"Chemicals Compose Ordinary Things"

Chemical Composition of Ordinary Things (https://chem.libretexts.org/Courses/Palomar_College/PC%3A_CH....):

•  Chemistry is the branch of science dealing with the structure, composition, properties, and reactive characteristics of matter. Matter is anything that has mass and occupies space. 

• Matter is defined as any substance that has mass. It’s important to distinguish here between weight and mass. Weight is the result of the pull of gravity on an object. On the Moon, an object will weigh less than the same object on Earth because the pull of gravity is less on the Moon. 

• The mass of an object, however, is an inherent property of that object and does not change, regardless of location, or gravitational pull. It is a property that is solely dependent on the quantity of matter within the object. Contemporary theories suggest that matter is composed of atoms. 

• Atoms themselves are constructed from neutrons, protons, and electrons, along with an ever-increasing array of other subatomic particles. We will focus on the neutron, a particle having no charge, the proton, which carries a positive charge, and the electron, which has a negative charge. Atoms are incredibly small. To give you an idea of the size of an atom, a single copper penny contains approximately 28,000,000,000,000,000,000,000 atoms (that’s 28 sextillions). Because atoms and subatomic particles are so small, their mass is not readily measured using pounds, ounces, grams, or any other scale that we would use on larger objects. Instead, the mass of atoms and subatomic particles is measured using atomic mass units (abbreviated amu).

•  The atomic mass unit is based on a scale that relates the mass of different types of atoms to each other (using the most common form of the element carbon atom as a standard). The AMU scale gives us a convenient means to describe the masses of individual atoms and to do quantitative measurements.