Chemistry Solvents & Separation Techinques

Question 1

Soluble and insoluble

Answer 1

If a solid dissolves into a liquid it is soluble the solid seems to disappear, If a solid does not dissolve in a liquid it is insoluble and the solid will be visible floating in the liquid.

Question 2

Solvents and solutes

Answer 2

The substance that dissolves is the solute, the liquid that the solute dissolves in is the solvent a solution is formed

Question 3

Different solvents

Answer 3

Water is an important solvent because it dissolves many solutes it is safe, cheap, and widely available.
Water can be made a better solvent by adding a detergent.
Substances that are insoluble in water maybe soluble in other solvents

Question 4

Saturated solutions

Answer 4

A dilute solution contains a small amount of solute dissolved in a large volume of solvent
A concentrated solution contains a large amount of solute dissolved in a small volume of solvent
If a solution Is saturated, it means the solvent cannot dissolve any more at that temperature.

Question 5

Getting more to dissolve

Answer 5

The saturation point of a solution depends on the temperature of the solvent
If the saturated solution is heated, more solute can be dissolved until a new saturation point is reached

Question 6

Growing crystals

Answer 6

Crystals can be produced in a lab by making a saturated solution and allowing it to cool.
Cooling a saturated solution quickly would produce small crystals.
Cooling a saturated solution slowly would produce large crystals

Question 7

Types of crystals

Answer 7

Different substances produce crystals if different shapes
All crytsals have smooth faces and sharp edges

Question 8

Melting and Dissolving

Answer 8

When a solid is heated above its melting point it melts to form a hot liquid
When a substance dissolves

Question 9

Pure substances

Answer 9

A pure substance is a single substance which is not mixed, with anything else. It is one single chemical

Question 10

Mixtures

Answer 10

A mixture contains 2 or more different substances mixed up together

Question 11

Separating mixtures

Answer 11

A mixture can be separated into pure substances
This is because the atoms are not chemically joined

Question 12

Filtration

Answer 12

Liquid and insoluble solid
Filter paper
Filter funnel
Filtered solid residue
Filtered liquid filtrate

Question 13

Evaporation

Answer 13

Solvent vapour
Evaporating basin
Solution
Gauze
Heat⬆️

Question 14

Evaporation

Answer 14

The solid salt dissolved when it added to the water a solution was formed.
Filtration could not be used to serparate the salt and water because no solid particles were present
The solid salt was left in the evaporating basin once the water had evaporated

Question 15

Separation experiment

Answer 15

Separating a mixture of salt and sand the mixture was successfully separated using filtration followed evaporation

Question 16

Chromatography

Answer 16

Chromatography can be used to separate small amounts of soluble substances
As the solvent travels up the chromatography paper the soluble particles are dragged up with it

Question 17

Chromatography

Answer 17

Comparing the distance travelled by the spots from the mixture to known (or reference) substances allows for identification of the components of the mixture

Question 18

Miscible and Immiscible

Answer 18

If 2 liquids mix they are said to be miscible
If 2 liquids do not mix they are said to be immiscible and 2 distinct layers are formed

Question 19

Separating funnel

Answer 19

Liquids will be immiscible if they have different densities
A serparating funnel can be used to serparate immiscible liquids
The more heavier liquid will form the bottom layer and be run off first

Question 20

Distillation

Answer 20

Distillation is a technique used to serparate a mixture of miscible liquids
In order to achieve serparation the 2 liquids must have different boiling points
The condenser cools the gas and turns it into a liquid for collection