Construct Ionic Equations Through Continuous Variation Method

NURUL ASHIKIN BT ABD RAHMAN (UPSI) -PEKA KIMIA 3-

Instrument : Laboratory ReportDate : 00 September 2012Title : Construct Ionic Equation

AIMTo construct a ionic equation for the formation lead (II) chromate (VI) based on the continuous variation reaction method.

PROBLEM STATEMENTHow to determine the ionic equation for precipitation of lead (II) chromate (VI)?

Hypothesis

The height of precipitate will increase with the volume of potassium chromate (IV) solution until

all the lead (II) nitrate has reacted.

VariableManipulated : Volume of potassium

chromate (IV)Responding : height of precipitateFixed : volume and molarity lead (II)

nitrate, molarity potassium chromate (IV),size of

test tube.

CHEMICAL

Potassium Chromate (IV) (0.5 M)

Lead (II) Nitrate(0.5 M)

APPARATUS

Test tube rack

Test tube

Rubber stopper

APPARATUS

Burette (50cm)

Ruler

Retort stand

FIGURE

PROCEDURE

REFER PRACTICAL BOOK

CHEMISTRY FORM 4

PAGE???

OBSERVATION

Test Tube 1 2 3 4 5 6 7 8

Volume of Pb(NO3)2 solution 0.5 M(cm3)

5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0

Volume of K2CrO4 solution 0.5 M(cm3)

1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Precipitate height (cm) 1.0

Colour of solution

Graph Height of precipitate (cm) against Volume K2CrO4 solution 0.5 M (cm3)

0 1 2 3 4 5 6 7 80

1

2

3

4

5

6 Height of precipitate (cm)

Volume K2CrO4 (cm3)

ANALYSING & INTERPRETING DATA

Volume of CrO42-

ions used to precipitate all the

Pb2+ ions

What is the volume of K2CrO4 solution (cm3) required to fully react with 5 cm3 Pb(NO3)2 solution ?

Mole K2CrO4 = ?Mole Pb(NO3)2 = ? n = MV

Ratio ?Ionic Equation?

DISCUSSION

Why the volume Pb(NO3)2 are fixed?Why some of solution remain yellow?and why

some of solution will be colourless?Refer page 123 practical book form 4

CONCLUSION

Ionic Equation ?Hypothesis accepted or not?