In a chemical equation, what does a coefficient show?
A. the number of atoms of an element present in a molecule in the chemical reaction
B. the number of reactants present in the chemical reaction
C. the number of molecules needed to balance a chemical equation
D. the number of molecules of a substance present in the chemical reaction
C. the number of molecules needed to balance a chemical equation
C. the number of molecules needed to balance a chemical equation
In a chemical equation, a coefficient represents the number of molecules or formula units of a substance involved in the chemical reaction. It shows the relative amounts of the substances reacting or being produced.
To determine the significance of a coefficient in a chemical equation, you can follow these steps:
1. Write the balanced chemical equation, which shows the reactants and products involved in the reaction.
2. Identify the coefficients in the equation, which are the whole numbers written in front of each reactant or product.
3. For option (A), consider the coefficients as the number of atoms of an element present in a molecule in the chemical reaction. This is not the correct interpretation because coefficients actually represent the number of molecules or formula units, not individual atoms.
4. For option (B), consider the coefficients as the number of reactants present in the chemical reaction. While there may be multiple reactants, the coefficients represent the number of molecules or formula units of each reactant, not the total number of reactants.
5. For option (C), consider the coefficients as the number of molecules needed to balance a chemical equation. This is the correct interpretation. Coefficients are adjusted during the process of balancing equations to ensure that the number of atoms of each element is the same on both sides of the equation. The coefficients indicate the ratio of the number of molecules involved in the reaction.
6. For option (D), consider the coefficients as the number of molecules of a substance present in the chemical reaction. This is also a correct interpretation. The coefficients provide the molar ratios between different substances in the reaction, allowing us to determine the stoichiometry of the reaction.
Therefore, the correct answer is C. The coefficient in a chemical equation represents the number of molecules needed to balance a chemical equation.