Qualitative Analysis Chem 1106 Lab 19 QA Process

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

• Na. Cl(aq) + Ag. NO 3(aq) Na. NO 3 (aq) + Ag. Cl ↓ • If this happens in the unknown the cation would be silver

QA • Ions react in predicable ways – Based on solubility rules form ppt – Forms gas – Color changes – p. H changes

QA • Salts are cations and anions • Cu. Cl • NH 4 CH 3 OO • Cu. SO 4

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 NH 4+ are soluble- not option on this lab why? • NO 3 - also not possible as all are soluble

QA • OH insoluble expect group 1, X reacts with NH 4 OH and Na. OH 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 • CO 3, PO 4 and S are insoluble except Group 1 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