An investigative approach into some factors effecting intact crystal growth of Copper (II) sulfate pentahydrate (CuSO4 • 5H2O) under room conditions and searching of suitable medium circumstances and alternative method favoring this type of growth.

摘要

In most laboratories, crystal growth of soluble salts in water is made with classical methods: obtaining a supersaturated or saturated solution at a higher temperature, slowly cooling or evaporating the solution. A chosen crystal nucleus is then used as a “seed crystal”, and the largest crystal formed is re-put into a saturated solution of itself while filtering other precipitates being formed. However, this methodical approach needs intensive and continuous care on crystal, consumes both time and solute. This study is therefore aimed to find such stable circumstances that will supply intact crystal growth of an ionic crystal under room conditions grown by this method, with an alternative method not requiring the prerequisite of periodical care. ududThe researches stated that one-piece crystal growth required a reversible, kinetically limited reaction pathway. Second task was to find an easily obtainable and soluble salt used commonly and could easily form intact crystals, resistant to possible random changes in the determined constants during time that may erroneously happen during experimentation in a school laboratory. It was copper (II) sulfate pentahydrate. ududA series of experiments are then conducted including attempts to change the vapor pressure and phase of the solution, changing the supersaturation temperature, cooling rate, cleanliness and the evaporation rate of the system in basis of a controlled experiment. The experimentation lead itself to the conclusion that: ududCombination of decreased vapor pressure in a constant room temperature; clean system in the most soluble phase let through continuous evaporation can produce intact crystals of Copper (II) sulfate with an alternative method that is requiring only initial care.ududAlthough the experimentation was successful, I was unable to find a quantitative optimum of the mentioned variables due to the time constraint. At least, I think I prepared a basis of alternative approach on a simple growth method. ud