Help me pass this test my last day of school is may 26 if you don’t mind I have more questions :)

What is the number of moles in 15.0 g ash3?

Which statement best describes the oxidation numbers of the atoms found in magnesium chloride? a. magnesium has a 2- oxidation number and chlorine has a 1+ oxidation number. b. magnesium has a 2- oxidation number and chlorine has a 2+ oxidation number. c. magnesium has a 2+ oxidation number and chlorine has a 1- oxidation number. d. magnesium has a 1+ oxidation number and chlorine has a 1- oxidation number.

How many moles of gas are present if p=11 atm, v=12l, t=185k?