How many moles of nitrogen are contained in 1.61 x 10^24

How many moles of al3+ ions are in 1.25 moles of al2o3

The identities of substances are the same before and after which type of change

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.