Distallation - Chemicals & chaos

                                                               Distillation

Recap:  Last lesson we learnt that the process of evaporation is when a liquid turns into a gas. So we can separate a solution, by evaporating away the solvent to learnt a solute (solid). 

But what if we want to collect gas?? When we trap the gas and turn it back into a liquid this is called condensation.

What is it?

• Evaporation: heating a liquid, turns to a gas
• Condensation: cooling down a gas, turn into a liquid.

Experiment:                                  Separating a mixture using distillation

Aim: To separate a solute from a solvent in a solution using distillation.

Equipment: 

• A solution of saltwater
• Conical flask
• Heatproof mat
• A delivery tube and bung
• Bunsen burner
• Tripod
• Gauze mat 
• Retort stand
• Boss head and clamp
• Boiling tube

Method:

1. Set up the equipment as shown in the diagram
2. Add approximately 50 ml of saltwater to your conical flask
3. Light your bunsen burner. Open the air hole and gently push the bunsen burner under the tripod
4. Heat the solution until most of the solvent has been evaporated. Turn off your bunsen burner.

Hypothesis: When the coke is heated the sugar will solidify and stay in the flask and the liquid will be evaporated and travel all the way to the test tube and cool.

Observations: As soon as we put the Bunsen burner on the coke was already boiling, when the coke started to evaporate it was transferred through the bung and into the tube where it cools and turns into clear brown liquid.

Conclusion: Coke Zero has had less dissolved substances, when normal coke had more dissolved solids which was sugar.

Serial Dilution

 Aim: To make a dilution series to investigate concentration.

Hypothesis: I think that the potassium permanganate will slowly dilute as we tip 5 ml of every test tube into the next test tube.

Equipment:

• A potassium permanganate crystal
• Six large test tube
• Tweezers
• A plastic transfer pipette
• A test tube rack
• 10 ml measuring cylinder

Method:

1. Place 6 test tubes in a test tube rack. Label the rack with numbers 1-6
2. Using the measuring cylinder, fill 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 test tube 1 and pour it into test tube 2
6. Rinse the transfer pipette thoroughly to ensure that no purple solution remains
7. Gently shake test tube 2 and repeat the transfer process, transferring exactly 5 ml of solution from test tube 2 to test tube 3.
8. Rinse the pipette again and repeat the transfer process for test tubes 4, 5 and 6.

Discussion:

Which was most dilute? Test tube 6

Least diluted? Test tube 1

Most concentrated? Test tube 1

Least concentrated? Test tube 6

How fo you know? With the most diluted the colour of the liquid has less colour to it and the most concentrated is the brightness of the liquid.

Filtration Experiment

Aim: To separate a solution from a precipitate (precipitate is the name for a solid that forms in a liquid during a chemical reaction.) 

 

Solvent - Thing doing the dissolving (liquid)

Solute - Thing being dissolved (solid)   

Solution - A mixture that is formed.

Filtration - Separates particles based on size.

Filtrate - Liquid after it has been filtered.

Mixture - 2 or more substances together

Solubility - Ability to dissolve.

Hypothesis: What do you think will happen 

Equipment:

• Copper sulfate
• Conical flask
• Stirring rod
• 200ml beaker
• Funnel
• Filter paper

Method: 

1. Pour approximately 50ml of copper sulfate solution into a beaker. 
2. Add the same volume of sodium carbonate solution. A reaction will happen, you should see a cloudy blue precipitate form. Called copper carbonate.
3. Watch demo then fold filter to fit inside the funnel.
4. Place the funnel with the filter paper inside of it, into the mouth of a conical flask.
5. Stir the mixture in the beaker, then carefully pour it into the funnel.
6. Observe what happened.

Observation and Discussion: What you saw happen and why do you think it happened?

When you add the liquids together they start making a bright blue coloured liquid. When you start to filter the liquid through the filter paper there are blue solids on the top and clear liquid coming from the bottom, the reason is that the blue cannot fit through the filter paper because it has large particles in it but the clear liquid has small particles which fit through the filter paper.