Question

based on the reaction and model below, what should be change about the model in order to balance the equation?
fe + o₂ ➔ __fe₂o₃
reactants
products
= fe atom
= o atom
one o2 molecule and one o atom should be added to the product
one fe atom and three o atoms should be removed from the reactant
one fe atom be added to the reactant and one fe2o3 molecule should be added to the product
one fe atom should be removed from the reactant and three o atoms added to the product

Explanation:

Step1: Count reactant atoms

Reactants: 3 Fe atoms, 6 O atoms (3 $\text{O}_2$ molecules)

Step2: Count product atoms

Products: 2 Fe atoms, 3 O atoms (1 $\text{Fe}_2\text{O}_3$ molecule)

Step3: Balance the chemical equation

Balance Fe first: Multiply $\text{Fe}_2\text{O}_3$ by 2, get 4 Fe atoms on product side. Multiply Fe reactant by 4. Now balance O: Product has 6 O atoms, so reactant $\text{O}_2$ is multiplied by 3. Balanced equation: $4\text{Fe} + 3\text{O}_2
ightarrow 2\text{Fe}_2\text{O}_3$

Step4: Compare to current model

Current reactants: 3 Fe, need 1 more Fe. Current products: 1 $\text{Fe}_2\text{O}_3$, need 1 more $\text{Fe}_2\text{O}_3$.

Answer:

One Fe atom be added to the reactant and one Fe2O3 molecule should be added to the product