Conservation of Mass

Does expanding a material affect its mass? Why or why not?

Expansion can happen with or without a change in mass. For example, blowing more air into a balloon increases its mass. However, heating a piece of iron increases its volume without increasing its mass

Does burning a material affect its mass? Why or why not?

No, burning a material does not affect its mass. The law of conservation of mass states that matter cannot be created or destroyed. For example, when wood burns, the mass of the ashes, gases, and soot is equal to the original mass of the charcoal and oxygen. The mass of the product equals the mass of the reactant.

Recall that we saw the mass of the steel wool increase when we burned it in the lab. Why did this happen if we know the law of conservation of mass?

Steel wool increases in mass when burned because it reacts with oxygen from the air to form iron oxide, also known as rust. The iron oxide is heavier than the original iron, and the oxygen atoms add to the mass

Why could we expect to see the mass of a glass of water with an Alka Seltzer tablet decrease after the tablet dissolves?

The carbon dioxide dissolves in the water and then comes out of solution as a gas. This carbon dioxide gas has mass, but since it is a gas it escapes from the container and diffuses into the atmosphere. The loss of mass from the container is measured directly with the analytical balance.

What does the law of conservation of mass tell us?

The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. This means that the amount of matter cannot change.