The average atomic mass of a sample of an element x is 16.2 u. What are the percentages of isotopes 168x and 188x in the sample?
Answers
Lets take the percentage of the isotope of 16 8 X as --> x %
So , the percentage of the isotope of 18 8X ---> (100 - x) %
We are given the average atomic mass as 16.2
\frac{x}{100} × 16 + \frac{(100 - x)}{100} × 18 = 16.2
\frac{16x}{100} + \frac{1800 - 18 x}{100} = 16.2
\frac{16x + 1800 - 18 x}{100} = 16.2
\frac{-2x + 1800}{100} = 16.2
-2x + 1800 = 16.2 × 100
-2x + 1800 = 1620
-2x = 1620 - 1800
-2x = -180
x = \frac{-180}{-2}
x = 90 %
Therefore , percentage of isotope of 16 8 X = 90 %
percentage of isotope of 18 8 X = 100 - x = 100 - 90 = 10 %
Answer:
Explanation:
the percentage of the isotope of 16 8 X as --> x %
the percentage of the isotope of 18 8X ---> (100 - x) %
We are given the average atomic mass as 16.2
\frac{x}{100} × 16 + \frac{(100 - x)}{100} × 18 = 16.2
\frac{16x}{100} + \frac{1800 - 18 x}{100} = 16.2
\frac{16x + 1800 - 18 x}{100} = 16.2
\frac{-2x + 1800}{100} = 16.2
-2x + 1800 = 16.2 × 100
-2x + 1800 = 1620
-2x = 1620 - 1800
-2x = -180
x = \frac{-180}{-2}
x = 90 %
Therefore , percentage of isotope of 16 8 X = 90 %
percentage of isotope of 18 8 X = 100 - x = 100 - 90 = 10 %