5. Pure water can be described as. (Check all that apply) Mixture
Pure substance
Element
Compound
Heterogeneous mixture
Homogeneous mixture

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

the correct answer would be b) volume versus temperature, because they are also directly proportional.