No, carbon-12 (C-12) and carbon-14 (C-14) do not have the same atomic mass. The atomic mass of an isotope is determined by the number of protons and neutrons in its nucleus.
Carbon-12 has 6 protons and 6 neutrons, giving it an atomic mass of approximately 12 atomic mass units (amu). It is the most common and stable isotope of carbon, accounting for about 98.9% of natural carbon.
On the other hand, carbon-14 has 6 protons and 8 neutrons, resulting in an atomic mass of around 14 amu. Carbon-14 is a radioactive isotope of carbon and is used in carbon dating to determine the age of organic materials.
So, while both isotopes belong to the element carbon, they have different atomic masses due to the varying number of neutrons in their nuclei.