How is matter conserved in a chemical reaction

Matter is changed in a way that it can not be changed back to it's original form. The other answerer basically described a physical reaction.

"Both the initial and final substances are composed of atoms because all matter is composed of atoms. According to the law of conservation of matter, matter is neither created nor destroyed, so we must have the same number and type of atoms after the chemical change as were present before the chemical change." therefore, that is how matter is conserved