grade 7 science pure substances and mixtures ms. willis

Separating SolutionsGrade 7 Science

Pure Substances and MixturesMs. Willis

Learning Goals / Success CriteriaI can describe the processes used to separate

solutions into their components and identify some industry applications of these processes.

Vocabulary: evaporate, evaporation, distillation

Particles of SolutionsRecall that solutions are mixtures in which the particles of the different components are so completely mixed that the mixture appears to be a single substance.

E.g.: Salt water in the ocean…..

How can we separate Solutions?

1. Evaporation

2. Distillation

EvaporationDefinition: the process by which a sample

of matter changes from a liquid to a gas. The solid (or a more concentrated solution) is left behind.

Evaporation is often used to remove the liquid from a solution made of a liquid and a solid.

EvaporationMaple syrup is made by

boiling the sap which evaporates the water and leaves the concentrated solution (syrup) or sugar behind.

Releasing water vapor into the air is not harmful, however, burning fossil fuels to make the heat can be polluting.

DistillationDefinition: the process of separating liquids

in a solution by heating the solution, trapping and cooling the gas, and collecting the resulting pure liquid.

Short video to illustrate:https://

www.youtube.com/watch?v=xxNfJLMNS4E

If you had a liquid solution with more than two liquid components, you could repeat the distillation process to separate all the liquid parts of the solution and use a different collecting flask for each component.

Distillation

DistillationPicture of a seawater distillation plant:

(Seawater must go through several stages to become drinking water.)

Distillation

New technologies are going beyond simple distillation for “desalinating” water:

A closer look at desalinating seawater:https://

www.youtube.com/watch?v=aysj7696b0A