Pls help for a and b and if possible pls give an explanation but you don’t have to!

What is the mass of 0.46 mol of mgcl2

How many moles of oxygen react with 12 moles of aluminum

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)