Question

suppose an element has two naturally occurring isotopes $_{20}^{42}x$ and $_{20}^{45}x$ with atomic masses 42.00 amu and 45.00 amu, respectively. determine the average atomic mass for x given a 6.50% abundance for $_{20}^{42}x$ and a 93.50% abundance for $_{20}^{45}x$. report your answer in amu, but do not include units in your submission on canvas. answer

Explanation:

Step1: Convert percentages to decimals

$6.50\% = 0.065$ and $93.50\%=0.935$

Step2: Use the average - atomic - mass formula

The formula for average atomic mass $A$ is $A = m_1x_1 + m_2x_2$, where $m_1$ and $m_2$ are the atomic masses of the isotopes and $x_1$ and $x_2$ are their respective abundances.
$A=(42.00\times0.065)+(45.00\times0.935)$
$A = 2.73+42.075$

Answer:

$44.805$