# How can the law of conservation of mass apply to a burning log?

##### 1 Answer
Apr 8, 2018

The law of conservation of mass states that, for any closed system, the mass of the system must remain constant.
So, in other words, mass cannot be created nor destroyed.

In a burning log, the initial mass of the wood and the ashes that are left behind after it burns are different, which would seem to violate the law of conservation of mass.

However, the rest of the mass is actually in the form of $C {O}_{2}$ and ${H}_{2} O$ that were also produced as the log burned.