Question

1. calculate the average atomic mass of the following: show all work!!!

isotope\tmass (amu)\tpercent abundance
boron - 10\t10.013\t7.50%
boron - 11\t11.009\t92.50%

1. calculate the average atomic mass of the following: show all work!!!

isotope\tmass (amu)\tpercent abundance
sulfur - 32\t31.972\t95.00%
sulfur - 33\t32.971\t0.760%
sulfur - 34\t33.967\t4.220%

1. calculate the average atomic mass of the following: show all work!!!

isotope\tmass (amu)\tpercent abundance
chlorine - 35\t34.969\t75.78%
chlorine - 37\t36.966\t24.22%

Explanation:

Step1: Recall the formula for average atomic mass

The formula for average atomic mass ($A_{avg}$) is $A_{avg}=\sum_{i} (m_i\times p_i)$, where $m_i$ is the mass of the isotope and $p_i$ is the percent - abundance (expressed as a decimal) of the isotope.

Step2: Calculate the average atomic mass for boron

For boron:
The percent - abundance of Boron - 10, $p_1 = 7.50\%=0.0750$, and its mass $m_1 = 10.013$ amu.
The percent - abundance of Boron - 11, $p_2=92.50\% = 0.9250$, and its mass $m_2 = 11.009$ amu.
$A_{avg}=(10.013\times0.0750)+(11.009\times0.9250)$
$=0.750975 + 10.183325$
$=10.9343$ amu

Step3: Calculate the average atomic mass for sulfur

For sulfur:
The percent - abundance of Sulfur - 32, $p_1 = 95.00\%=0.9500$, and its mass $m_1 = 31.972$ amu.
The percent - abundance of Sulfur - 33, $p_2 = 0.760\%=0.00760$, and its mass $m_2 = 32.971$ amu.
The percent - abundance of Sulfur - 34, $p_3 = 4.220\%=0.04220$, and its mass $m_3 = 33.967$ amu.
$A_{avg}=(31.972\times0.9500)+(32.971\times0.00760)+(33.967\times0.04220)$
$=30.3734+0.2405796 + 1.4334074$
$=32.047387$ amu $\approx32.047$ amu

Step4: Calculate the average atomic mass for chlorine

For chlorine:
The percent - abundance of Chlorine - 35, $p_1 = 75.78\%=0.7578$, and its mass $m_1 = 34.969$ amu.
The percent - abundance of Chlorine - 37, $p_2 = 24.22\%=0.2422$, and its mass $m_2 = 36.966$ amu.
$A_{avg}=(34.969\times0.7578)+(36.966\times0.2422)$
$=26.4096082+8.9531652$
$=35.3627734$ amu $\approx35.363$ amu

Answer:

Boron average atomic mass: 10.9343 amu
Sulfur average atomic mass: 32.047 amu
Chlorine average atomic mass: 35.363 amu