<u>Answer:</u> In a chemical reaction, the total mass of the particles in the system stays the same
<u>Explanation:</u>
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side in a chemical reaction.
Every balanced chemical reaction follows law of conservation of mass.
<u>For Example:</u> Formation of water molecule

Total mass on reactant side = ![[2(2\times 1)+(2\times 16)]=36g/mol](https://tex.z-dn.net/?f=%5B2%282%5Ctimes%201%29%2B%282%5Ctimes%2016%29%5D%3D36g%2Fmol)
Total mass on product side = ![[2((2\times 1)+16)]=36g/mol](https://tex.z-dn.net/?f=%5B2%28%282%5Ctimes%201%29%2B16%29%5D%3D36g%2Fmol)
Hence, in a chemical reaction, the total mass of the particles in the system stays the same
I would say chemical but I’m not 100% sure might wanna get a second opinion