Lesson 15

Separating a Soluble and an Insoluble Substance

Write the definitions for the following terms:

a. Properties of solutions:

b. Solubility:

c. Phase change:

Two separation techniques are related to solubility are filtration and evaporation.

Evaporation:

- Solutes are present in solutions, and their mass is conserved.

- Evaporation can be used to recover solids from solutions.

Filtration:

- both solutes and solvents can pass through filter paper.

- Example: rock salt, or halite , occurs naturally, usually in underground beds created from ancient surface deposits that formed when enclosed saline waters evaporated. The resulting salt beds are often distorted by tectonic forces, which cause them to form into domelike subterranean structures called salt domes. Salt ex extracted by salt domes either directly, by “room-and-pillar” mining, or by making a solution from the deposit and water. In the United States, salt is usually extracted using the room-and-pillar method, in which rock salt is blasted, removed by machine, crushed, and taken to the surface, where it is screened and packed. In making a solution, hot water is forced into the deposit and returns to the surface as a saturated solution of brine. The water is then evaporated to obtain the salt.

Design an inquiry (scientific method) to obtain a clean sample of salt from crushed sodium nitrate, Na NO3 (rock salt).

Hint: Materials:

Filters sodium nitrate

Funnels graduated cylinders

Scoops spoons

Beakers pipettes

Lap scoops cups

Water loupes