Final answer:
The law of conservation of mass ensures that the mass of reactants and products in a chemical reaction remain equal. By correctly balancing the chemical equation 3Ca + 2FeCl3 -> 3CaCl2 + 2Fe with appropriate coefficients and without altering its subscripts, we illustrate this law. Mass is conserved because the total number of atoms for each element is the same on both sides of the equation.
Step-by-step explanation:
The law of conservation of mass states that in any chemical reaction, the total mass of the reactants must equal the total mass of the products. This principle is crucial when understanding how chemical equations are balanced. For the equation 3Ca + 2FeCl3 -> 3CaCl2 + 2Fe, the reactants are calcium (Ca) and iron(III) chloride (FeCl3), while the products are calcium chloride (CaCl2) and iron (Fe).
Let's breakdown the elements involved in terms of subscripts and coefficients:
- Subscripts indicate the number of atoms of an element in a molecule. For example, in FeCl3, the subscript '3' indicates there are three atoms of chlorine for every atom of iron.
- Coefficients are numbers placed before the formulas of reactants or products to indicate how many molecules or moles are involved. In this equation, '3' before Ca means there are three atoms of calcium as reactants.
To demonstrate that this equation obeys the law of conservation of mass, we must ensure the number of atoms of each element is the same on both sides of the equation. The coefficients help us balance the reaction, thus maintaining the total mass. We do not change the subscripts because they are fundamental to the identity of the compounds, and altering them would change the actual substance rather than the quantity involved in the reaction. By correctly balancing the equation with appropriate coefficients, we show that mass is conserved without changing the identities of the substances involved.