Average Atomic Mass

Atoms — and the protons, neutrons, and electrons that compose them — are extremely small. For example, a carbon atom weighs less than 2 × 10−23 g. When describing the properties of tiny objects such as atoms, we use appropriately small units of measure, such as the atomic mass unit (amu). The amu was originally defined based on hydrogen, the lightest element, then later in terms of oxygen. Since 1961, it has been defined with regard to the most abundant isotope of carbon, atoms of which are...

The number of protons in the nucleus of an atom is its atomic number (Z). This is the defining trait of an element. Its value determines the identity of the atom. For example, any atom that contains six protons is the element carbon and has the atomic number 6, regardless of how many neutrons or electrons it may have. A neutral atom must contain the same number of positive and negative charges, so the number of protons equals the number of electrons. This means that the atomic number also...

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, water, H2O, and hydrogen peroxide, H2O2, are alike in that their respective molecules are composed of hydrogen and oxygen atoms. However, because a hydrogen peroxide molecule contains two oxygen atoms, as opposed to the water molecule, which has only one, the two substances exhibit very different properties. Atoms and molecules are extremely...

The Average Fixed Cost, or AFC curve, is the graphical representation of the average fixed cost. It starts at the first unit of output. As the level of output increases, the same fixed cost is allocated across more units, leading to a decrease in the AFC. This relationship results in a downward-sloping AFC curve across all potential levels of output. The curve approaches zero but never actually reaches it. The Average Variable Cost (AVC) curve begins when the output is one unit. At low levels...

Average Fixed Cost (AFC) is the total fixed cost per unit of output. It's calculated by dividing the total fixed costs (TFC) by the quantity of output produced. Since TFC does not change with the level of output, the AFC continuously decreases as output increases. This is because the same amount of TFC is spread over an ever larger number of units. For example, if the total fixed costs for a business are $1,000 and it produces 100 units, the AFC would be $10 per unit. If production increases to...