What can be used in the absence of enthalpies of formation to calculate approximate enthalpy changes?

Two atoms interact with each other as shown by the equation. complete the equation by filling in the missing parts. 1 2 3 4 5 h he li

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium.b)heavier than helium.c)the same weight as helium.d)dependent on the element that reacted with carbon.