Question

1. select the answer from the menu. the natural - isotope abundance of copper is shown on the table. isotope percent abundance copper - 63 69.2% copper - 65 30.8% the average atomic mass of copper is - choose the correct answer - amu. 63.1 63.6 64.0 64.4

Explanation:

Step1: Recall average - atomic - mass formula

The formula for the average atomic mass of an element with two isotopes is $A = m_1x_1 + m_2x_2$, where $A$ is the average atomic mass, $m_1$ and $m_2$ are the masses of the isotopes, and $x_1$ and $x_2$ are their fractional abundances. Copper - 63 has a mass of 63 amu and an abundance of $x_1=0.692$, and copper - 65 has a mass of 65 amu and an abundance of $x_2 = 0.308$.

Step2: Calculate the average atomic mass

$A=(63\times0.692)+(65\times0.308)$
$A = 63\times0.692=43.596$ and $65\times0.308 = 20.02$
$A=43.596 + 20.02=63.616\approx63.6$ amu

Answer:

63.6