Chlorine occurs naturally as two isotopes with masses and

CHEMISTRY · Single correct · A Level · Chemistry · Atomic structure · Atomic structure

Problem

Chlorine occurs naturally as two isotopes with masses

34.97\,\text{amu}

and

36.97\,\text{amu}

. If

x

represents the fractional abundance of the lighter isotope, which expression correctly relates

x

to the tabulated average atomic mass of chlorine,

35.45\,\text{amu}

? (a)

34.97x+36.97x=35.45

(b)

34.97(1-x)+36.97x=35.45

(c)

34.97x+36.97(1-x)=35.45

(d)

\dfrac{34.97x+36.97(100-x)}{100}=35.45