Tetraaminecopper(II) sulphate monohydrate is an inorganic complex compound with the formula [Cu(NH3)4]SO4.H2O. In this experiment,tetraaminecopper(II) sulphate monohydrate is prepared from a reaction of CuSO4.5H2O and NH3 in aqueous solution.
[Cu(H2O)4]SO4.H2O(aq) + 4 NH3(aq) → [Cu(NH3)4]SO4.H2O(aq) + 4H2O(l)
This is a single replacement reaction in which NH3 molecules replace the water molecules originally bonded to the copper(II) ion.
Aim of the Experiment
To synthesize tetraaminecopper(II) sulphate monohydrate and determine the percent yield.
Apparatus and Reagents Needed
- Copper(II)sulphate pentahydrate, CuSO4.5H2O.
- Concentrated Ammonia
- Distilled Water
- Test Tube
- Fume Cupboard
- Filter Papers
- Crushed Ice
- Vacuum Filtration Setup
- Sample Bottle
- Stirring Rod
- Weighing Balance
- Hot Water Bath
- Graduated Pipette
- Weigh about 1.5g of copper(II)sulphate into the test tube and add 4 cm3 of distilled water using a graduated pipette and place the test tube into the hot water bath. Stir gently to dissolve the solid. Remove the test tube of copper(II)sulphate solution from the hot water bath.
N.B: Do the next step in the fume cupboard while wearing gloves.
- Add while stirring, 2 cm3 of conc ammonia solution to the copper(II)sulphate solution.
- Pour 6 cm3 of ethanol into a beaker and transfer the contents of the test tube into the beaker of ethanol, mix then cool the mixture actual yield using the crushed ice.
- Filter the crystals by vacuum filtration. Wash out the test tube with cold ethanol and add to the Buchner funnel. Finally, rinse the crystals with cold ethanol. Dry the solid by leaving the aspirator on to pull air through the funnel. Test for dryness by turning over the solid using a spatula. The dry solid should powder easily and not be clumpy.
- Weigh a sample bottle and record its mass. Carefully transfer your crystals to the sample bottle. Re-weigh and record its mass.
Results and Calculations
- Calculate the relative formula masses of CuSO4.5H2O and [Cu(NH3)4]SO4.H2O.
- Calculate the number of moles of CuSO4.5H2O used in the experiment. Calculate the theoretical yield in grams of [Cu(NH3)4]SO4.H2O.
- Use the recorded masses to derive the actual yield of the product.
- Use the theoretical yield and actual yield to calculate the percent yield.
- Wikipedia (2018), “Tetraamminecopper(II)sulfate”. Retrieved from http://en.m.wikipedia.org/wiki/Tetraamminecopper(II)_sulphate (accessed 28 January 2018).
- Philip, J.S. (1993), “Preparing Tetraamminecopper(II)sulfate Monohydrate: Modular Laboratory Program in Chemistry Series”. Chemical Education Resources, Inc.
- Nigel, S. (2003) “The Preparation of tetraamminecopper(II)sulfate-1-water”, retrieved from www.creative-chemistry.org.uk/alevel/practical.htm (accessed 28 January 2018).
Credits: Nurudeen Yusuf (B.Sc.). Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.