- 100 %
112 g ---- x
x = 70 % Fe
% O
160 g ---- 100 %
48 g ---- x
x = 30 % O
c. Na2SO4
Na: 2 x 23 = 46 g/mol
S: 1 x 32 = 32 g/mol
O: 4 x 16 = 64 g/mol
`````````````````````````````````
Mm = 142 g/mol
% Na
142 g ---- 100 %
46 g ---- x
x = 32.39 % Na
% S
142 g ---- 100 %
32 g ---- x
x = 22.53 % S
% O
142 g --- 100 %
64 g ---- x
x = 45.07 % O
Explicación: