Separation Techniques Solutions

Why would we want to separate mixtures? to purify water so that it is safe to drink to extract a mineral from rocks to be able to use (example, quartz or gold) to eliminate the pulp in freshly squeezed juice to make soup broth

What we have to think of when we separate mixtures… We need to look for a difference between the parts of the mixture and then use a separation method that takes advantage of this difference. These are some of the properties that can be used:   The size of the particles The density of a substance The boiling point of a substance The solubility of a substance

Ways to Separate Mixtures There are several ways of separating mixtures. The ones we will be focusing on are: Sedimentation & Decantation Filtration Distillation Magnetism

Sedimentation and decantation AKA : settling out and pouring out When it works: The size of the particles of a substance have to be large enough to settle to the bottom of the container.   The larger the size of the particles the faster they will settle to the bottom of the container. The liquid above the sedimented particles should be quite clear and can be poured off easily. This method only works for heterogeneous mixtures! When it doesn’t work: As the size of the particles get smaller , it may take too long for them to settle to the bottom of the container and the particles may also be easily stirred up if we try to pour off the liquid above the particles .

Sedimentation Decantation

Examples: noodles or vegetables in a soup settle to the bottom muddy water (mud settles to the bottom) orange juice that has pulp salad dressing made of oil and vinegar

Filtration Downfall: When it works: Vocabulary:   The size of the particles of a substance have to be too large to pass through the holes of a filter . This method only works for heterogeneous mixtures! Downfall: Filtration takes time and may take longer as the residue accumulates on the filter. Vocabulary: Residue: is what is left on the filter Filtrate: is the liquid that passes though the filter

Mixture of solid and liquid Stirring rod Filtrate (liquid component of the mixture) Filter paper traps solid Funnel

Distillation When it works: When it Doesn’t work Vocabulary The substance in the mixture with the lowest boiling point will evaporate first and will then condense in another cooled container. This method is the only one that works for SOLUTIONS! (homogeneous mixture) When it Doesn’t work -This method cannot be used if 2 substances have the same boiling point Vocabulary Distillate: is the liquid that evaporates Residue: is the substance left behind in the original container  

. Separates homogeneous mixture on the basis of differences in boiling point

Examples: separating salt from saltwater making distilled water in the lab commercially distilling alcohol (ethanol used for thermometers)

MAGNETISM When it works: -Can separate metal particles when they are magnetic (contain nickel, cobalt, iron, etc)