Question

En la reacción del hidróxido de magnesio con el ácido clorhídrico se produce cloruro de magnesio y agua.

Si utilizamos 250 gracias de hidróxido de magnesio y 150 gracias de ácido clorhídrico ¿Cuánto cloruro de magnesio y que cantidad de agua se obtiene?

Answer 1

             Mg(OH)2 + 2HCl → MgCl2 + 2H2O

Mm Mg(OH)2 = 58.32 g/mol
            MgCl2 = 95.21 g/mol
                HCl = 36.46 g/mol

1. calcular moles

n = 250 g Mg(OH)2 x 1 mol Mg(OH)2
                                  ``````````````````````
                                     58.32 g/mol

n = 4.287 moles Mg(OH)2

n = 150 g HCl  x  1 mol HCl
                          `````````````````
                           36.46 g HCl

n = 4.114 moles HCl

2. calcular moles de MgCl2 a  partir de los moles calculados

n MgCl2 = 4.287 moles Mg(OH)2  x  1 mol MgCl2
                                                          ``````````````````
                                                          1 mol Mg(OH)2

n MgCl2 = 4.287

n MgCl2 = 4.114 moles HCl  x  1 mol MgCl2
                                                ````````````````````
                                                  2 moles HCl

n MgCl2 = 2.057 moles

REACTIVO LIMITANTE: HCl (produce 2.057 moles de MgCl2)

3. calcular gramos de MgCl2

g = 2.057 moles MgCl2  x  95.21 g MgCl2
                                           ````````````````````
                                             1 mol MgCl2

g = 195.84 de MgCl2

4. g de H2O

g H2O = 2.057  mol  MgCl2 x  2 mol H2O x     18 g H2O
                                                ``````````````       ```````````````
                                                 1 mol MgCl2    1 mol H2O

g H2O = 74.05