How to grow 3 crystals from 1 substance (Easy experiment)
22.7 هزار بار بازدید -
6 سال پیش
-
A similar experiment is included
A similar experiment is included in the MEL Chemistry subscription
For cool and safe experiments to do at home sign up to MEL Science here: http://bit.ly/2H7XNfA
Safety precautions
Wear protective gloves and glasses.
Reagents and equipment:
* potassium hexacyanoferrate(III) (480 g);
* hot water (800 ml);
* cup;
* fishing line;
* stick;
* funnel;
* foil;
* cotton wool.
Step-by-step instructions
Sprinkle potassium hexacyanoferrate(III) into the cup and pour hot water over it. Stir thoroughly for 10–15 minutes. We get a saturated solution. Separate the solution from the remaining crystals and dust using a funnel with cotton wool. Cover the solution with foil and leave in a dark place. 24 hours later, pour the solution into another cup. Place the crystals that have formed in a sealed container, so they do not disintegrate. Lower seeds for crystals into the saturated solution of potassium hexacyanoferrate (III):
1) attach cotton wool to the fishing line, soak it in the saturated solution of potassium hexacyanoferrate(III) and dry;
2) from the crystals obtained earlier, select the crystal with the most regular shape and attach it to the fishing line;
3) simply let the third seed–the small crystal–sink to the bottom.
Cover the cups containing the seeds with foil and put in a dark place. A month later, crystals of different shapes will grow from the seeds – a “hedgehog”, a monocrystal and a druse!
Unlike precious stones, crystals of potassium hexacyanoferrate(III) are soluble in water. So if you don’t like the shape of the crystal, the experiment can easily be repeated.
Processes description
In a saturated solution, a substance is at maximum concentration and does not dissolve further at the given temperature. At room temperature (25 °С, 77 °F), the solubility of potassium hexacyanoferrate(III) in water is around 50 g/100g of water. When heated to 90 °С (194 °F), solubility increases to 92–100 g of water. When the hot solution cools down, it becomes oversaturated, i.e. more of the substance is dissolved in it at the given temperature. As a result, the “surplus substance”–in our case potassium hexacyanoferrate(III)–precipitates in the form of crystals, and the solution becomes saturated once more. This is how the seeds for the crystals were formed.
A saturated solution from which water evaporates becomes oversaturated. As a result, the surplus of salt precipitates, and the crystals grow from it. If seeds are placed in this solution, for example, a crystal or cotton wool with crystals, they do not dissolve, but will become covered in ions of the dissolved salt, thus forming crystals of a large size.
For cool and safe experiments to do at home sign up to MEL Science here: http://bit.ly/2H7XNfA
Safety precautions
Wear protective gloves and glasses.
Reagents and equipment:
* potassium hexacyanoferrate(III) (480 g);
* hot water (800 ml);
* cup;
* fishing line;
* stick;
* funnel;
* foil;
* cotton wool.
Step-by-step instructions
Sprinkle potassium hexacyanoferrate(III) into the cup and pour hot water over it. Stir thoroughly for 10–15 minutes. We get a saturated solution. Separate the solution from the remaining crystals and dust using a funnel with cotton wool. Cover the solution with foil and leave in a dark place. 24 hours later, pour the solution into another cup. Place the crystals that have formed in a sealed container, so they do not disintegrate. Lower seeds for crystals into the saturated solution of potassium hexacyanoferrate (III):
1) attach cotton wool to the fishing line, soak it in the saturated solution of potassium hexacyanoferrate(III) and dry;
2) from the crystals obtained earlier, select the crystal with the most regular shape and attach it to the fishing line;
3) simply let the third seed–the small crystal–sink to the bottom.
Cover the cups containing the seeds with foil and put in a dark place. A month later, crystals of different shapes will grow from the seeds – a “hedgehog”, a monocrystal and a druse!
Unlike precious stones, crystals of potassium hexacyanoferrate(III) are soluble in water. So if you don’t like the shape of the crystal, the experiment can easily be repeated.
Processes description
In a saturated solution, a substance is at maximum concentration and does not dissolve further at the given temperature. At room temperature (25 °С, 77 °F), the solubility of potassium hexacyanoferrate(III) in water is around 50 g/100g of water. When heated to 90 °С (194 °F), solubility increases to 92–100 g of water. When the hot solution cools down, it becomes oversaturated, i.e. more of the substance is dissolved in it at the given temperature. As a result, the “surplus substance”–in our case potassium hexacyanoferrate(III)–precipitates in the form of crystals, and the solution becomes saturated once more. This is how the seeds for the crystals were formed.
A saturated solution from which water evaporates becomes oversaturated. As a result, the surplus of salt precipitates, and the crystals grow from it. If seeds are placed in this solution, for example, a crystal or cotton wool with crystals, they do not dissolve, but will become covered in ions of the dissolved salt, thus forming crystals of a large size.
6 سال پیش
در تاریخ 1397/03/10 منتشر شده
است.
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