70 likes | 380 Views
Unknown Solid Identification. General Chemistry 101/102 Laboratory Manual University of North Carolina at Wilmington. Unknown Solid Identification. Purpose. To identify a solid substance based on its physical and chemical properties. Safety Considerations.
E N D
Unknown Solid Identification General Chemistry 101/102Laboratory ManualUniversity of North Carolina at Wilmington
Unknown Solid Identification • Purpose • To identify a solid substance based on its physical and chemical properties. • Safety Considerations • Exercise caution when handling the NaOH and HCl solutions. These are fairly concentrated solutions and may cause burns. • Dispose of all liquid wastes in the waste jar in the hood. Place solid wastes in the solid waste container.
Prepare a saturated solution of your unknown. Use this solution whenever a test calls for using the unknown solution. saturatedsolution • Test 2: Record the odor of your unknown solid and solution. http://www.nabt.org/sup/publications/ nlca/nlcapdf/11NLCAchp9.pdf Unknown Solid Identification • Procedure • Test 1: Record the color of your unknown solid and solution. • Test 3: Add 10 drops of 1 M NaOH to 10 drops of your unknown solution. Gently warm the test tube to check for the odor of ammonia.
Test 4: Test the acid/base properties of your unknown solution with litmus paper. bases turn red litmus blue acids turn blue litmus red • Test 5: Clean a wire test loop and conduct a flame test using your solid unknown. use small amount of solid for flame test clean wire has only faint yellow flame Unknown Solid Identification • Procedure
Test 5 (cont.): Identify the cation present in the flame test. Na+flame test Ca2+flame test Li+flame test K+flame test Unknown Solid Identification • Procedure
Test 6: Add 10 drops of 6M HCl to a small amount of the solid unknown to test for the presence of the carbonate ion. • Test 7: Add 2 drops of 0.1 M AgNO3 to a small amount of the unknown solution in a spot plate to test for the presence of Cl -, Br -, I-, or CO32- ions. AgBrorAgI Ag2CO3 AgCl Unknown Solid Identification • Procedure
Test 8: Add 2 drops of 0.1 M Pb(NO3)2 to a small amount of the unknown solution in a spot plate to test for the presence of Cl -, Br -, I-, or CO32- ions. PbCl2orPbBr2 PbI2 PbCO3 Unknown Solid Identification • Procedure