Chemistry - Chapter 16 Tro Chemistry A Molecular Approach 2...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 16 Tro, Chemistry: A Molecular Approach 2 Buffers • buffers are solutions that resist changes in pH when an acid or base is added • they act by neutralizing the added acid or base • but just like everything else, there is a limit to what they can do, eventually the pH changes • many buffers are made by mixing a solution of a weak acid with a solution of soluble salt containing its conjugate base anion Tro, Chemistry: A Molecular Approach 3 How Acid Buffers Work HA ( aq ) + H 2 O ( l ) ⇔ A − ( aq ) + H 3 O + ( aq ) • buffers work by applying Le Châtelier’s Principle to weak acid equilibrium • buffer solutions contain significant amounts of the weak acid molecules, HA – these molecules react with added base to neutralize it – you can also think of the H 3 O + combining with the OH − to make H 2 O; the H 3 O + is then replaced by the shifting equilibrium • the buffer solutions also contain significant amounts of the conjugate base anion, A −- these ions combine with added acid to make more HA and keep the H 3 O + constant Tro, Chemistry: A Molecular Approach 4 Common Ion Effect HA ( aq ) + H 2 O ( l ) ⇔ A − ( aq ) + H 3 O + ( aq ) • adding a salt containing the anion, NaA, that is the conjugate base of the acid (the common ion) shifts the position of equilibrium to the left • this causes the pH to be higher than the pH of the acid solution – lowering the H 3 O + ion concentration Tro, Chemistry: A Molecular Approach 5 Practice - What is the pH of a buffer that is 0.14 M HF (p K a = 3.15) and 0.071 M KF? Tro, Chemistry: A Molecular Approach 6 Practice - What is the pH of a buffer that is 0.14 M HF (p K a = 3.15) and 0.071 M KF?...
View Full Document

{[ snackBarMessage ]}

Page1 / 18

Chemistry - Chapter 16 Tro Chemistry A Molecular Approach 2...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online