Question

how many grams of O2 is required for combustion 480 gram of MG find the mass of magnesium oxide formed in this reaction​

Answer 1

it is because they results in a negative charge in free energy ,Delta- G this may be as a result of the reaction being exothermic,so the product are more stable than the reactants or could be a result of an increase in entropy( product dissolves more than the reactants) , or both of these.

Another answer is because their activition is sufficient low so the successfull collision between the reactants particles can take place.