Question

what is a chemical equation? it’s how we describe chemical reactions, using chemical symbols and formulas.
here’s an example (chemical equation for rust)
the arrow represents the “reaction taking place” or “yields”
reactant
product
4fe + 3o₂ → 2fe₂o₃
chemical symbol
coefficient – describes the quantity of the element or formula that follows it.
subscript – the number of atoms of the chemical symbol (element) to which the subscript is attached.
check for understanding

1. how many iron (fe) atoms are present within the reactant? ________
2. how many ‘o₂’ molecules are present within the reactant? ________
3. how many total atoms of oxygen are present within the reactant? ________
4. how many molecules of fe₂o₃ (rust) are present within the product? ________
5. how many iron (fe) atoms are present within the product? ________
6. how many oxygen (o) are present within the product? ________
7. does the number of atoms of each element on the reactant side match that of the product side? ________

Explanation:

Step1: Determine Fe atoms in reactant

The coefficient of Fe in the reactant is 4, so there are 4 Fe atoms.

Step2: Determine O₂ molecules in reactant

The coefficient of O₂ in the reactant is 3, so there are 3 O₂ molecules.

Step3: Determine total oxygen atoms in reactant

Each O₂ molecule has 2 oxygen atoms, and there are 3 O₂ molecules. So the total number of oxygen atoms is 3×2 = 6.

Step4: Determine Fe₂O₃ molecules in product

The coefficient of Fe₂O₃ in the product is 2, so there are 2 Fe₂O₃ molecules.

Step5: Determine Fe atoms in product

Each Fe₂O₃ molecule has 2 Fe atoms, and there are 2 Fe₂O₃ molecules. So the number of Fe atoms is 2×2=4.

Step6: Determine oxygen atoms in product

Each Fe₂O₃ molecule has 3 oxygen atoms, and there are 2 Fe₂O₃ molecules. So the number of oxygen atoms is 2×3 = 6.

Step7: Check atom - balance

On the reactant side: 4 Fe atoms and 6 O atoms. On the product side: 4 Fe atoms and 6 O atoms. The number of atoms of each element on the reactant side matches that of the product side.

Answer:

1. 4
2. 3
3. 6
4. 2
5. 4
6. 6
7. Yes