How do you determine the difference between the

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?

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?