# The atomic mass of silver found in nature is Ar (Ag) = 107,983. This silver is made of 107Ag and 109Ag Isotopes. Calculate the proportion of mass of 107Ag isotope which is in natural silver atoms?

##### 3 Answers

#### Explanation:

x: 107Ag isotope mass %

100-x: 109Ag isotope mass %

Ar (Ag)=

Ar (Ag)=

#### Explanation:

If **x** is the fraction of Ag107 and **y** is the fraction of Ag109 then we can write:

We can also say:

From

Substitute this value for **x** into

From

In percentages:

50.85%

Similar to the others, but posted by request of Austte.

#### Explanation:

This is basically a ratio math problem. We combine known percentages of have several different masses into a weighted-average mass by multiplying each mass by the weight percent and adding them up. We can use the same equation to work from the weighted average back to the percentages.

With only two isotopes, we also know that

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