ks3 chemistry l.
Download
Skip this Video
Download Presentation
KS3 Chemistry

Loading in 2 Seconds...

play fullscreen
1 / 32

KS3 Chemistry - PowerPoint PPT Presentation


  • 195 Views
  • Uploaded on

KS3 Chemistry. 7H Solutions. Contents. 7H Solutions. Introducing solutions. Separating mixtures. Chromatography. More about solubility. Summary activities. Mixtures and solutions. A mixture is two or more substances that are mixed together but not chemically joined.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'KS3 Chemistry' - chiku


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
ks3 chemistry

KS3 Chemistry

7H Solutions

contents
Contents

7H Solutions

Introducing solutions

Separating mixtures

Chromatography

More about solubility

Summary activities

mixtures and solutions
Mixtures and solutions

A mixture is two or more substances that are mixed together but not chemically joined.

A solution is a special type of mixture that is made when

a solid dissolves and mixes a liquid.

For example, a cup of instant coffee is a solution.

The solid that dissolves (e.g. coffee granules) is called the solute.

The liquid that does the dissolving (e.g. hot water) is called the solvent.

How many other examples of solutions can you think of?

contents6
Contents

7H Solutions

Introducing solutions

Separating mixtures

Chromatography

More about solubility

Summary activities

salty water
Salty water

Where does the salt around the Dead Sea come from?

separating mixtures
Separating mixtures

Sea water is a salty mixture that contains water, salt,

sand and other substances.

The Dead Sea is a salty lake that contains some of the saltiest water in the world!

The Dead Sea is almost six times more salty than the ocean, so nothing is able to live in it and that’s why it is called “dead”.

The substances in a mixture, such as salty water, are not chemically joined which means they can be separated.

How is salt separated from salty water?

how are solids separated out of mixtures
How are solids separated out of mixtures?

Separating an insoluble solid and a liquid

If a solid is insoluble (e.g. sand in water) then

it is easy to separate it by filtering the mixture.

The insoluble solid cannot pass through the filter paper but the water can.

Separating a soluble solid and a liquid

To separate a soluble solid from a liquid

(e.g. salt and water), evaporation can be used.

The solution is heated so that the water evaporates and leaves the dissolved solid behind.

separating salt from sea water
Separating salt from sea water

The main salt dissolved in sea water is “common salt”.

In hot areas, how can the Sun be used to separate the salt from sea water?

The heat of the Sun evaporates the water, the salt is left behind and collected in salt beds.

Salt can also be obtained from ‘rock salt’ found in layers under the ground.

How are dissolving, filtering and evaporating used to separate

the salt from rock salt?

separating solvents
Separating solvents

Evaporation can be use to separate and collect the solute in a solution. How can the solvent be collected?

The technique use to obtain a solvent from its solution is

called distillation.

Distillation has three steps:

  • evaporating;
  • condensing;
  • collecting.

The solution is heatedsothatthesolvent(a liquid)evaporates and is turned into a gas. The solute is left behind.

The gas cools in the condenser and turns back into a liquid.

This liquid is collected and is pure solvent.

contents16
Contents

7H Solutions

Introducing solutions

Separating mixtures

Chromatography

More about solubility

Summary activities

what is chromatography
What is chromatography?

Method A

Method B

pipette

solvent

spot of mixture

spot of mixture

solvent

Chromatography is used to separate mixtures of coloured or non-coloured substances that are soluble in the same solvent.

A spot of the mixture is placed on some filter paper.

In method A, the solvent is soaked up the paper.

In method B, the solvent or is slowly dripped onto the paper.

The substances in the mixture get separated because more soluble substances spread along the paper faster.

identifying dyes in a mixture
Identifying dyes in a mixture

1 2 3 4 5 6

1 2 3 4 5 6

mixture

mixture

Chromatography can be used to find out if a dye is made up of a single coloured substance or a mixture.

The mixture consists of dyes

3 and 5.

Dots of known single dyes are placed alongside the dot for the unknown mixture.

After the solvent washes through the paper, the pattern of the dyes in the mixture is compared with the single dyes.

Which dyes does the mixture consist of?

identifying dyes in a mixture20
Identifying dyes in a mixture

Which dyes are in the mixture?

  • 2 3 4 5 6
  • 2 3 4 5 6

mixture

mixture

The mixture consists of dyes 1 and 4.

contents21
Contents

7H Solutions

Introducing solutions

Separating mixtures

Chromatography

More about solubility

Summary activities

conservation of mass
Conservation of mass

If 10g of salt is added to 50g of water, what is the mass of the solution?

10g

50g

60g

?

How much salt will be recovered if the mixture is separated by evaporation?

conservation of mass extension
Conservation of mass – extension

If 10g of salt is added to 50g of sea water, what is the mass of the solution?

10g

50g

60g

?

How much salt will be recovered if the mixture is separated by evaporation?

how does temperature affect solubility
How does temperature affect solubility?

Does sugar dissolve in a cup of cold tea?

The sugar does dissolve but not as much as in a cup of hot tea.

The sugar is more soluble at higher temperatures.

The amount of a solute that can dissolve at a given temperature is called its solubility.

How does the solubility of a substance change with temperature?

The solubility of a substance usually increases as the temperature increases.

contents27
Contents

7H Solutions

Introducing solutions

Separating mixtures

Chromatography

More about solubility

Summary activities

glossary
Glossary
  • dissolving –The mixing of a solid with a liquid to make a

solution.

  • mixture –Two or more substances that are mixed together

but are not chemically joined.

  • saturated –A solution containing the maximum amount of
  • solute that it can hold.
  • soluble – A substance that can dissolve in a solvent.
  • solubility –A measure of how much solute can dissolve in

a solvent at a given temperature.

  • solute –Solid that dissolves in a solvent to make a solution.
  • solution –Mixturemadewhenasolutedissolvesinasolvent.
  • solvent –Liquidinwhichasoliddissolvestomakeasolution.
ad