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Given the average atomic mass of an element, find the % abundance of its isotopes

Grade 10 SABIS


Given the average atomic mass of an element: It's like having the average weight of a group of people.


Isotopes: Think of them as different "versions" of the same element, like having people with varying heights within the group.


Each isotope of an element has a specific mass, just like each person in the group has a unique weight.


The average atomic mass takes into account the mass of each isotope and their respective abundance in nature, similar to calculating the average weight of a group considering each person's weight and how many people there are of each height.


To find the percentage abundance of isotopes, we'll use a formula that involves the average atomic mass and the masses of the isotopes.


For example, let's say we have an element with two isotopes: Isotope A with a mass of 10 and Isotope B with a mass of 12.


The average atomic mass of the element is given as 11.2.


We'll assign variables to the abundance of each isotope, such as x for the abundance of Isotope A and y for the abundance of Isotope B.


The average atomic mass is the weighted average of the masses of the isotopes, so we'll set up an equation: (x * 10) + (y * 12) = 11.2.


Since the percentages must add up to 100%, we know that x + y = 100.


Now, we have a system of two equations: (x * 10) + (y * 12) = 11.2 and x + y = 100.


Solving these equations simultaneously, we can find the values of x and y, which represent the percentage abundances of the isotopes.


Let's say we find that x = 60 and y = 40.


This means that Isotope A makes up 60% of the element's total abundance, while Isotope B contributes 40%.


In our everyday lives, we encounter similar situations when analyzing data or determining proportions in various scenarios.


For instance, in a bag of assorted candies, finding the percentage of each type is like finding the abundance of isotopes.


The average atomic mass provides us with a useful reference point, just as the average weight of a group helps us understand its overall characteristics.


By understanding the percentage abundances of isotopes, scientists can gain insights into the natural distribution of elements and how they behave in different contexts.


Analyzing the percentage abundances of isotopes is crucial in fields such as geology, chemistry, and forensic science, where precise knowledge of element compositions is essential.


In summary, by considering the average atomic mass and the masses of individual isotopes, we can determine the percentage abundances of isotopes, offering a deeper understanding of the element's composition and its significance in various scientific disciplines.

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