Here's why:

* Atomic Mass: Carbon has an atomic mass of approximately 12 atomic mass units (amu), while hydrogen has an atomic mass of approximately 1 amu.

* Protons and Neutrons: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Carbon has 6 protons and 6 neutrons, while hydrogen has 1 proton and no neutrons. This difference in nuclear composition makes carbon significantly heavier.