Answer:
Abundance for chlorine:
76.9% is 35 Cl and 23.1% is 37 Cl.
Explanation:
the average mass of one mole of chlorine is 35.453g.
Let x be the fraction of the chlorine that is number 35.
1 – x is the fraction that is number 37.
Since they have equal mass number, we equate the two expressions :
34.9689 * x + 36.9659 * (1 – x) = 34.9689 * x + 36.9659 – 36.9659 * x
34.9689 * x + 36.9659 – 36.9659 * x = 35.453
1.997 * x = 1.5359
x = 1.5359 ÷ 1.997
The decimal fraction is approximately 0.769. This means 76.9% is 35 Cl and 23.1% is 37 Cl.
