Investigate the preparation of soluble salts – Preparation of Copper sulfate) C3 Flashcards
Equation for reaction of copper carbonate and sulfuric acid
CuCO3(s) + H2SO4(aq) → CuSO4(aq) + H2O(l) + CO2(g)
Safety? (4)
- Be careful when using sulfuric acid as it is an irritant (skin, eyes)
- wear safety goggles
- Copper carbonate is harmful if inhaled.
- Very toxic to aquatic life with long‐lasting effects.
Method (7)
- Measure 25cm3 of dilute sulfuric acid and place in a beaker.
- Warm the dilute sulfuric acid for a short time. Do NOT allow the acid to boil.
- Add copper carbonate to the sulfuric acid and stir. Continue adding copper carbonate until there is no further reaction and unreacted copper (II) carbonate is present - it is in excess
4. Allow to cool - then filter the mixture and collect the filtrate solution in an evaporating basin.
5. Heat the filtrate solution in the evaporating basin on a tripod and gauze until the volume is
about one half of what it was originally - to make it more concentrated.
6. Allow the basin to cool and the crystals will form.
7. When the crystals have formed, filter if necessary, dry (between two pieces of filter paper or use a dessicator or in a low temperature oven).
What piece of apparatus would you use to measure 25cm3 of sulfuric acid?
Pipette with pi-pump attached.
Explain why the copper carbonate is added until it is in excess.
To ensure all the acid was reacted.
State one way in which you would know that the copper carbonate is in excess.
Solid lies at the bottom of the beaker/conical flask OR No more fizzing/gas given off.
Why is the solution not evaporated to dryness?
If evaporated to dryness then water of crystallisation would be driven off out of the crystals.
Why do crystals form as the solution is cooled?
As solution is cooled solubility decreases and crystals will form.
State two methods of drying the crystals
Low temperature oven
Dry between 2 pieces of filter paper
