Final answer:
The arrow in a chemical equation indicating the direction from reactants to products is known as the yield sign. It not only separates reactants from products but also indicates the direction of the chemical reaction. Special conditions such as heating or catalysis can be noted with symbols placed above or below this yield sign.
Step-by-step explanation:
The arrow in the middle of the equation separating the reactants and products is correctly referred to as the yield sign. In a chemical equation, the reactants which participate in the reaction are written on the left side, while the products formed are listed on the right side. The plus signs (+) are used to separate multiple reactants or products. Unlike a math equation, which uses an equal sign, a chemical reaction is represented by an arrow pointing towards the products. This arrow, or yield sign, explicitly denotes the direction of the reaction. Additionally, when a reaction is reversible and reaches equilibrium, a double-headed arrow replaces the yield sign. Symbols, such as a triangle indicating heating or a formula denoting a catalyst, can be written above or below the yield sign to specify particular conditions of the reaction.