1

Identification of a SampleBased on Chemical Properties

Element Density (g/mL)

Ni 8.90

Cu 8.96

• Problem– Identify Components – Homogenous– Similar Densities– Distinguish The

Components Chemically

2

• Pennies

– Heterogeneous

• 5 Cent Coins – Homogeneous

• Nickel and Copper – Different Chemical

Properties– React Differently

Identification of a SampleBased on Chemical Properties

3

Ni2+

Ni2

+

Cu2

+

Cu2+

hydrogen peroxide and

vinegar

Heat

5 Cent Coin Solution

• Copper and Nickel – React With

H2O2 and HC2H3O

– Release Metal Ions

DO NOT POUR EXCESS BACK IN BOTTLE!!!

4

• Control Solutions – Aqueous

Solutions– Individual Metal

Ions– Observe

Individual Reactions

CuSO4

NiSO4

CuSO4 Cu2+ + SO4

2-

H2

O

NiSO4 Ni2+ + SO42-

H2

O

Control Solutions

5

Test

Solu

tions

Ammonia

Dimethyl-Glyoxime

PotassiumIodide

Metal Solutions

Nic

kel

Cop

per

5 c

en

t co

in

4 x 3 Well

Plate

• 2-3 Drops • Record Observations

6

• Control Solution Color

• Observation Color

• Most Dramatic Change?

Best Indicator

7

ammonia hydrogen peroxide

Surface Test

DO NOT POUR EXCESS REAGENTS or SAMPLES BACK IN BOTTLE!!!

• Paper Towel• Repeat if

Leakage• Blot with Paper

Towel (#13)

8

• Penny– Metal Ions

Released?

• NH4OH and H2O2 – Releases Metal Ions

• 5 Cent Coin– Metal Ions Released?

Surface Test

?AlloySurface?