Question

naturally occurring chlorine that is put in pools is 75.53 percent 35cl (mass = 34.969 amu) and 24.47 percent 37cl (mass = 36.966 amu). calculate the average atomic mass.

Explanation:

Step1: Convert percentages to decimals

$75.53\% = 0.7553$, $24.47\%=0.2447$

Step2: Calculate weighted - average

$$\begin{align*} \text{Average atomic mass}&=(34.969\times0.7553)+(36.966\times0.2447)\\ &=34.969\times0.7553 + 36.966\times0.2447\\ &=26.42 + 9.04\\ &=35.46 \end{align*}$$

Answer:

$35.46$ amu