Which choice represents a pair of resonance structures? note that lone pairs have been omitted for clarity. view available hint(s) which choice represents a pair of resonance structures? note that lone pairs have been omitted for clarity.

a. o=c=o and o≡c−o
b. n≡n and br−br
c. n≡c− and n≡c−h
d. o=n−f and n=o−f

A. O=C=O and O≡C−O

Explanation:

Resonance:                                                                                                                

          When the electron distribution on the molecule become uneven like one molecule have more electron compare to other.Resonance occurs due to overlap of the orbitals.When electron flow through pi system then resonance occurs.

So the option A is correct.

A. O=C=O and O≡C−O

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

i think its 100.

hope this !