LAB: Separation Methods #1 – Purification of Copper sulfate
- Copper (II) sulfate pentahydrate is a blue powder (or crystal) – it is soluble in water.
- Copper (II) carbonate is a green compound insoluble in water. (The Statue of Liberty is covered in copper carbonate)
- Dissolving the copper (II) sulfate will allow the mixture to be separated by filtration. We could retrieve the carbonate. In this case we will test the carbonate using sulfuric acid.(Part B)
Purpose of the lab:
Separate the copper carbonate (impurity) present in the copper sulfate sample.
- 2- 150 cm3 beaker (they may be bigger)
- filter funnel
- filter paper
- glass rod
- hot plate
- Ceramic pad (heat proof mat)
- Ring stand
- Ring to support the funnel
- safety glasses
- weighing boat with mixture sample
- distilled water
Procedure: Part 1 – separating the mixture
- Put around 75 mL of distilled water in one beaker.
- Using the spatula, transfer the mixture from the weighing boat to the beaker containing the water.
- Stir for 10 seconds using the glass rod.
- Place the beaker on the hot plate
- Heat gently, while stirring the mixture with the glass rod.
- When the water is about to boil, turn off the hot plate
- Continue stirring for 1 minute.
- When the liquid stops bubbling, transfer the beaker from the gauze to the ceramic pad. DO NOT USE YOUR BARE HANDS. USE A BEAKER TONG.
- Leave the beaker to cool and settle for 2 minutes. Do not stir again.
- Filter the mixture using the beaker tong and the glass rod to guide the liquid into the funnel.
- Heat up the filtrate (liquid) obtained until you get around half the volume.
- Label the beaker and leave it in a place to finish the evaporation process. The less the liquid moves, the better and bigger crystals will be obtained.
Procedure: Part II – Testing the solid for the presence of carbonates
Carbonates react with acids releasing CO2 and H2O
We will test the presence of copper carbonate in the residue of the filtration.
CuCO3(s) + H2SO4(aq) => CuSO4(aq) + H2O(l) + CO2(g)
green =====> blue
- We will react part of the residue in the beaker and in the filter paper.
- Add some diluted sulfuric acid.
- Write your observations.
- Write the properties of the impure substance: state of the matter, color, smell if any, etc.
- What happened when you try to dissolve the compound in distilled water? What color was the solution. Was it clear or cloudy?
- What did you observe when you turned off the Bunsen burner?
- what color was the liquid? what color was the solid at the bottom?
- what was the color of the filtrate?
- what color was the residue?
- After heating the second time, the solution gets darker or lighter? Write down your explanation about it
- what happened when we put the solid to react with sulphuric acid?
- write the formula of the reaction
- is the compound obtained the same that we have in our solution? how can you tell?
ITEMS TO BE INCLUDED IN THE LAB
- PROCEDURES (INCLUDING #2)
- LAB SETUP
- Must be a “snapshot” of the arrangement of the lab equipment, not a “collection” of lab items.
- must be drawn in pencil and color pencils
- must be labelled
- OBSERVATIONS -ANSWERS IN COMPLETE SENTENCES
** FOLLOW THE INSTRUCTIONS BELOW.
** COMPLETE THE LAB REPORT USING PEN FOR ALL WITH THE EXCEPTION OF GRAPHS AND LAB SETUP.
** USE COLORS SHOWING THE DIFFERENT COMPOUNDS SEEN OR OBTAINED.