Question

4​Fe+3O2→2Fe2O3
how does the equation show the law of conservation of mass

Answer 1

The Law of Conservation of Mass states that in a closed system, mass is conserved during a chemical reaction; that is, the mass of the reactants equals the mass of the products. To see how this is upheld in the chemical equation \(4Fe + 3O_2 \rightarrow 2Fe_2O_3\), we can look at the number of atoms of each element on both sides of the equation.

**Reactants:**
- Iron (Fe): There are 4 iron atoms.
- Oxygen (O): There are \(3 \times 2 = 6\) oxygen atoms (since \(O_2\) has 2 oxygen atoms and there are 3 molecules of \(O_2\)).

So, in total, the reactants contain:
- \(4\) Fe
- \(6\) O

**Products:**
In the product \(2Fe_2O_3\):
- Iron (Fe): There are \(2 \times 2 = 4\) iron atoms (since each \(Fe_2O_3\) molecule has 2 iron atoms and there are 2 molecules).
- Oxygen (O): There are \(2 \times 3 = 6\) oxygen atoms (since each \(Fe_2O_3\) has 3 oxygen atoms and there are 2 molecules).

So, in total, the products contain:
- \(4\) Fe
- \(6\) O

**Comparison:**
- Reactants: \(4\) Fe and \(6\) O
- Products: \(4\) Fe and \(6\) O

Since the number of each type of atom is the same on both sides of the equation, the total mass of the reactants equals the total mass of the products, thereby demonstrating the Law of Conservation of Mass.