The Invisible Ink Task
You are a lab technician for a toy company. Your company has developed and patented a nontoxic form of invisible ink. When you write on paper with the liquid and let it dry, the writing becomes invisible (it becomes visible, again, when you apply another chemical to it). Only you and your team of scientists know that the ink is actually a solution of cobalt chloride in water. Cobalt chloride is expensive. Water is less expensive, and the lab has plenty of water.
Prepare a batch of 0.7 L (liters) of cobalt chloride solution for your company’s next shipment. The concentration of the solution should be between 1.995 and 2.005 mol/L.
Simulation Quick Tour
- Add WaterPull handle to the right
- Add SolidShake left & right
- Add SolutionSelect and squeeze top of pipette
- Select SoluteClick drop down & select
- Measure ConcentrationDrag meter probe into liquid
- Drain WaterClick on handle & pull right
- Remove SoluteClick on button
- EvaporateDrag slider to the right
- ResetClick on arrow button
Prepare a batch of 0.7L(liters) of Cobalt Chloride solution.
The concentration of the solution should be between 1.995 and 2.0005 mol L.
- Try not to waste cobalt clhoride - it's expensive!
- There is plenty of water available - it's cheap!
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Visit phet.metacog.com/InvisibleInk and perform the task as many times as you'd like
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