What is a consequence of electron-pair repulsion around an atom?
A. The atoms sharing the electron pairs will be lost as ions.
B. The atoms sharing the electron pairs will be pushed together.
c. The atoms sharing the electron pairs will spread out around the
central atom
D. The atoms sharing the electron pairs will form attractions with
other atoms.

okay yes , aha.

pure substance: iron,copper

impure substance: water,charcoal

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

the dissolution of polymer can be thermodynamically described in 2 steps.