1 / 13

Performing a titration

Performing a titration. A bluffers guide!. Preparing a standard solution. Accurately weigh a weighing bottle, recording the mass Add approximately x g of your substance to the bottle. Re-weigh and record the mass Tip the substance into a 100cm 3 beaker.

karlyn
Télécharger la présentation

Performing a titration

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. Performing a titration A bluffers guide!

  2. Preparing a standard solution • Accurately weigh a weighing bottle, recording the mass • Add approximately x g of your substance to the bottle. • Re-weigh and record the mass • Tip the substance into a 100cm3 beaker

  3. Rinse out the weighing bottle with distilled water a couple of times. Add the washings to the beaker. (It is important all the solid goes into the beaker) • Pour about 25cm3 of distilled water into the beaker (but do not exceed half-full) • Stir with a glass rod until all the solid has dissolved

  4. Transfer the contents of the beaker into a 250cm3 volumetric flask, carefully, using a funnel. • Rinse the beaker and glass rod a couple of times, adding the washings to the flask, then wash the funnel twice as well. • This technique ensures all the solid is transferred.

  5. Add distilled water to the flask to about 1cm below the graduation mark • Using a clean pipette add distilled water until the bottom of the meniscus is just touching the graduation mark. • DO NOT EXCEED THIS MARK ON PAIN OF DEATH!!

  6. Stopper the flask, with the correct sized stopper, (Hint: Check this point before starting!!) and invert several times • You have now made a standard solution, the molarity of which you know exactly. • Having done all this correctly: stop and look very smug!!

  7. The titration itself

  8. Use a pipette and pipette filler to withdraw 25.0cm3 of standard solution from the volumetric flask and transfer it to a conical flask • Use a clean beaker to fill a burette with the solution that you are titrating with.

  9. Good practice includes • Not looking up at the beaker (This can be dangerous). You should be filling it from above, ie looking down on it!! • Ensure the tap is closed (Please!!) • Use an appropriate clamp!! • Use a funnel to perform this procedure • Run a little solution into the beaker to remove any air bubbles

  10. More ways to get an A* • Take the funnel out before recording the starting volume • It does not have to go to 0.0cm3 • Make sure you are aware you can record these volumes to 2dp, so therefore ensure you do record all volumes to 2dps!!! • Be consistent, always record to the bottom of the meniscus

  11. Couple more things • Use a white tile when doing the titration • Add the solution from the burette in small amounts, swirling all the while

  12. Finally • The end point will be an obvious sudden colour change. • Record the volume used and work out the volume used. This is your rough titration. • Do several more titrations until you achieve concordance (two readings within 0.1cm3). • Add the solution dropwise as the end point approaches, swirling at the same time.

  13. Indicators!!

More Related