The "Dawn horses" were actually not related to horses! Recent studies of fossils found that "Dawn Horses" were buried in the same rock layers as modern horses! evolutionists were shocked at first but then decided that the "Dawn horse" was related to rabbits! Now to answer your question no one really knows why they went extinct. Evolutionist believe they changed into rabbits and Creationists (people who believe God created the universe and that evolution is incorrect) believe they died out due to climate changes after the global flood of Noah.
Answer:
Atom is a the smallest particle of a chemical element that can exist.
Molecules is a a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
Particles is a minute portion of matter.
A particle can be a single atom or a molecule ( a group of atoms held together by chemical bonds).
An acid is a proton donor
8.5L H2O (1 mol H2O/22.4L)=.37946 mol H2O
.3796 mol H2O(1 mol CH4/2 mol H2O)=.18973 mol CH4
.18973 mol CH4(22.4L/1mol CH4)=4.25L CH4 gas