Calculate the [H₃O⁺] of each aqueous solution with the following [OH⁻]: a. baking soda, 1.0 x 10⁻⁶ M

Verified step by step guidance

1. Identify the relationship between [H₃O⁺] and [OH⁻] using the water dissociation constant, Kw. The equation is Kw = [H₃O⁺][OH⁻], where Kw at 25°C is 1.0 x 10⁻¹⁴.
2. Rearrange the equation to solve for [H₃O⁺]: [H₃O⁺] = Kw / [OH⁻].
3. Substitute the given [OH⁻] value into the equation: [H₃O⁺] = (1.0 x 10⁻¹⁴) / (1.0 x 10⁻⁶).
4. Perform the division to find the [H₃O⁺].
5. Ensure the units are consistent and the calculation is correct, confirming the [H₃O⁺] value.

Key Concepts

pH and pOH Relationship

The pH and pOH of a solution are related through the equation pH + pOH = 14 at 25°C. This relationship allows us to calculate one from the other. Since pH measures the concentration of hydrogen ions [H₃O⁺] and pOH measures the concentration of hydroxide ions [OH⁻], knowing one enables the determination of the other.

Ion Product of Water

The ion product of water (Kw) is a constant at a given temperature, defined as Kw = [H₃O⁺][OH⁻]. At 25°C, Kw is 1.0 x 10⁻¹⁴. This relationship is crucial for calculating the concentration of hydronium ions when the concentration of hydroxide ions is known, as it allows for the determination of [H₃O⁺] from [OH⁻].

Concentration Units in Chemistry

Concentration in chemistry is often expressed in molarity (M), which is moles of solute per liter of solution. Understanding how to manipulate these units is essential for calculations involving [H₃O⁺] and [OH⁻]. In this context, knowing the molarity of hydroxide ions allows for the calculation of hydronium ion concentration using the relationships defined by pH, pOH, and Kw.