The Conservation of Mass: Understanding Reactions

The Conservation of Mass is an important rule in science. It says that in a chemical reaction, mass cannot be created or destroyed. This idea is key when we look at two types of reactions: exothermic and endothermic.

1. Exothermic Reactions:

• Exothermic reactions give off energy, usually as heat.
• For example, when methane (a type of gas) burns with oxygen, it creates carbon dioxide and water while letting out energy.

Here’s a simple breakdown:

• If we have 16 grams of methane and 64 grams of oxygen, the total mass before the reaction is 80 grams.
• After the reaction, we get 44 grams of carbon dioxide and 36 grams of water, which also equals 80 grams.

So, the total mass stays the same!

2. Endothermic Reactions:

• Endothermic reactions absorb energy from their surroundings.
• A good example is when calcium carbonate is heated. It breaks down into calcium oxide and carbon dioxide.

Again, the mass before and after the reaction remains unchanged.

In both types of reactions, the mass of what you start with (the reactants) is equal to the mass of what you end up with (the products).

This shows us the Conservation of Mass in action!

Knowing this principle helps scientists make smart guesses and calculations about how reactions happen.