MATTER AND ITS

CHARACTERISTICS

MATTER:

It is anything that has a mass and volume.

It is anything that has a mass and occupies a space.

Objects are distinguished

from each other by :

Physical properties Chemical properties

Physical properties:

1- Colour ,taste and smell.

2- Density.3- Melting point.4- Boiling point.5- Hardness.6-Electric conductivity.7- Thermal conductivity.

** the colour ,taste and smell:

To differentiate between gold and iron we used co lour.

To differentiate between salt and sugar we used Taste.

To differentiate between perfume and vinegar we used smell.

DENSITY:

MASS:It is the amount

of matter that the body contains.

measured٭unit :

Kg -gm

VOLUME:It is the space

that a substance occupies.

measured٭unit :

cm3

DENSITY:

It is the mass of unit volume of matter.

OR It is the mass of one cubic

centimeters of matter.

Density=

M

D V

Mass volume

Measuring unit:

gm\cm3

Problems:

Note:

Materials which have higher density than water sink in it .

Ex: iron – metallic- coin . Materials which have lower

density than water float on its surface .

Ex: ice- cork – drops of oil.

Life applications on the density: 1- water is not used to put out

petrol fires. 2- Balloons filled with hydrogen or

helium rise up in air carrying flags during festivals.

3- the determination of the change in the of matter is taken as an evidence of the purity of matter .

3- Melting point:

It is the temperature at which a matter begins to change from a solid state to a liquid state.

Note: different solids have a definite

melting point . some solid have low melting

point such as wax –butter some solids have high melting

point such as iron –copper.

Life applications on melting process:

1- In manufacture of alloys copper-gold to make jewels .Nickel –chrome to make

heating coils.2- In manufacture of

cooking pots From aluminum – stainless

steel which do not rust.

4- Boiling point It is the temperature at which a

matter begins to change from a liquid state to a gaseous state.

Note :Each substances have different boiling

point (water boil at 100 ).Life applications :Separation of the components of

petroleum oil depends on the difference between them in their boiling points.

5- Hardness:

Some solid substances

Soft at room temperature:

Ex: rubber

Need heat to be soft and easy to shaped

Ex: metals

Do not melt by heating

Ex : coal - sulphur

Life applications :

1- the screwdrivers are made of steel iron

because it is very hard. 2- the rods used in building houses

concrete are made of iron not copper. because the hardness of iron is

more than that of copper.

6- Electric conductivity:Good conductors

of electricity.Substances allow

electricity of flow through.

Ex: acidic solutions

Alkaline solutionsSome salt solution Metals as iron

Bad conductors of electricity.

Substances do not allow electricity to flow through.

Ex: gases Sugary solution

solution of hydrogen chloride in benzene

Sulphur – phosphorus.

Life applications:

1- electric wires are made of copper or aluminum and cover by plastic layer.

2- screwdrivers are made of steel iron, while their handles are made of wood or plastic.

Thermal conductivity:

Good conductors of heat

substance that allow heat to flow through

Ex: metals iron – copper aluminum.

Bad conductors of heat

Substances that do not allow heat to flow through

Ex: wood - plastic

Life applications:

1- cooking pans are made of aluminum

because it is good conductor of heat and has high melting point and easy to transfer heat.

2- handles of cooking pans are made of wood or plastic

because wood and plastic are bad conductors of heat.

Chemical propertiesMetals classified according to their

chemical activity into:

Very active metals

Metals react with oxygen as soon as being exposed to humid air.

Ex sodium-potassium

Less active metals

Metals they are metals which react with oxygen if left in air for some days it is rust.

Ex: iron

In active metals

Metals react with oxygen very difficult

Ex: silver- nickel

Give reasons:1- sodium and potassium are kept under

kerosene surface. to prevent their reaction with atmospheric

oxygen.2- steel bridges and the holders of light bulbs

painted from time to time to protect them from rust and corrosion 3- metallic spare parts of cars are covered with

grease. to protect them from rust and corrosion.4- washing of cooking pans made of aluminum

with a rough material . to remove any layer formed on them.

Give reasons:

5- silver and gold are used in making jewels.

because they are chemically poor active .

6-nickel,gold and silver are used to cover other substances which rapidly gain rust.

to protect them from corrosion.