4. A piece of steel wool heated in air (20% oxygen) burns slowly, but when heated in pure oxygen, undergoes rapid combustion, as evidenced by a dazzling shower of sparks

An observation that requires measurement is called quantitative observable or qualitative

Which is true of a liquid? it has a definite volume but not a definite mass.it has a definite mass but not a definite volume.it has a definite volume but not a definite shape.it has a definite shape but not a definite volume.

How many lone pairs of electrons are on the central atom of no3- and what is the molecular shape? one, trigonal planar zero, trigonal pyramidal zero, trigonal planar one, tetrahedral one, trigonal pyramidal