Given :
A balanced chemical equation :
[tex]Zn +Cl_2->ZnCl_2[/tex]
To Find :
How many grams of zinc are needed to produce 12 grams of zinc chloride.
Solution :
Moles of [tex]ZnCl_2[/tex] ,
[tex]n=\dfrac{Given \ wt}{Molecular\ Mass}\\\\n =\dfrac{12}{136.30}\ mol\\\\n=0.088\ mol[/tex]
Now, by balanced chemical equation we can say that 1 mol of Zn produce
1 mol of [tex]ZnCl_2[/tex] .
So, 0.088 mol of Zn is required to produced 0.088 mol of [tex]ZnCl_2[/tex] .
[tex]Mass \ required = molecular \ mass \times moles\\\\m = 65.38 \times 0.088\\\\m=5.8 \ gm[/tex]
Therefore, 5.8 grams of zinc is required.
Hence, this is the required solution.