Separating Techniques Flashcards

1
Q

What is a solute

A

The substance which dissolves in a solution

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2
Q

What is the solution

A

The name for a mixture of a solute and solvent

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3
Q

What is a solvent

A

A liquid which dissolves a solute

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4
Q

How would you design an experiment to see how much salt can dissolve in water, (6)

A

Measure out your given volume of water using a measuring cylinder and pour it into a beaker.

Take your given amount of salt and weigh it

Add salt, one spatula at a time and stir until it dissolves

Stop when your salt no longer dissolves

Reweigh your container of salt to see how much you’ve used.

Each group uses a different volume of water and class results are collected.

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5
Q

What does “saturated” mean

A

When no more solute can dissolve in a solution

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6
Q

Give the 4 states + symbols

A

(s) = solid
(g) = liquid
(g) = gas
(aq) =aqueous- dissolved in water

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7
Q

What is filtration

A

The purpose of filtration is to separate an isolate solid from a solution.

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8
Q

Describe the process of filtration

A

Solid is left behind on the filter paper. Liquid containing any dissolve solids pass through

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9
Q

How does filtration work

A

The solid particles are too big to pass through holes in the filter paper. (Residue)

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10
Q

Give an example of filtration

A

Sand from salt water

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11
Q

What is the purpose of crystallisation

A

To separate a soluble solid from a solvent

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12
Q

Describe the process of crystallisation

A

Take your solution, heat until crystals start to form. Then leave in a warm place for he rest of the solvent to evaporate.

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13
Q

Give an example of crystallisation

A

Copper sulphate crystals from copper sulphate solution.

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14
Q

Give two mixtures which can be separated from filtration

A

Iron fillings and water

Sand and water

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15
Q

Give 3 mixtures which can be separated with crystallisation

A

Salt and water
Sugar and water
Copper sulphate and water

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16
Q

Describe an experiment in which you can extract salt from rock salt

A

First add 5 spatulas of rock salt into a beaker and then add 20ml of water. Stir this for 3 minuets. Next, make a filter funnel by getting some filter paper and folding it in half twice. Place this in a funnel over an empty beaker. Pour the rock salt mixture into the funnel and wait until all has passed through. The liquid should still be quite blue. Pour this into an evaporating dish and place over a bunsen burner. Wear goggles and keep heating until all the water has evaporated.

17
Q

What is simple dilatation

A

Is used to separate a solvent from a solute can also be used when two miscible liquids have very different boiling points.

18
Q

What is fractional distillation

A

Is used when several miscible liquids are mixed, and have close boiling points. (Crude oil).

19
Q

How would you separate ink mixture and water

A

Heat is supplied to the flask to evaporate the water and produce steam, this steam condenses in the Liebig condenser and runs down the tube to be collected. The powder dye is left behind in the flask

20
Q

Metal oxides are called….

A

Bases

21
Q

Some bases…..in water to form soluble metal hydroxides. Soluble bases are called…..

A

Disslove

Alkalies

22
Q

…..are compounds which have replaceable hydrogen ions.

A

Acids

23
Q

……are compounds which have replaceable hydroxide ions

A

Alkalies

24
Q

Hydrochloric acid gives off salt called…….

A

Chlorides

25
Q

Sulphuric acid gives salt called……

A

Sulphates

26
Q

Nitric acid gives salts called

A

Nitrates

27
Q

Neutralisation is an……chemical reaction

A

Exothermic

28
Q

How would you make copper sulphate crystals.

9

A

Add 20cm3 of sulphuric acid to the 100cm3 beaker.Heat carefully on the tripod on a blue flame until nearly boiling. DO NOT BOIL THE ACID!

When the acid is hot, use a spatula to add a spatula of copper oxide to the beaker. Stir the mixture gently. If it all dissolves then keep adding as there is still acid to be reacted.

Allow the beaker to cool slightly whilst you set up the next stage.

Place the filter funnel in the neck of the clinical flask.

Fold the filter paper into a funnel and put in the funnel.

Gently pour the mixture in to the filter funnel. Allow to filter through.

A clear blue solution should collect in the flask, If the solution is not clear and black solution still remains then repeat the filtration process.

Pour this into an evaporating basin gently heat some of the water until the solution is saturated.

Leave the evaporating basin in a warm place to evaporate more water. Crystals will form.

29
Q

What does chromatography separate

A

A mixture of coloured substances such as dyes.

30
Q

Why is the line drawn in paper in chromatography

A

Because with a pen, the ink would was away and be carried up the paper.

31
Q

How do you calculate the Rf value

A

Distance travelled by solvent

32
Q

How do you operate two immiscible liquids

A

A separating funnel is used. When the tap is open, the bottom layer runs out and can be removed while the top layer remains in the funnel.

33
Q

How would you design an experiment to do fractional distillation.

A

When heating, the mixture evaporates and goes up the column. They then meet the cool glass bead and condense back down. They the meet more hot vapour rising up which makes them evaporate agin and rise further up the column. Eventually the liquid with the lowest boiling point reaches the top and distils over.