If element x bonds covalently with element y, then what must the electronegativity difference between x and y be for this bond to be nonpolar?

fire could start, buildings collapsing, and ash falling from the sky.

explanation:

this is because the buildings or plants could catch on fire and the buildings would most likely collapse. lastly ash would fall because all the burning would cause ash to fall from the sky.

hope this .

the ratio of the conjugate base to the acid required to attain the desired ph.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)