How did you figure out the number of neutrons in each atom?

Given the following equation: 2a1 + 3mgcl2 --> 2alcl3 + 3mg how many moles of aluminum chloride are produced from 2.5 moles of magnesium chloride?

Which of the following reactions represents an exothermic reaction? nh3(g) + 12.0 kcal ½n2(g) + 3/2 h2(g) ch4 + 2o2 co2 + 2h2o + 212,800 cal c + 2s cs2, h = 27,550 cal c(graphite) c(diamond), h = 0.45 kcal 2h2o 2h2 + o2, h = +58 kcal

Sediment that settles on the bottom of the sea may form layers of rock which description tells how this sediment is deposited. a.)randomely b.)vertically c.)diagonally d.)horizontally