polyprotic phosphoric acid pka

biochemistry: Experiment 1 : Acid Base Experiment

16 03 2013The purpose of acid base laboratory experiment was to determine equivalance points pKa points for a strong acid HCl titrated with a strong base NaOH using a drop approach in order to determine completely accurate data The pH is measured every time 1ml of NaOH added The pKa of acetic acid theoretically is at 4 76 Using a concentration of 0 1M NaOH we had the largest NaOH

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POLYPROTIC ACIDS AND BASES: Very important!

POLYPROTIC ACIDS AND BASES: Very important! -- acids that can lose and bases a1 = 7 2 x 10-3 increasing H 2PO 4 - (aq) ⇌ H+ (aq) + HPO 4 2-(aq) K a2 = 6 3 x 10-8 acid HPO 4 2-(aq) ⇌ H+ (aq) + PO 4 3-(aq) K a3 = 4 2 x 10-13 strength Note: (i) K a1 K a2 K a3 Always true for polyprotic acids i e each ionization step is more difficult because it is more difficult to remove H+ from

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PH Titration Essay Example

Introduce the idea of a polyprotic acid and illustrate how phosphoric acid (H3PO4) can lose multiple protons What shape should students expect for the titration of a polyprotic acid with strong base? H3PO4(aq) + HO!(aq) ! H2PO! 4 (aq)+H2O(l) etc Lab Logistics

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Ionic strength and the dissociation of acids

polyprotic acid having a charge z on the fully protonated form of the acid is pKA(MIX) n = pKA(THERM) n + A V'I(2z - 2n + 1) (1 + W) (12) Buffer solutions and ionic strength Before discussing the output from the programs ACIDS and IOS it is worth considering the consequences of ignoring ionic strength in the preparation of a buffer solution Suppose a phosphate buffer is being prepared by

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Acid_dissociation_constant

An acid dissociation constant denoted by K a is an equilibrium constant for the dissociation of a weak acid According to the Brnsted-Lowry theory of acids and bases an acid is a proton donor (HA where H represents an acidic hydrogen atom) and a base is a proton acceptor In aqueous solution water can function as a base as in the following general example

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Acid

phosphoric acid (H 3 PO 4) 7 1 x 10-3 : citric acid (C 6 H 7 O 8) 7 5 x 10-4 : acetic acid (CH 3 CO 2 H) 1 8 x 10-5 : boric acid (H 3 BO 3) 7 3 x 10-10 : water (H 2 O) 1 8 x 10-16 : The table above provides us with the basis for understanding the difference between strong acids and weak acids Think about the reaction between a very strong acid

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Buffer Calculator

The strength of an acid is measured using a pKa value or the negative log of the acid dissociation constant A lower pKa value indicates a stronger acid and the greater its ability to donate a proton or fully dissociate in water The pKa predicts what a molecule will do at a specific pH and is constant for each type of molecule

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Acids and Bases

Acids and Bases Background Material - Text: through Section 5 1 CHEM 462 T Hughbanks Quick Review - To be discussed only briefly in class Brnsted acids bases: proton donors and acceptors in water: true nature of "H+(aq)" is complicated but certainly H 3O+ is the simplest realistic species clusters surrounding H 3O+ vary in size depending on circumstances (counterions ionic strength

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What Is Polyprotic Acid? Chemistry Definition

Orthophosphoric acid (H 3 PO 4) is a triprotic acid Successive deprotonations yield H 2 PO 4- HPO 4 2- and PO 4 3- In this acid the positions of the original three hydrogen atoms are equivalent on the molecule but removal of subsequent protons becomes less energetically favorable

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Buffer Calculator

The strength of an acid is measured using a pKa value or the negative log of the acid dissociation constant A lower pKa value indicates a stronger acid and the greater its ability to donate a proton or fully dissociate in water The pKa predicts what a molecule will do at a specific pH and is constant for each type of molecule

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Polyprotic Acids and Bases

1 Polyprotic Acids and Bases Polyprotic Acids and Bases According to Brnsted and Lowry an acid is a proton donor and a base is a proton acceptor This idea of proton donor and proton acceptor is important in understanding monoprotic and polyprotic acids and bases because monoprotic corresponds to the transfer of one proton and polyprotic refers to the transfer of more than one proton

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Buffer Calculator

What is pKa? The strength of an acid is measured using a pKa value or the negative log of the acid dissociation constant A lower pKa value indicates a stronger acid and the greater its ability to donate a proton or fully dissociate in water The pKa predicts what a molecule will do at a specific pH and is constant for each type of molecule

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14 3 Relative Strengths of Acids and Bases – Chemistry

14 3 Relative Strengths of Acids and Bases Learning Objectives By the end of this section you will be able to: Assess the relative strengths of acids and bases according to their ionization constants Rationalize trends in acid–base strength in relation to molecular structure Carry out equilibrium calculations for weak acid–base systems We can rank the strengths of acids by the extent

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Phosphoric acid react with sodium hydroxide

Phosphoric acid react with sodium hydroxide to produce sodium hydrogen phosphate and water Phosphoric acid and sodium hydroxide - diluted solutions Find another reaction Our channel Thermodynamic properties of substances The solubility of the substances Periodic table of elements

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Acids Bases

B/L Acid/Base Strength Relationships Strongest Acids = Weakest Conjugate Bases Strongest Bases = Weakest Conjugate Acids Weak Acids = Weak Conjugate Bases Weak Acids/Bases have pKa/b between 2 12 Weak Acids Weak Bases HC 2H 3O 2 10% + H 2 OC 2H 3O 2 + H 10% NH 3 + H 2O 4 + OH 3 23 pKa pKb of Conjugate Acid/Base Pairs-9 0 7 14 Strong Weak Very Weak HCl Cl

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Triprotic Titration Interactive Model and Data Analysis

Triprotic Titration Interactive Model and Data Analysis Templates OpenOffice Calc and Microsoft Excel Versions Screen shot of OpenOffice version Click to see larger graphic An interactive model of the titration curve of a weak triprotic acid titrated by a strong base For a triprotic acid that is a quintic equation - too complex to evaluate by hand but easy for a spreadsheet to handle By

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Using paulings rules to predict the pKa of oxoacids?

Pauling's rules for pKa values are really simple namely: 1 the pKa of an acid (O) p E(OH) q is pKa = 8-5p 2 the successive pKa's go up by 5 per ionisation (i e for the second third fourth proton etc ) So for H2SeO4: 1 first rewrite it in the form used above: O 2 Se(OH) 2 2 calculate the pKa by Pauling's rules: pKa = 8 - 5*2 = -2

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Using Excel to Fit a Titration Curve

Using Excel to Fit a Titration Curve * An Excel spreadsheet has been developed to help you fit a theoretical titration curve to the pH vs volume data that you collection in your pH titration experiment The spreadsheet will enable you to determine the end point(s) of the titration as well as the pK a (s) of your unknown acid This document is

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