Qualitative Analysis Chem 1106 Lab 19

QA Process of determining if a chemical is present or not NOT how much only the presence Changed form 5 to 3 anions and 3 cations in the unknown

QA 2 lab periods to do this Independent work Individual data and report

QA First week is a process of data collection Run many experiments and write observations The more accurate the data collection the better Think about what could be the compound that would be causing the change. Since this is the information you need for the unknown

NaCl(aq) + AgNO3(aq)  NaNO3 (aq) + AgCl ↓ If this happens in the unknown then the cation would be silver

QA Ions react in predicable ways –Based on solubility rules form ppt –Forms gas –Color changes –pH changes

QA Salts are cations and anions CuCl NH4CH3OO CuSO4

QA Ay 12 salts to create a database A reaction matrix Ions and cations are listed in your handout That are possiblities

QA Group 1 soluble, ppt of alkali metals will not occur why? All NH4+ are soluble- not option on this lab why? NO3- also not possible as all are soluble are soluble

QA OH insoluble expect group1, X reacts with NH4OH and NaOH forms ppt the X can not be alkali metal so NA ruled out. Cl, Br, I are soluble, except Ag, Hg, Pb If you to X add Cl with HCl white ppt forms has to be one of the three cations and Cl is not one of the anions CO3, PO4 and S are insoluble except Group1 no info because both are out Sulfites soluble, Ca and Ag in soluble

QA Ba and Pb are insoluble, since the cation is Pb or Ag then sulfites are not our unknown You have only the pipets given do not mix them up rinise them well with DI water before starting Use the matrix as your plan Work carefully and records all information

QA Second week NO collaboration from any source except your notes from the matrix and your knowledge of chemsity

QA Day two 4 stock solutions –Determine the cations –All in water so must be water soluble Unknowns So think today.