1 / 11

Experiment 4

Experiment 4. Observing Chemical Reactions. Chemistry Department UCC 1 st Year Practicals. Objectives. Test your powers of observation Investigate the reaction of four inorganic chemicals with five common laboratory chemicals

deana
Download Presentation

Experiment 4

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. Experiment 4 Observing Chemical Reactions Chemistry Department UCC 1st Year Practicals

  2. Objectives • Test your powers of observation • Investigate the reaction of four inorganic chemicals with five common laboratory chemicals • Devise a system for determination of the presence of these compounds in a mixture of unknown composition • Apply this system to an unknown mixture containing two different metal salts

  3. Experimental • Four compounds: AgNO3, Mg(NO3)2, Sr(NO3)2, Al(NO3)3 • Five chemicals: HCl, H2SO4, HNO3, NH3, NaOH • You will react each laboratory chemical with each compound and record your observations • Add all chemicals dropwise at all times

  4. Table of Observations

  5. First test • 0.5 mL of silver nitrate in a test tube and add 3 drops of HCl • If you observe nothing then record this also • A negative result is as important as a positive result

  6. Second and third tests • Repeat the first test using sulfuric acid, then nitric acid in place of hydrochloric acid • Record your observations in the table • Record any effervescence, colour change, precipitation

  7. Fourth test • Add NH3 solution - a ppt may form • Redissolves after more NH3 added? • If redissolves, add nitric acid until ppt reforms • Keep adding nitric acid dropwise • Does ppt redissolve again? • Record all observations

  8. Fifth test • Add 1 drop of NaOH and wait for 30 seconds • If reaction has occurred add NaOH • If ppt redissolves add nitric acid until a ppt is formed • Add more nitric acid, does ppt dissolve again?

  9. Identifying unknown mixture • Having performed all tests on all four compounds devise a method of identifying presence of one of the compounds in the unknown • Firstly test the method on a solution of all four compounds • Identify which two metal compounds are present in your unknown mixture A-F

  10. Identifying unknown mixture • Do all the steps of every test • Note the letters of your unknown solutions in your write up • Each unknown contains two metal salts • Must identify both salts in the unknown

  11. Report • Include your table of observations • Method of identification of metal ions in the unknown solution • Brief discussion & conclusions • Read Exp. 5 and Exp. 6a for next week

More Related