Concentration

"Aim"
To make a dilution series to investigate concentration.

"Equipment"

• A potassium permanganate crystal, six large test tubes, tweezers, a plastic transfer pipette, a test tube rack, and 10 mL measuring cylinder.

"Method"
1. Place the six test tubes in a test tube rack. Label the rack with numbers 1 - 6.
2. Using the measuring cylinder, fill the test tube 1 with 10 ml of water. Fill the remaining test tube with 5 ml of water.
3. Using your tweezers, add a single crystal of potassium permanganate to test tube 1.
4. Gently shake the test tube until the crystal has dissolved.
5. Using the transfer pipette, carefully remove exactly 5 ml from the test tube 1 and pour it into test tube 2.
6. Rinse the transfer pipette thoroughly to ensure that no purple solution remains.
7. Gentle shake the test tube 2 and repeat the transfer progress, transferring exactly 5 ml of solution from the test tube 2 to test tube 3.
8. Rinse the pipette again and repeat the transfer process for test tube 4, 5 and 6.


Results:

You could see the labels, the higher the number is the thinner the colour is.
Every time we move the solution to another test tube its diluted by a little.

- Discussion -

First we picked up the solute (Potassium Permanganate) using the tweezers and we drop it in the first test tube. We mixed the solute and the solvent (Liquid) and we made a solution. Every time we put the solution to another test tube that has water, the Potassium Permanganate gets diluted (thinner). The most its concentrated is at test tube one.