Calculate the concentration of H3O+ in a solution that contains 6.25 × 10-9 M OH- at 25°C. Identify the solution as acidic, basic, or neutral.

[OH⁻] = 1.60 × 10⁻⁶ M

Basic

Explanation:

Step 1: Given data

Concentration of H₃O⁺: 6.25 × 10⁻⁹ M

Step 2: Calculate the concentration of OH⁻

We will use the following expression.

Kw = [H₃O⁺] × [OH⁻] = 1.00 × 10⁻¹⁴

[OH⁻] = 1.00 × 10⁻¹⁴ / 6.25 × 10⁻⁹ = 1.60 × 10⁻⁶ M

Step 3: Calculate the pH

We will use the following expresion.

pH = -log [H₃O⁺] = -log (6.25 × 10⁻⁹) = 8.20

Since the pH > 7, the solution is basic.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.