National League for Nursing (NLN PAX) Practice Exam

In the reaction of iron with water, what coefficient balances the reaction: Fe + 4H2O ° Fe3O4 + 4H2?

1. 2

2. 3

3. 4

4. 6

The correct answer is: 3

In the given reaction of iron with water, we need to ensure that both the number of atoms of each element and the overall charge are balanced on both sides of the equation. We start with the unbalanced equation: Fe + 4H2O → Fe3O4 + 4H2 To balance the reaction, let’s analyze the components: On the left side, we have: - 1 atom of Fe - 4 molecules of H2O, giving us 4 O atoms and 8 H atoms in total. On the right side, we can break down the products: - Fe3O4 contains 3 Fe atoms and 4 O atoms. - 4H2 produces 8 H atoms. In order to balance the reactions, we can see that we need 3 iron atoms on the left to correspond with the 3 iron atoms in Fe3O4 on the right. Therefore, the coefficient for Fe should be 3. The balancing leads to: 3Fe + 4H2O → Fe3O4 + 4H2 This properly accounts for the mass on both sides: 3 Fe, 4 O, and 8 H atoms balance out. Thus,