science test tuesday

What’s the purpose of filtration?

Separates an insoluble solid from a liquid (or solution)

What’s the key principle for filtration?

Particle size. The solid particles are too large to fit through the tiny holes in the filter paper

What are 2 key words related to filtration?

Residue - the solid left behind on the paper

Filtrate - the liquid that passes through

Example - separating sand from water

What’s the purpose of evaporation?

Separates a soluble solid from a liquid (solution) to obtain the solid

What are the key principles of evaporation?

Boiling points. The solvent (liquid) has a much lower boiling point than the solute (solid), so it evaporates

What method is used for evaporation?

The solution is heated in an evaporating dish until the solvent evaporates, leaving the solid crystals behind

What us the purpose of crystallisation?

Produce pure solid crystals from a solution

What’s the key principle to crystallisation?

Solubility decreases as temperature decreases

What’s the method for crystallisation?

A solution is heated to evaporate most of the solvent, creating a concentrated (“saturated”) solution. As it cools, the solubility decreases, and crystals form

What’s the purpose of simple distillation?

Separates a liquid solvent from a solution, or two miscible liquids with very different boiling points.

Whats the key principle in simple distillation?

Differences in polling points

What is the method used from simple distillation?

Heat - the mixture is heated. The component with the lower boiling point evaporates first

Condense - the Vapor travels through a condenser, where cooled water cools it back into a liquid

Collect - the pure liquid is collected

Whats the purpose of chromatography?

Separates mixtures of Soluble substance, such as dyes in inks or pigments in plants

Whats the key principle in chromatography?

Substances travel at different speeds through a stationary phase (paper) based on their solubility in the mobile phase (solvent)