Question

Determine [H3O⁺] and [OH⁻] concentrations (in M to two decimal places) for each:

a) Pure water at 10 degrees C (Kw=0.293 x 10⁻¹⁴)

Answer 1

The concentrations of H3O+ and OH− in pure water at 10 degrees Celsius, with a Kw of 0.293 x 10−14, are both 1.71 x 10−7 M, calculated by taking the square root of the Kw value.

Step-by-step explanation:

To determine the concentrations of H3O+ and OH− in pure water at 10 degrees Celsius with the water dissociation constant, Kw, being 0.293 x 10−14, we must recognize that pure water is neutral, meaning that the concentrations of H3O+ and OH− are equal. Therefore, to find each concentration, we take the square root of the Kw.

Using the provided Kw value at 10 degrees Celsius:

• Kw = [H3O+][OH−]
• Kw = 0.293 x 10−14

Since [H3O+] = [OH−], we can represent both concentrations with the variable x:

x = sqrt(Kw)

x = sqrt(0.293 x 10−14)

x = 1.71 x 10−7 M

Therefore, the concentration of H3O+ is 1.71 x 10−7 M and the concentration of OH− is also 1.71 x 10−7 M.