The difference in mass between two substances can arise due to various factors, including the number of constituent particles and the mass of individual atoms.
The mass of a substance is primarily determined by the total number and type of particles it contains. These particles can include atoms, molecules, ions, or other subatomic particles. The mass of a substance depends on the combined mass of all these constituent particles.
In terms of atoms, different elements have different masses. Atoms are composed of protons, neutrons, and electrons. The mass of an atom is primarily determined by the combined mass of its protons and neutrons, located in the nucleus. Electrons, which orbit the nucleus, contribute very little to the overall mass of an atom.
The number of atoms in a substance can also contribute to its overall mass. For example, if two substances are composed of the same type of atom but have different amounts, the substance with a greater number of atoms will have a greater mass.
It's important to note that not all atoms have the same mass. Each element on the periodic table has a unique atomic mass, which is a weighted average of the masses of its isotopes. Isotopes are variants of an element that have the same number of protons but differ in the number of neutrons. Since the number of neutrons can vary, different isotopes of an element will have slightly different atomic masses.
In summary, the mass of a substance can differ due to factors such as the number of constituent particles (atoms, molecules, ions, etc.) and the mass of individual atoms. Different elements have different atomic masses, and the total mass of a substance is determined by the combined mass of its constituent particles.