Which represents an endothermic reaction? wood burning in a fire splitting a gas molecule changing frost to water vapor TNT exploding

How is the composition of a meteorite relevant to finding out the composition of earth's core?

What is the formula for the compound dinitrogen pentoxide? a. n4o5 b. n5o4 c. n4o6 d. n5o2 e. n2o5

From the options provided for each element below, choose the properties that it may have based on its location in the periodic table fluorine (f): highly reactive nonmetal shiny a conductor