What is the approximate mass of a hydrogen atom in kilograms?

The mass of a hydrogen atom is indeed very close to 1.67492728 x 10^(-27) kg, which is the standard value typically referenced in scientific literature. This mass reflects the mass of a single hydrogen atom, which is essential for understanding atomic structure and processes in chemistry and physics.

Hydrogen, being the simplest and lightest element, has a nucleus consisting of a single proton. When considering the mass of an atom, we use the weighted average that includes not only the mass of the protons but also the electrons, though their contribution is negligible compared to that of the protons and neutrons. The value cited in the correct answer is an approximation based on the fundamental constants that define atomic masses.

The other choices provided do not correspond to the mass of a hydrogen atom. The value given as approximately 9.1093826 x 10^(-31) kg corresponds to the mass of an electron, while the other choice refers to a constant related to quantum mechanics (Planck's constant) and does not pertain to atomic mass at all.