Which chemical equation best illustrates the law of conservation of mass? (my d)

2h2o yields h2 + o2

ch4 + 3o2 yields co2 + 2h2o

al4c3 + 3h2o yields ch4 + 4al(oh)3

zn + 2hcl yields zncl2 + h2

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.