1 / 7

Chemistry II

Chemistry II. Acid-Base PH and Titrations. Neutralization Reactions. Acid + Base salt + water NaOH + H 2 SO 4 Na 2 SO 4 + H 2 O. 2. 2 . Base with OH -. Acid with H +. Salt with metal from the base and the negative part of the acid.

kolton
Télécharger la présentation

Chemistry II

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemistry II Acid-Base PH and Titrations

  2. Neutralization Reactions • Acid + Base salt + water • NaOH + H2SO4 Na2SO4 + H2O 2 2 Base with OH- Acid with H+ Salt with metal from the base and the negative part of the acid Since 1 mole of and acid neutralizes 1 mole of a base, we can use this to find out unknown concentrations by a process of Titration.

  3. Titration Lab • Burette 0.0 ml 0.10 M KOH 50.0 ml 0.10 M KOH Stopcock Ma Va = Mb Vb Erlenmeyer flask Unknown Concentration of acid with know Volume Phenolphthalein indicator->

  4. Procedure: Titration • Prepare 200 ml of 0.10 M KOH • Grind up one 325 mg Aspirin tablet with a pistol and mortar. • Measure out 100 ml of distilled water and dissolve the Aspirin in the water in an Erlenmeyer flask. • Add 1.0 ml of Phenolphthalein (10 dps) • Pour slightly more than 50.0 ml of the 0.10 M KOH in the burette. • Turn on the stopcock and allow the solution to drip into an empty flask until the level at the top is at the “zero” mark.

  5. Continue • Place the Erlenmeyer flask with the aspirin and indicator under the tip of the burette and cautiously drip the KOH into the acid solution. • Place a magnetic stirring bar into the flask and put the apparatus on a magnetic stirring device. • When pink areas occur when the drop hits the acid solution, slow down the process because the end point is near. • Continue to drop the KOH into the Acid until the whole solution is pink.

  6. Titration Lab • Burette 50.0 ml 0.10 M KOH Scale reading = 0.0 ml Ma = Mb Vb Va = 0.10 x 20.0 ml 100.0 ml = 0.020 M 20.0 ml 0.10 M KOH Scale reading = 15.0 ml Volume of 0.10 M KOH = 20.0 ml Erlenmeyer flask Unknown Concentration of acid Volume = 100.0 ml Phenolphthalein indicator->

  7. Find the mass. Calculations • Aspirin ( Acetylsalicylic Acid C9H8O4 ) 0.020 mol/L X 0.100 L x 180.2 g/mol = 0.360 g of Aspirin O OH Size of Aspirin = 325 mg = 0.325 g O %Error = H – L x 100% H = 0.360 -0.325 x 100 0.360 = 9.7 % O Molar Mass = 180.2 g/mol

More Related