1) What is the definition of stoichiometry? 2) What are isotopes? 3) What is a mole? 4) What is Avogadro's number? 5) What is the molar mass?

1. Stoichiometry is the calculation of reactants and products in chemical reactions in terms of the amount of substance (usually in moles) using balanced chemical equations.<br />2. Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses.<br />3. A mole is a unit of measurement in chemistry that represents Avogadro's number (6.022 x 10^23) of entities (atoms, molecules, ions, etc.).<br />4. Avogadro's number, also known as Avogadro's constant, is the number of entities (atoms, molecules, ions, etc.) in one mole of a substance, which is approximately 6.022 x 10^23.<br />5. Molar mass is the mass of one mole of a substance, usually expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a molecule or compound.