Separating and Mixing

Making a Copper Sulfate Salt

Aim: To produce copper sulfate salt by reacting copper oxide with an acid

Equipment: 
Copper oxide powder, dilute sulfuric acid, measuring cylinder, 2x 100mL beakers, bunsen burner, tripod, gauze mat, funnel, filter paper, themometer, spatula, evaporating basin, stirring rod.

Method:

1. Add 20mL of sulfuric acid to a 100mL beaker. Heat to 70degrees. Turn off your bunsen.
2. Once heated, use a spatula to add pea sized portions of copper oxide. Stir for 30secs
3. Repeat step 2 until no more dissolved.
4. Fold filter paper and place in funnel. Place the funnel in the second beaker.
5. Make sure your first beaker is cool enough to hold and then pour it into the funnel. Gently swirl and allow to filter through.
6. Rinse the beaker and fill with 50mL of water and place on tripod. 
7. Place evaporating basin on top of beaker and pour some solution in.
8. Gently heat until the solution has reduced by half.
9. Take off heat and allow to cool.

Results and Discussion:
The acid quickly reached the required temperature of 70 degrees and it then took multiple portions of the copper sulfate before the solute was no longer dissolving and a very dark blue solution was present. After filtering the solution it became a light blue.
We then placed that solution in an evaporating basin 

After reducing it by half we left it overnight.
The next day there were little blue crystals formed in the basin and no more solvent.

Conclusion:
This experiment involved dissolving a solute in a solvent to create a solution. We then filtered the solution and evaporated it until we were left with the solid again, in the form of crystals- a successful experiment!

Solubility Experiment

Aim:

To investigate the solubility of baking soda, table salt and copper oxide to see which is the most soluble

Equipment:

100mL beaker, 100mL measuring cylinder, salt, baking soda, copper oxide, stirring rod, spatula.

Method:

1. Fill beaker with water
2. Add a spatula full of baking soda.
3. Stir the solution until it dissolves.
4. Repeat step 2 and 3 until no more will dissolve.
5. Record how many spatula fulls were added.
6. Repeat the experiment with salt and copper oxide.

Results:

Baking Soda took roughly 6 spatula fulls before no more would dissolve in 50mL of water.
Salt needed around 9 spatula fulls before no more would dissolve in 50mL of water.

The copper oxide would not dissolve in the water.

Discussion:
The salt was more soluble than the baking soda as when we dissolved the solute in the solvent we were able to dissolve more salt than the baking soda. The solution went clear after stirring each spatula full until no more would dissolve. The copper oxide turned the solution black and would not dissolve, hence the copper oxide is insoluble in water.

Conclusion:
This experiment showed that some solutes are more soluble than others in a solvent such as water. This also showed that some solutes are insoluble, meaning they do not dissolve.

Dilution Experiment

Aim:

To make a dilution series to investigate concentration.

Equipment:

Potassium permanganate crystals, 6 test tubes, test tube rack, tweezers, pipette, 10mL measuring cylinder

Method:

1. Place the test tubes in the rack.
2. Using the measuring cylinder, fill test tube 1 with 10mL of water and fill the remaining test tubes with 5mL of water.
3. Add a single crystal of potassium permanganate to test tube 1.
4. Gently shake until the crystal has dissolved.
5. Using the pipette, transfer 5mL from test tube 1 to tst tube 2.
6. Rinse the pipette thoroughly and continue to transfer from 2 to 3 and so on.

Results and Discussion:

When i added the crystal to test tube 1 the solvent quickly turned purple as the solute dissolved. As i transferred 5mL from one test tube to another the solution got a lighter and lighter shade of purple.

Conclusion:
As i transferred 5mL from one test tube to another i was halving the concentration of the solution as the ratio of potassium permanganate to water in solution became less and less. This is called a dilution series as we slowly diluted the original solution.

Chromatography

Aim: 

To separate the different pigments in inks using paper chromatography.

Equipment:

Ink pens, small beaker, strip of filter paper, ice-block stick, tape, chromatography solution.

Method:

1. Cut a piece of filter paper long enough to reach the bottom of your test tube.
2. Rule a line in pencil 2cm from bottom of paper.
3. Fill test tube with 1cm of chromatography solution (water).
4. Place a dot of ink above the ruled line.
5. Fold over test tube and place in solution.
6. Wait and observe.
7. Repeat with 2 other colours.

Results and Discussion:

The dot of ink ran up the filter paper and as the different pigments separated out. A couple of good examples were using the blue and purple pen because it clearly showed the colours of green/yellow and red/ blue. The one on the right was in fact a black felt tip marker and it clearly showed the separation of many different colours. 

Conclusion:
Some colours are more soluble in water than others as they travelled further up the filter paper. Chromatography also identifies the pigments which a certain colour is made up of.