The measure of central angle ABC is n/2 radian. What is the area of the shaded sector? 6n units2, 9n units2, 18n units2, 36n units2

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?