‘Chemical equations must be balanced to satisfy the
A) law of definite proportions B) law of multiple proportions C) law of conservation of mass D) principle of Avogadro
The correct answer and explanation is:
The correct answer is C) law of conservation of mass.
Chemical equations must be balanced to adhere to the law of conservation of mass, which states that mass cannot be created or destroyed in a chemical reaction. This principle was established by Antoine Lavoisier in the late 18th century and forms the foundation for all modern chemistry. In a chemical reaction, the total mass of the reactants must be equal to the total mass of the products. To ensure this, the number of atoms of each element on the left side of the equation (reactants) must be the same as on the right side (products).
When a chemical equation is balanced, it reflects the exact quantities of reactants and products involved in the reaction. This ensures that no atoms are lost or gained during the process, aligning with the law of conservation of mass. For example, in the combustion of methane:
CH4+2O2→CO2+2H2OCH_4 + 2 O_2 \rightarrow CO_2 + 2 H_2O
Each element (carbon, hydrogen, oxygen) is accounted for in equal numbers on both sides of the equation. The balancing process typically involves adjusting coefficients in front of molecules, rather than altering the chemical formulas of the substances themselves.
Balancing chemical equations is essential for accurate stoichiometric calculations, as it allows chemists to determine the amounts of reactants needed and products produced. This principle is crucial in laboratory work, industrial processes, and even environmental science, where mass balance calculations are needed to understand reactions such as those in the atmosphere or ecosystems. Thus, the law of conservation of mass is fundamental to the process of balancing chemical equations.