Is a tree burning a chemical or physical change

Calculate the molarity of 48.0 ml of 6.00 m h2so4 diluted to 0.250 l .

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?

How hot is the suns corona? (integrated science)