Page 39 - Curriculum Visions Dynamic Book

 Chromium III oxide
This green substance is used as a pigment for paint.
 This is a yellow precipitate of lead chromate. It was prepared
by adding yellow potassium chromate solution to colourless lead nitrate solution. The beaker is sitting on a magnetic stirrer that spins the plastic coated metal mixer (sometimes called a “magnetic flea”) in the bottom. This thoroughly stirs the chemicals. In this case the potassium chromate solution was added about a second before the picture was taken.
Beaker
Solution of lead nitrate
As soon as the solution of potassium chromate is added
it is mixed with the solution of lead nitrate and forms a yellow precipitate of lead chromate.
Magnetic flea
Motor driving the magnet
EQUATION: Reaction of potassium chromate and lead nitrate
Potassium chromate + lead II nitrate ➪ lead chromate + potassium nitrate K2CrO4(aq) + Pb(NO3)2(aq) ➪ PbCrO4(s) + 2KNO3(aq)
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