QQuestionChemistry
QuestionChemistry
Bromine has two isotopes, with mass numbers 79 and 81. Its relative atomic mass is often given as 80. What does that tell you about the relative abundance of the two isotopes?
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Answer
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Step 1:Let's solve this step by step:
Step 2:: Understand the Given Information
- Bromine has two isotopes with mass numbers 79 and 81 - The relative atomic mass is 80 - We need to determine the relative abundance of these isotopes
Step 3:: Set Up the Weighted Average Calculation
80 = 79x + 81(1-x)
The relative atomic mass is the weighted average of the isotope masses, where the weights are their natural abundances. The weighted average calculation can be expressed as:
Step 4:: Algebraic Manipulation
80 = 79x + 81 - 81x
80 = 81 - 2x
Step 5:: Solve for x
2x = 1
x = \frac{1}{2}
Step 6:: Interpret the Result
- Fraction of $$^{79}Br$$ is $$\frac{1}{2}$$ or 50%
- Fraction of ^{81}Br is also \frac{1}{2} or 50%
Final Answer
The two isotopes of bromine (^{79}Br and ^{81}Br) are present in equal proportions, each making up 50% of naturally occurring bromine.
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