Дробная кристаллизация смеси соли и песка

Разделение смеси с использованием различий в растворимости

Crystallization Beginner (Middle School) 35 мин ~$3,00

Цель

Разделить смесь соли и песка методом дробной кристаллизации, демонстрируя растворение, фильтрацию и кристаллизацию упариванием.

Предпосылки

This classic separation technique exploits the fact that salt dissolves in water while sand does not. The mixture is dissolved in hot water, filtered to remove sand, and then the salt is recovered by evaporation. This is fundamentally how salt has been harvested from seawater for millennia.

Предупреждения по безопасности

  • Handle hot evaporating dish with tongs
  • Do not heat to dryness too rapidly — spattering risk

Требуемые СИЗ

goggles

Материалы

  • Salt-sand mixture (10 g)
    Pre-mixed approximately 50:50
  • Distilled water (100 mL)

Оборудование

250 mL beaker Filter paper Funnel Evaporating dish Hot plate Stirring rod Analytical balance

Процедура

1

Weigh 10 g of the salt-sand mixture and record the mass.

2 мин
2

Add the mixture to 100 mL of warm water in the beaker. Stir for 5 minutes to dissolve all the salt.

5 мин
3

Filter the mixture through filter paper. The sand remains on the filter; the salt solution passes through.

5 мин
4

Rinse the sand on the filter with a small amount of distilled water. Dry the sand and weigh it.

5 мин
5

Pour the filtrate into the evaporating dish. Heat gently on the hot plate to evaporate the water.

12 мин Remove from heat before completely dry
6

Once dry, weigh the recovered salt. Calculate the percentage of each component.

3 мин
7

Compare the total recovered mass with the initial mass. Calculate percent recovery.

3 мин

Ожидаемые результаты

The total mass of recovered salt + sand should be close to the original 10 g (typically 90-98% recovery). Some loss occurs during transfer and on filter paper. The separated components should be visually distinct.

Уборка

Salt solution can go down the drain. Sand can go in the trash. Rinse all glassware.

Детали

Категория
Crystallization
Сложность
Beginner (Middle School)
Продолжительность
35 мин
Прим. стоимость
$3,00
Шаги
7
Материалы
2

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Выращивание кристаллов квасцов 30 min Выращивание кристаллов сульфата меди 30 min Выращивание радужных кристаллов висмута 45 min Кристаллизация салола (фенилсалицилата) 30 min Перекристаллизация бензойной кислоты 45 min Пересыщение и мгновенная кристаллизация 35 min Сахарные кристаллы (леденцы на палочке) 25 min

Frequently Asked Questions

What is the objective of Дробная кристаллизация смеси соли и песка?
Разделить смесь соли и песка методом дробной кристаллизации, демонстрируя растворение, фильтрацию и кристаллизацию упариванием.
How difficult is Дробная кристаллизация смеси соли и песка?
This experiment is rated as Beginner (Middle School). It takes approximately 35 minutes to complete.
What safety precautions are needed for Дробная кристаллизация смеси соли и песка?
Key safety precautions include: Handle hot evaporating dish with tongs; Do not heat to dryness too rapidly — spattering risk.
What materials are needed for Дробная кристаллизация смеси соли и песка?
The main materials required are: Salt-sand mixture, Distilled water.
What results should I expect from Дробная кристаллизация смеси соли и песка?
The total mass of recovered salt + sand should be close to the original 10 g (typically 90-98% recovery). Some loss occurs during transfer and on filter paper. The separated components should be visually distinct.