Concentration – Interactive PhET Simulation

Explore concentration and solutions

The concentration of a solution depends on the amount of dissolved solute compared with the volume of solution.

This interactive PhET simulation allows you to investigate how concentration changes when you add solute, add or remove water, or evaporate solvent. You can also explore what happens when a solution becomes saturated and no more solute can dissolve.

Make predictions before changing the solution. Decide whether each change should increase, decrease or leave the concentration unchanged, and then use the simulation to test your reasoning.

Concentration is provided by PhET Interactive Simulations, University of Colorado Boulder, and is used under the CC BY-NC 4.0 licence.

Try these challenges

1. Add more solute
Start with a solution of known volume and add more solute. Predict what will happen to the concentration before checking the concentration meter.

2. Dilute the solution
Add water without adding any more solute. What happens to the concentration? Explain why the amount of solute has not changed even though the concentration has.

3. Evaporate some water
Remove solvent by evaporation. Predict what will happen to the concentration. Explain your result in terms of the amount of solute and the volume of solution.

4. Remove some solution
Prepare a uniform solution and then drain some of it away. Before doing so, predict what will happen to its concentration. Does removing some solution necessarily make the remaining solution more dilute?

5. Reach saturation
Continue adding solute. Eventually no more will dissolve. What do you observe? What does saturated solution mean at that temperature?

6. Compare different solutions
Choose different solutes and investigate how much of each can dissolve. Do all substances have the same solubility?

7. Think quantitatively
Suppose the amount of dissolved solute remains constant but the solution volume is doubled. Predict what happens to the concentration. What if the volume is halved?

The key question

Keep asking:

Has the amount of dissolved solute changed, has the volume of solution changed, or have both changed?

That distinction is the key to predicting how the concentration will change.

 
 
 
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