Why do some objects float, while others sink?

When determining the shape of a molecule, it is important to draw a lewis dot structure first in order to see the total number a. electrons within the moleculeb. bonding and unshared pairs around central atomc. unshared pair within the molecule( i really need it )

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Hey guys so i need to know what is _nh3+> nh4oh ~chemistry~