Answer :
The percent zinc in the original mixture is 43.35 %
Steps of evaluation :
The two balanced chemical equations are :
[tex]Zn_{(s)} + 2HCl_{aq}[/tex] → [tex]ZnCl_{2} + H_{2}[/tex]
[tex]Mg_{(s)} + 2HCl_{aq}[/tex] → [tex]MgCl_{2} + H_{2}[/tex]
Step 2 :
Solve for the moles of [tex]H_{2}[/tex] produced :
1.242 g[tex]H_{2}[/tex] ×[tex]\frac{1 mol H_{2} }{2.016g H_{2} }[/tex] = 0.608 mol[tex]H_{2}[/tex]
Step 3 :
If we let x = mass of Zn
Then, 20- x = mass of magnesium
Step 4 :
The moles of [tex]H_{2}[/tex] is equal to the sum of moles of Zn and Mg :
0.608 mol = [tex]\frac{x g Zn}{65.38 g/mol} + \frac{20 - x g Mg}{24.31 g / mol} \\[/tex]
951.56 = - (41.07) x + 1307.6
-356.04 = -(41.07) x
x = [tex]\frac{356.04}{41.07} = 8.67 g Zn[/tex]
Step 5 :
Solve for the mass of Zn = [tex]\frac{Mass of Zn}{Total mass}[/tex] × 100%
= [tex]\frac{8.67}{20}[/tex]× 100 %
= 43.35 %
What is zinc compound used for?
Zinc is mainly used as a protective coating for iron and steel (galvanizing). It is further used for the production of zinc alloys (e.g. brass), rolled zinc, zinc dust (a pigment and a reducing agent), and zinc compounds (e.g. zinc oxide). Zinc oxide is the industrially most important zinc compound.
What kind of mixture is zinc?
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-grayish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table.
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