Copper sulfate is an inorganic compound commonly found in pesticides to kill bacteria, algae, plants, snails and fungi. It is the result of the combination of sulfuric acid and cupric oxide; it is also used to develop bright blue crystals as a fun science experiment.
Steps
Part 1 of 3: Prepare the Copper Sulfate Solution
Step 1. Gather the materials
Arrange the objects in one area; by having everything you need in one place, you can avoid having to stop in the middle of the experiment to find what you need. You need:
- Cupric oxide;
- Sulfuric acid;
- Goggles;
- Glass beaker;
- Conical flask;
- Spatula;
- Glass stick for mixing;
- Evaporating dish;
- Bunsen burner;
- Tripod;
- Paper filter;
- Funnel filter.
Step 2. Prepare the work area
Put the beaker on the tripod under which you place the Bunsen burner; don't forget to wear eye protection.
Step 3. Pour the sulfuric acid into the bowl
Heat it almost to boiling point.
Step 4. Add small pieces of cupric oxide to the solution
Use a putty knife to avoid burning yourself.
Step 5. Stir the mixture lightly with the glass stick
Don't be too vigorous to prevent the hot solution from splashing on the skin; mix for about thirty seconds after each addition of cupric oxide.
Step 6. Continue heating the solution until you have inserted the last piece of copper oxide
You need to make sure that the chemical reaction has taken place, which takes about a couple of minutes; the solution should be cloudy and contain a black powder.
Step 7. Turn off the Bunsen burner
You should use litmus paper to make sure there is no acid residue in the solution; otherwise, fumes are formed after the filtration process.
Step 8. Set the beaker aside
You can let it cool down as you prepare to filter the solution.
Part 2 of 3: Filter the Solution
Step 1. Insert a funnel filter into the opening of a conical flask
Fold the paper filter and insert it into the funnel.
Polyethylene tools are cheaper and safer than glass ones; furthermore, make sure that the funnel is not too large in diameter, otherwise the structure made up of the various elements could become unstable
Step 2. Make sure you can hold the beaker safely
If it is too hot, wait for its temperature to cool down; however, remember that the content is still hot, so handle the container with care.
Step 3. Gently shake the liquid by moving the beaker in a circular fashion
Pour the solution into the funnel filter.
Step 4. Wait for all liquid to pass through the filter
You should notice that the solution in the flask is blue; if it is still quite cloudy due to the presence of black powder, repeat the filtration process until it becomes pure.
Part 3 of 3: Developing the Copper Sulfate Crystals
Step 1. Rinse the beaker
You have to use it to "cultivate" the crystals and you have to prevent the filtered solution from being contaminated by residues.
Step 2. Pour the blue liquid into the bowl
Be careful during this step, as the solution may still be hot and burn you.
Step 3. Store the beaker in a warm place where it will not be disturbed for at least a week
At this stage the water evaporates and crystals should form.
- This evaporative crystallization method could take weeks, depending on the temperature where you placed the container; eventually well formed crystals develop.
- You can also heat the solution on a Bunsen burner until a third or half of the water has evaporated and wait for the mixture to cool; this method of crystallization by cooling produces more irregular crystals.
