Answer:
The answer to your question is: 12.011 amu
Explanation:
Carbon -12 mass = 12.00 amu abundance = 98.9 %
Carbon-13 mass = 13 amu abundance = 1.10 %
atomic mass of carbon = (mass number isotope 1)(abundance) / 100+
(mass number isotope 2)(abundance) / 100
atomic mass of carbon = (12)(0.989) + (13)(0.011) = 11.868 + 0.143
= 12.011 amu
Considering the definition of atomic mass, isotopes and atomic mass of an element, the average mass of carbon is 12.011 amu.
An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.
Every atom consists of:
In other words, the atomic nucleus is the central part of the atom that is made up of protons and neutrons, while the orbitals or peripheral region is an area where electrons are found.
On the other hand, the mass number tells us the total number of particles in the nucleus. That is, the mass number is the sum of the number of protons and the number of neutrons in the atomic nucleus.
The same chemical element can be made up of different atoms, that is, their atomic numbers are the same, but the number of neutrons is different. These atoms are called isotopes of the element.
On the other hand, the atomic mass of an element is the weighted average mass of its natural isotopes. In other words, the atomic masses of chemical elements are usually calculated as the weighted average of the masses of the different isotopes of each element, taking into account the relative abundance of each of them.
In this case, Carbon-12 is 98.9% abundant (the atomic mass is 12 amu) and Carbon-13 (the atomic mass is 13 amu) is 1.10% abundant. Then, the average mass of lithium can be calculated as:
12 amu×0.989 + 13 amu×0.011= 12.011 amu
Finally, the average mass of carbon is 12.011 amu.
Learn more:
