The average atomic mass of nitrogen is 14.01 u.
Nitrogen exists naturally as nitrogen-14 (mass =
14.00 u) and nitrogen-15 (mass = 15.00 u). What can
you infer about the isotopic abundances for nitrogen?
PLEASE EXPLAIN THE ANSWER
i have the same question the teacher said she will put it on the teset but diffrent element can some expalin more
Well, when it comes to nitrogen, it seems like nature can't make up its mind! The atomic mass of nitrogen is 14.01 u, but we know that it exists in two different isotopes - nitrogen-14 and nitrogen-15. The isotope nitrogen-14 has a mass of 14.00 u, while nitrogen-15 has a mass of 15.00 u.
So, based on the average atomic mass and the existence of these isotopes, we can infer that the isotopic abundances for nitrogen are not equal. Since the average atomic mass is slightly greater than the mass of nitrogen-14, it suggests that there must be a higher abundance of nitrogen-15.
It's like having a pizza with two different toppings, but one of them is a bit more plentiful. In this case, nitrogen-15 is the extra pepperoni on our atomic pizza!
To infer the isotopic abundances for nitrogen, we can make use of the concept of weighted average atomic mass.
The average atomic mass of nitrogen given is 14.01 u. This means that, on average, nitrogen atoms have a mass of 14.01 atomic mass units (u).
Nitrogen has two naturally occurring isotopes: nitrogen-14 (mass = 14.00 u) and nitrogen-15 (mass = 15.00 u). Isotopes are variants of an element that have the same atomic number but differ in the number of neutrons.
To calculate the isotopic abundances of nitrogen, we need to consider that the average atomic mass is a weighted average of the isotopes' masses, where the weights are the relative abundances of each isotope.
Let's represent the isotopic abundance of nitrogen-14 as x (expressed as a decimal) and the isotopic abundance of nitrogen-15 as (1-x). Since the sum of the abundances is equal to 1, the abundance of nitrogen-15 can be represented as (1 - x).
The average atomic mass can be calculated as the sum of the products of each isotope's abundance and mass:
14.01 u = x * 14.00 u + (1 - x) * 15.00 u
Now, we can solve this equation to find the value of x, which represents the isotopic abundance of nitrogen-14:
14.01 u = 14.00 u * x + (15.00 u - 15.00 u * x)
14.01 u = 14.00 u * x + 15.00 u - 15.00 u * x
14.01 u - 15.00 u = - 1.00 u * x
-0.99 u = -1.00 u * x
x = -0.99 u / -1.00 u
x = 0.99
Therefore, we can infer that the isotopic abundance of nitrogen-14 is approximately 0.99 (or 99%) and the isotopic abundance of nitrogen-15 is approximately (1 - 0.99) = 0.01 (or 1%).
would be 14.50 so it's much much less than 50%.
Meaning that it is about 99% of the 14.00 and about 1% of the 15.00. On the web I found these numbers. 99.636% for the 14.00 and 0.00364% for the 15.00.
This is really a math question. Remember that the atomic masses of elements is a weighted average of each of the isotopes.
So you have one isotope with a mass of 14.00 and another with a mass of 15.00. If the average of the two is 14.01 it should be logical that there is much more of the 14.00 than the 15.00. Think about it. If they were 50% each then the mass of the element would be 14.50 so it's much much less than 50%.