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Titrations......help you see neutralization reactions. Acid and base react to form salt and water....determine concentration of a solution by reacting.

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Presentation on theme: "Titrations......help you see neutralization reactions. Acid and base react to form salt and water....determine concentration of a solution by reacting."— Presentation transcript:

1 Titrations......help you see neutralization reactions. Acid and base react to form salt and water....determine concentration of a solution by reacting it with a solution with a known concentration.

2 Types of Titrations Strong Acid with Strong Base Strong Base with Strong Acid Weak Acid with Strong Base Weak Base with Strong Acid Weak Acid with Weak Base

3 Standard Procedure... 1. Prepare standard (titrating solution): it is of known concentration Exactly mass This information will be crucial to all other calculations. Rinse buret So there is no contamination from other substances. Fill buret 2. Unknown: in beaker or flask beneath buret indicator is added Known volumes of standard are added to it.

4 3. Record data... either volume of standard Time pH Continue until you reach the stoichiometric point: Moles H + from acid = moles OH - from base. Stoichiometric point is the equivalence point pH = pKa End point – one drop of base beyond stoichiometric/equivalence point; color changed; on graph:midpoint of most vertical part of graph = exact midpoint; rate of pH diminishes; 4. REPEAT

5 http://www.shsu.edu/%7Echm_t gc/sounds/titrate.mov

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7 Vocabulary equivalence point - when the moles of acid or base added equals the moles of acid or base which are present midpoint - when the moles of acid or base added is 1/2 the moles of acid or base which are present indicator - a dye used to indicate when the reaction is complete. It changes color at the equivalence point.

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9 Important Regions At time = 0, before the titration begins Before the equivalence point At the midpoint At the equivalence point After the equivalence point

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11 Standardizing a Solution... Why is there a need to standardize NaOH? Mole ratio between KHP and NaOH should be 1:1 (at equivalence point of titration)

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15 Strong Acid / Strong Base

16 Assume 100% ionized in aqueous solution.

17 Indicators...

18 Compare Weak/Strong Acid

19 Indicators...

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21 Diprotic Acid Graph shows a steep rise or endpoint for each of the protons in the acid.

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29 Weak Acid/Strong Base

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