wilson, makyla dtal - ch - term 1 - unit 2 assessment 25 - 26 what is the atomic mass of silicon if 92.21%…

wilson, makyla dtal - ch - term 1 - unit 2 assessment 25 - 26 what is the atomic mass of silicon if 92.21% of its atoms have a mass of 27.977 amu, 4.70% have a mass of 28.976 amu, and 3.09% have a mass of 29.974 amu? round your answer to four significant digits and only include the number without the units for the answer. assume the units to be in amu.

wilson, makyla dtal - ch - term 1 - unit 2 assessment 25 - 26 what is the atomic mass of silicon if 92.21% of its atoms have a mass of 27.977 amu, 4.70% have a mass of 28.976 amu, and 3.09% have a mass of 29.974 amu? round your answer to four significant digits and only include the number without the units for the answer. assume the units to be in amu.

Answer

Answer:

27.98

Explanation:

Step1: Recall atomic - mass formula

The atomic mass ($A$) is calculated using the formula $A=\sum_{i}x_im_i$, where $x_i$ is the fractional abundance and $m_i$ is the mass of the isotope.

Step2: Convert percentages to fractions

$92.21% = 0.9221$, $4.70%=0.0470$, $3.09% = 0.0309$.

Step3: Calculate atomic mass

$A=(0.9221\times27.977)+(0.0470\times28.976)+(0.0309\times29.974)$ $A = 0.9221\times27.977=25.692$ (first - term calculation) $A = 0.0470\times28.976 = 1.362$ (second - term calculation) $A = 0.0309\times29.974=0.926$ (third - term calculation) $A=25.692 + 1.362+0.926$ $A = 27.98$.