Answer:
1) Big Bang Theory
2) we are in a phase of the big bang theory
Explanation:
So for number 1 the answer is the -big bang theory- and number 2 there is a theory that pretty much says that were in a constant cycle. what I mean is theoretically in a couple million years the entire universe will form together again into another dense ball and repeat the process. So basically the universe is still in the "expanding phase" and that's what backs up the theory of the big bang (the fact that were in one of the big bang theory's "phases")
The mass of oxygen and hydrogen must be equal to the mass of the substance they create the water. So if the hydrogen is 2.8 g the oxygen must account for the rest of the mass. Basically just subtract 25.4-2.8=mass of oxygen
Molar mass of empirical formula = 172.8 g/mole
346.6g/172.8 g/mole = 2.00 moles
Molecular formula = C2H2Br4
One of the major events is Volcanos etc...