Chem 162-2011 lecture 11

Chem 162-2011 lecture 11 - CHEMISTRY 162-2011 LECTURE 11...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
CHEMISTRY 162-2011 LECTURE 11 ANNOUNCEMENTS E-MAIL ATTENDANCE Sign in QUIZ Recitation quiz this week EXAMS Chem 162-2011 Lecture 11 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
PLAN FOR TODAY : CHAPTER 15 ACIDS AND BASES EQUILIBRIUM Ions as acids and bases The common ion effect Chem 162-2011 Lecture 11 2
Background image of page 2
pH [H + ] 14 Basic 1x10 -14 H 2 O + H 2 O H 3 O + + OH - K w = 1x10 -14 7 Neutral (e.g. H 2 O) 1x10 -7 K w = [H + ][OH - ] = 1 x 10 -14 pH + pOH = 14 K w = K a x K cb = K ca x K b = 1 x 10 -14 * *a & b = acid and base; ca & cb = conj. acid and conj. base; pK a + pK b = 14 0 Acidic 1x10 o A pH scale of 1 to 13 is common, but pH’s of -1 to +15 are possible. pH = -log[H + ] pH [H + ] [H + ] = 10 -pH pOH = -log[OH - ] [OH - ] = 10 -pOH pOH [OH - ] Henderson-Hasselbalch equation: pH = pK a + log([A - ]/[HA]) Chem 162-2011 Lecture 11 3 p H + O = 1 4 pH + pOH = 14 [H ][OH - ] = 1 x 10 -14 [ ] x 0 pOH = -log[OH - ] [OH - ] = 10 -pOH pH = -log[H + ] [H + ] = 10 -pH
Background image of page 3

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

View Full DocumentRight Arrow Icon
ET: Discuss strong acids and strong bases and the strengths of their conjugate bases and acids; practice both. Very weak base (i.e., not a base; K a Acid spectator ion)** ~10 9 HI + H 2 O H 3 O + + I - K cb = ~10 -23 ~10 8 HBr + H 2 O H 3 O + + Br - K cb = ~10 -22 ~10 6 HCl + H 2 O H 3 O + + Cl - K cb = ~10 -20 H 2 SO 4 + H 2 O H 3 O + + HSO 4 - K cb = ~0 HNO 3 + H 2 O H 3 O + + NO 3 - K cb = ~0 HClO 4 + H 2 O H 3 O + + ClO 4 - K cb = ~0 (HClO 3 + H 2 O H 3 O + + ClO 3 - )* K cb = ~0 *Strong, but not common, acid. Generally not considered as a strong acid. **These conjugate bases are known as “nominal bases”, i.e., a base by definition, but effectively not a base. All other acids are weak acids, e.g., HAc (acetic acid), H 2 SO 3 , RNH 3 + , BF 3 K a = 1.8x10 -5 HAc + H 2 O H 3 O + + Ac - K cb =5.6x10 -10 K a = 6.2x10 -10 HCN + H 2 O H 3 O + + CN - K cb =1.6x10 -5 Note that the stronger the acid, the weaker the CB; the weaker the acid, the stronger the CB. Arrhenius acid: Anything that provides a proton, e.g., HA, H 2 SO 3 , RNH 3 + LB Acid: Anything tending to give up a proton, e.g., HA, H 2 SO 3 , RNH 3 + STRONG BASES (Most Group 1A and 2A hydroxides [not HOH]) e.g. Very weak acid (i.e., not an acid; Base spectator ion) LiOH OH - + Li + NaOH OH - + Na + Mg(OH) 2 2OH - + Mg 2+ Ba(OH) 2 2OH - + Ba 2+ All other bases are weak bases, e.g., RNH 2 , CO 3 2- Arrhenius Base: Anything that provides an OH- group, e.g., NaOH LB Base: Anything that tends to react with a proton, e.g., NaOH, RNH
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 12

Chem 162-2011 lecture 11 - CHEMISTRY 162-2011 LECTURE 11...

This preview shows document pages 1 - 5. Sign up to view the full document.

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