# Question 5e9c7

Oct 1, 2014

The mass ratio of zinc to iodine is 1 to 3.882.

#### Explanation:

The mass ratio of two elements in a compound is the mass of one element in a given amount of the compound divided by the mass of the other element.

Let's calculate the mass of $\text{Zn}$ in 1 mol ${\text{ZnI}}_{2}$.

$\text{Mass of Zn" = 1 color(red)(cancel(color(black)("mol ZnI"_2))) × (1 color(red)(cancel(color(black)("mol Zn"))))/(1 color(red)(cancel(color(black)("mol ZnI"_2)))) × (65.38 "g Zn")/(1 color(red)(cancel(color(black)("mol Zn")))) = "65.38 g Zn}$

Also, the mass of $\text{I}$ in 1 mol of ${\text{ZnI}}_{2}$ is

$\text{Mass of I" = 1 color(red)(cancel(color(black)("mol ZnI"_2))) × (2 color(red)(cancel(color(black)("mol I"))))/(1 color(red)(cancel(color(black)("mol ZnI"_2)))) × (126.9 "g I")/(1 color(red)(cancel(color(black)("mol I")))) = "253.8 g I}$

$\text{Mass of Zn"/"Mass of I" = "65.38 g"/"253.8 g}$

To get the ratio in its smallest terms, we divide the numerator and the denominator by the smaller number ("65.38 g")#.

Then

$\text{Mass of Zn"/"Mass of I} = \frac{1}{3.882}$