Answer:
A. They are equal.
B. The ratio of ions to molecules is 1 to 2.78× 10⁸.
Explanation:
A. Concentration of ions
In pure water, [H₃O⁺] = [OH⁻] = 1.00 × 10⁻⁷ mol·L⁻¹.
The concentration of hydroxide ions equals that of hydronium ions.
B. Ratio of ions to molecules
Assume you have 1 L of pure water.
[tex]\text{Moles of water} = \text{1000 g} \times \dfrac{\text{1 mol}}{\text{18.02 g}} = \text{55.49 mol}[/tex]
You have 1.00× 10⁻⁷ mol·L⁻¹ [H₃O⁺] and 1.00× 10⁻⁷ mol·L⁻¹ [OH⁻], so you have 2,00 mol·L⁻¹ of ions.
The ratio of concentrations is
[tex]\dfrac{\text{[Ions]}}{\text{[Molecules]}} = \dfrac{2.00 \times 10^{-7}}{55.49} = \dfrac{ 3.60 \times 10^{-5}}{1} = \mathbf{\dfrac{1}{2.78 \times 10^{8}}}[/tex]
