[xzins]

Do you lose mass of water over time? For example, if a liter is converted into H’s and O’s, and then you burn it, and it reforms back into 2 molecules of water, will you end up with a liter of water or will you have less?

[neverdem]

Do you lose mass of water over time? For example, if a liter is converted into H’s and O’s, and then you burn it, and it reforms back into 2 molecules of water, will you end up with a liter of water or will you have less?

In chemical reactions, you always have conservation of mass. Nuclear reactions are different, but you still have to have a total conservation of mass and energy even if the energy is lost as heat, etc. The loss of mass is converted to energy.