chm 101/102 laboratory manual unknown solid identification general chemistry 101/102 laboratory...
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CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
General Chemistry 101/102General Chemistry 101/102Laboratory ManualLaboratory Manual
University of North Carolina at WilmingtonUniversity of North Carolina at Wilmington
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• PurposePurpose To identify a solid substance based on its physical To identify a solid substance based on its physical
and chemical properties.and chemical properties.
• Safety ConsiderationsSafety Considerations Exercise caution when handling the NaOH and Exercise caution when handling the NaOH and
HCl solutions. These are fairly concentrated HCl solutions. These are fairly concentrated solutions and may cause burns.solutions and may cause burns.
Dispose of all liquid wastes in the waste jar in the Dispose of all liquid wastes in the waste jar in the hood. Place solid wastes in the solid waste hood. Place solid wastes in the solid waste container.container.
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• ProcedureProcedure Prepare a saturated solution of your Prepare a saturated solution of your
unknown. Use this solution whenever a unknown. Use this solution whenever a test calls for using the test calls for using the unknown solutionunknown solution..
saturatedsolution
Test 1: Record the Test 1: Record the colorcolor of your unknown of your unknown solid and solution.solid and solution.
Test 2: Record the Test 2: Record the odorodor of your unknown of your unknown solid and solution.solid and solution.
http://www.nabt.org/sup/publications/nlca/nlcapdf/11NLCAchp9.pdf
Test 3: Add 10 drops of 1 M NaOH to 10 Test 3: Add 10 drops of 1 M NaOH to 10 drops of your unknown solution. Gently drops of your unknown solution. Gently warm the test tube to check for the warm the test tube to check for the odorodor of of ammonia.ammonia.
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• ProcedureProcedure Test 4: Test the Test 4: Test the acid/base propertiesacid/base properties of your of your
unknown solution with litmus paper.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 5: Clean a wire test loop and conduct a flame test using your solid unknown.test using your solid unknown.
clean wire has only faint yellow flame
use small amount of solid for flame test
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• ProcedureProcedure Test 5 (cont.): Test 5 (cont.): Identify the cationIdentify the cation present in the flame present in the flame
test.test.
NaNa++ flame testflame test
CaCa2+2+ flame testflame test
LiLi++ flame testflame test
KK++ flame testflame test
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• ProcedureProcedure Test 6: Add 10 drops of 6M HCl to a Test 6: Add 10 drops of 6M HCl to a
small amount of the solid unknown to test small amount of the solid unknown to test for the presence of the carbonate ion.for the presence of the carbonate ion.
Test 7: Add 2 drops of 0.1 M AgNOTest 7: Add 2 drops of 0.1 M AgNO33 to a to a
small amount of the unknown solution in a small amount of the unknown solution in a spot plate to test for the presence of spot plate to test for the presence of Cl Cl --, Br , Br --, I, I--, or CO, or CO33
2-2- ions. ions.
AgClAgCl AgBrAgBroror
AgIAgI
AgAg22COCO33
CHM 101/102CHM 101/102
Laboratory ManualLaboratory ManualLaboratory Manual
Unknown Solid IdentificationUnknown Solid Identification
• ProcedureProcedure Test 8: Add 2 drops of 0.1 M Pb(NOTest 8: Add 2 drops of 0.1 M Pb(NO33))22 to a small to a small
amount of the unknown solution in a spot plate to test amount of the unknown solution in a spot plate to test for the presence of Cl for the presence of Cl --, Br , Br --, I, I--, or CO, or CO33
2-2- ions. ions.
PbClPbCl22oror
PbBrPbBr22
PbIPbI22 PbCOPbCO33