Complex sentence: Dalton hypothesized this was due to the differences between the masses and configurations of the gases' respective particles, and carbon dioxide molecules (CO 2) are heavier and larger than nitrogen molecules (N 2).
Split into simpler sentences: Dalton hypothesized this was due to the differences in mass and complexity of the gases' respective particles. Indeed, carbon dioxide molecules (CO 2) are heavier and larger than nitrogen molecules (N 2).