Titrations

Titrations

 

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Equivalence point = point where all the acid has been neutralized =  [HA] = 0

Half equilvance point = point where half the acid has been neutralized =   [HA] = [-A]  = pKa

 

12 10 8 pH pH = PK 6- half-eqUivålence point 4 2 .5 1 {OH-I buffered regions 1.5 equivalent fraction of base added

 

 

Buffers

-a buffer “buffers” the change in pH when H+ or –OH is added at  ±1 of the pKa of the buffer

 

14 13 12 11 10 9 8 pH 7 6 5 4 3 2 Buffered Solution Buffered reglon pH 6.3 H ++ HC03- Volume of base added

 

-the human body has three buffer systems: H2CO3, H2PO4, and albumin proteins

рка - 21 н,ро, [Г + Н:РО,• н,ро,- рка - 7.2 рка = 12,3 нсоз• - рКа : 6.4 рка 6.0

 

-a buffer is a 1:1 ratio of a weak  acid and its conjugate base

-it can be made by:

A. 1:1 ratio of a weak acid and its conjugate base

B. 2:1 ratio of a weak acid and a strong base

C. 2:1 ratio of a weak base and a strong acid

-ways B and C end up reacting to make A anyway

–you want a buffer with a pKa that is ±1 of the desired pH

 

17.1 Buffers

 

GENERAL CHEMISTRY Chapter 17: Buffers, Titrations, & Solubility Equilibria pH = + log [HA] Chadsprep.com

 

17.2 Titrations and Titration Curves

 

GENERAL CHEMISTRY Chapter 17: Buffers, Titrations, & Solubility Equilibria Chadsprep.com

 

 

 

 

Weak Acid titrated by Strong Base (pre-equivalence point)

 

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Weak Acid titrated by Strong Base (at equivalence point)

Titration of a weak acid with a strong base (continued) | Khan Academy

 

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Q つ つ - 0 ・ つ 0 っ 0 一 Q ・ 0 ー つ つ 一 つ ・ つ っ 0 一 0 ・ 0 0

 

HO 十 つ つ 土 っ ・ ・ ・ ・ し エ キ 一 つ 0 」 ュ っ 、 3 プ っ ・ 0 ミ 0 っ 了 っ ・ つ ト

 

о.очоо-Х о.очоо рои род, 5.33 04 фН&еоА:

 

 

Weak Acid titrated by Strong Base (after equivalence point)

 

Titration curve for the titration 14.0 12.0 10.0 8.0 6.0 4.0 2.0 o.o o.o djÂA/hat is t 100.0 of 0.200 M CH3COOH with 0.0500 M NaOH 50.0 PH fter the addition 300.0 0.0500 M of NaOH? CDIO co.osoo D. 3000 0.0150 —0. 0100 O • 0050 o • ooso oasoo -oŕł O.OIH 200.0 300.0 eoh: —109 OIH rnL ofO.0500 M NaOH

 

 

How To Calculate The pH of a Solution Without a Calculator – Acids and Bases

 

Estimate The pH 2] -log [3.3 x 10 No Calculator!!

 

MCAT Math Vid 9 – Antilogs in pH and pKa Without A Calculator

 

Leah4sci.com/mcat Presents : h ChLCOLAT0Q

 

 

equivalent weight = weight of acid required to release one mole of H+

 

 

 

 

Indicators:

 

Question 2 e When a weak base (R) is titrated with hydrochloric acid and an indicator (In) is present, the color change depends on the pH at which: Solution 41% o 21% o 29% @ C. D. pKa of In- = pKa of HA Hln is formed.

 

A titration is an experimental technique used to estimate the concentration of a substance (the analyte) using a substance of known concentration (the titrant). Titration setups commonly employ indicators, weak acids or bases that ionize within a known pH range to give a dramatic color change to the solution. The indicator's equilibrium reaction is shown below: Where Hln is the weak acid indicator and In- is the conjugate base, each a different color. The equilibrium of the indicator (and in effect, the color of the solution) depends on the pH of the solution. The indicator exists as Hln below its equivalence point and as In- above its equivalence point. When a weak base is titrated with hydrochloric acid, the solution starts off basic. When enough hydrochloric acid is added to reach the indicator's equivalence point, Hln will form, changing the solution's color. Therefore, we can conclude that the color change in this titration depends on the pH at which Hln is formed.

 

Indicators - Titration - MCAT Content

 

pH 10 weak aci strong ac 10 20 30 mL base added 40

 

Hydroxide ions react with remove mese hydrogen ions. The equilbrium position moves to replace tie lost hydrogen ions. Ljtnus ums blue.

 

 

 

Potentiometric titrations

 

-see Nicholas Price Principle and Problems in physical chemistry for biochemists

 

Potentiometric titrations (Principle, Procedure, Types, Ion-selective electrodes, applications)

 

POTENTIOMETRIC TITRATION

 

 

 

 

 

 

 

 

 

Factors effecting Acidity:

 

Main takeaways:

  1. stabalizing the conjugate base decreases the pKa and thus makes the molecule more likely to pop off a proton

 

this is accomplished by…

  1. delocalizating the charge or having the negative charge on an atom that wants a negative charge

 

  1. Electronegative atoms are more comfortable having a negative charge

less stable тоте stable

  1. Larger electronegative atoms are more comfortable having a negative charge (the proton/electron charge ratio is less effected in atoms with more electrons and protons)

less stable H3C morestable

Essential Organic Chemistry - ppt download

  1. Resonance: delocalizes the charge

5 Key Factors That Influence Acidity In Organic Chemistry

  1. Induction: EWD pull away negative charge and stablize the conjugate base

-also keep in mind that EDG destablize the conjugate base

  1. sp > sp2 > sp3 in conjugate base stability. The greater s character keeps electrons closer to the positive nucleus

H3C—CH3 less stable sp3 H2C—CH- more stable sp2 HCEC- most stable sp

 

Organic Chemistry – Ranking Acidity

 

 

June 6, 2024 | imperator