What does the triangle above the
arrow in a chemical equation mean? (A) Concentrated substances, (B)
diluted substances, (C) three substances present, (D) uniform crystals created, (E)
A chemical equation is a way to
represent a chemical reaction. A chemical equation is a set of
chemical formulas which represent the reactant and product substances in a chemical
reaction. The chemical equation for the
reaction between sodium and chlorine to produce sodium chloride is shown here. The arrow in a chemical equation
represents the chemical change occurring, with bonds breaking and forming. It separates the starting
substances from any new substances that are formed during the chemical reaction. We call the starting substances
reactants and the new substances products.
Sometimes, chemical reactions
require special conditions. For example, in order for magnesium
to react with oxygen, the magnesium must be heated. To indicate that a reaction
requires heat, we write a triangle above the arrow in the chemical equation. So, the triangle above the arrow in
a chemical equation means heat required, answer choice (E).