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Question Video: Recognizing What a Triangle Written above the Arrow in a Chemical Equation Means Science

What does the triangle above the arrow in a chemical equation mean?

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Video Transcript

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) heat required.

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).

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