Separating Mixtures Flashcards Preview

Yr 8 Science end of year exam > Separating Mixtures > Flashcards

Flashcards in Separating Mixtures Deck (12):

An explanation of mixtures

Two or more elements are combined in a way that involves no chemical reactions.
A mixture can usually be separated back into it's original components.


Why we may wish to separate mixtures

We may wish to separate mixtures such as seawater to get the salt from it and the pure water.


The difference between solution and solubility

A solution is a mixture of a liquid and a solid or gas. Solubility is the mass of solute that dissolves in 100g of water.


A brief description of each separation technique.

Filtration separates a liquid from an insoluble solid.
Evaporation is when you evaporate the liquid and leave the solid .
Distillation is a process that uses evaporation and condensation to obtain a solvent from a solution.


Examples for each separation technique

Sand and water
Sea water
Crude oil


An explanation of how each technique works

you can separate sand from water by pouring the mixture into filter paper. Water passes through the filter paper. Sand does not.
You heat the sea water up above a hundred degrees. This causes the water to evaporate, but the salt won't, leaving the salt at the bottom.
Water in the solution boils, steam leaves the solution, steam travels through the condenser and cools down, the steam condenses to form liquid water, Liquid water drips into the beaker.


Which separation technique you use to separate sand from a mixture of sand and water.



Which separation technique would you use to separate salt from a solution of salt in water.



What separation technique would you use to separate a petrol from a mixture of crude oil.



How do you separate inky water from water using distillation

To separate pure water from inky water using this apparatus you need to put the inky water into the round-bottomed flask. You need to then heat the water up to 100 degrees so the water evaporates. We do this as the ink has a higher boiling point than water. The water vapour then travels along the pipe. When it enters the condenser it cools are condenses back into water. It does this as in the condenser cold water flows around the edges cooling the pipe. The pure water then flows into the beaker and the ink is still in the round-bottomed flask.


What is chromatography?

Chromatography is when you put ink on paper and put the paper into the water. The paper then absorbs the water and the ink then travels up the paper, separating the different colour inks.


How can you use chromatography to figure out which pen was used for a forged signature.

You can do the method with different inks and if the same pattern emerges then you know the same pen was used.