# Does burning reduce mass?

## Does burning reduce mass?

Burning and other changes in matter do not destroy matter. The mass of matter is always the same before and after the changes occur. The law of conservation of mass states that matter cannot be created or destroyed.

## Why does burning steel wool increase the mass?

The heat and large amount of surface area allows the iron in the steel wool to burn or combine with the oxygen in the air. This accelerated oxidation is rusting. The steel wool weighs more after it is burned. Since oxygen atoms have mass and are joined to the iron atoms, the resultant compound weighs more.

Does mass increase when heated?

All internal energy such as thermal, rotational, and internal potential energy contributes to the rest mass of an object. So, yes, a hot object has greater rest mass and would weigh more when measured, if a scale were sensitive enough.

Why are hot objects heavier?

The reason why hot objects are heavier is because E=mc^2. If you have absolutely identical objects that have the same weight exactly when they are at same temperature, then when one object is heated, it will weigh more. This is because the gravitational force depends on the stress energy tensor in general relativity.

### Does water lose mass when heated?

When water is heated, it expands, or increases in volume. When water increases in volume, it becomes less dense. As water cools, it contracts and decreases in volume. When water decreases in volume, it becomes more dense.

### Does density change when heated?

Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.

What happens to mass if the volume increases?

The amount of material an object contains. If the volume of the object stays the same but the mass of the object increases then its density becomes greater.