Question

type the correct answer in the box. round your answer to the nearest hundredth. element x has two isotopes. the table gives information about these isotopes.

isotope	atomic mass (amu)	abundance (%)
x-65	64.9278	30.85

the average atomic mass of element x is □ amu

Explanation:

Step1: Calculate contribution of X-63

Multiply atomic mass of X-63 by its abundance (in decimal).
$62.9296 \times \frac{69.15}{100} = 62.9296 \times 0.6915$
$62.9296 \times 0.6915 \approx 43.515$

Step2: Calculate contribution of X-65

Multiply atomic mass of X-65 by its abundance (in decimal).
$64.9278 \times \frac{30.85}{100} = 64.9278 \times 0.3085$
$64.9278 \times 0.3085 \approx 20.030$

Step3: Sum the contributions

Add the two contributions to get average atomic mass.
$43.515 + 20.030 = 63.545$

Step4: Round to nearest hundredth

$63.545$ rounded to nearest hundredth is $63.55$ (since the thousandth digit is 5, we round up the hundredth digit).

Answer:

63.55