What is the primary purpose of adding a coefficient to a chemical equation?

• A. To specify the temperature at which the reaction occurs
• B. To indicate the physical state of a substance
• C. To show the charge of an ion in the reaction
• D. To ensure the number of atoms of each element is the same on both sides of the equation

Answer: (D)

Verified step by step guidance

1. Understand that a chemical equation represents a chemical reaction, showing reactants on the left and products on the right.
2. Recognize that atoms are neither created nor destroyed in a chemical reaction, so the number of atoms of each element must be the same on both sides of the equation.
3. Learn that coefficients are numbers placed before chemical formulas in an equation to balance the number of atoms for each element.
4. Know that coefficients adjust the quantity of molecules or moles of substances involved, ensuring the law of conservation of mass is obeyed.
5. Distinguish that coefficients do not indicate temperature, physical state, or ionic charge; those are shown by other notations such as state symbols (s, l, g, aq) or charges on ions.