Explanation:
Ions are the species that contain a charge either positive or negative charge.
When a neutral atom loses an electron then it acquires a positive charge. Whereas if a neutral atom gains an electron then it acquires a negative charge.
For example, 
means there is +1 charge on sodium.
But if a compound does not contain any charge then it means the compound is neutral.
For example, in the compound 
there is no charge so, this compound is neutral.
Hence, we can conclude that no ions are present in a sample of .
Answer:
<em>The flow of thermal energy in a system, at constant atmospheric pressure AND at thermodynamic standard temperature and pressure.</em>
Answer:
D
Explanation: An exothermic change is Because it has heat.
When two atoms of Florine combines, they share an electron pair to complete it's octet. This result is formation of single bond between two fluorine atoms. This process is exothermic in nature, and hence, heat is liberated during the process of bond formation. <span />
Answer:
3.62x10⁻⁷ = Kb
Explanation:
The acid equilibrium of a weak acid, HX, is:
HX + H₂O ⇄ X⁻ + H₃O⁺
Where Ka = [X⁻] [H₃O⁺] / [HX]
And basic equilibrium of the conjugate base, is:
X⁻ + H₂O ⇄ OH⁻ + HX
Where Kb = [OH⁻] [HX] / [X⁻]
To convert Ka to Kb we must use water equilibrium:
2H₂O ⇄ H₃O⁺ + OH⁻
Where Kw = 1x10⁻¹⁴ = [OH⁻] [H₃O⁺]
Thus, we can obtain:
Kw = Ka*Kb
Solving for Kb:
Kw / Ka = Kb
1x10⁻¹⁴ / 2.76x10⁻⁸ =
3.62x10⁻⁷ = Kb
