The total mass number of the reactants equals the total mass number of the products.
Here's how it works:
* Mass Number: The mass number of an atom is the sum of its protons and neutrons.
* Chemical Reactions: In chemical reactions, atoms are rearranged, not created or destroyed. The number of protons and neutrons in each atom remains the same.
* Conservation: This means that the total number of protons and neutrons on the reactant side of the equation must be equal to the total number on the product side.
Example:
Consider the combustion of methane (CH₄):
CH₄ + 2O₂ → CO₂ + 2H₂O
* Reactants:
* CH₄: Mass number = 12 (C) + 4 (H) = 16
* 2O₂: Mass number = 2 * 32 (O) = 64
* Total reactant mass number = 16 + 64 = 80
* Products:
* CO₂: Mass number = 12 (C) + 2 * 16 (O) = 44
* 2H₂O: Mass number = 2 * (2 (H) + 16 (O)) = 36
* Total product mass number = 44 + 36 = 80
The total mass number on the reactant side (80) equals the total mass number on the product side (80). Therefore, the principle of conservation of mass number is satisfied in this chemical equation.
Key Points:
* The principle of conservation of mass number is also known as conservation of nucleons.
* It's important to remember that this principle applies to nuclear reactions as well, where the number of protons and neutrons can change.
* Balancing chemical equations ensures the conservation of mass number.
Let me know if you have any further questions!
