A buffer that contains 0.578 M base, B, and 0.263 M of its conjugate acid, BH , has a pH of 8.97. What is the pH after 0.0020 mol of HCl is added to 0.250 L of this solution?

pH = 8.95

Explanation:

A buffer follows H-H equation:

pH = pKa + log [B] / [BH⁺]

Where pH is pH of the buffer: 8.97

pKa is a constant of the buffer (Our incognite)

[B] is molar concentration -or moles- of the base: 0.578M

[BH⁺] is molar concentration -or moles- of conjugate acid: 0.263M

pH = pKa + log [B] / [BH⁺]

8.97 = pKa + log [0.578M] / [0.263M]

8.628 = pKa of the buffer

0.250L contains:

[B] = 0.578M * 0.250L = 0.1445 moles of B

[BH⁺] = 0.263M * 0.250L = 0.06575 moles of BH⁺

When HCl is added, B is consumed and BH⁺ is produced as follows:

HCl + B → BH⁺ + Cl⁻

That means moles of each species after the addition of HCl is:

[B] = 0.1445 moles - 0.0020moles = 0.1425moles

[BH⁺] = 0.06575 moles + 0.0020moles = 0.06775moles

Replacing in H-H equation, pH is:

pH = 8.628 + log [0.1425moles] / [0.06775moles]

pH = 8.95

Ithink the answer is 56.

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.