oxygen

Green plants are the main source of oxygen

Oxygen is produced during the photosynthesis process in order compensate the consumption of oxygen in the respiration and combustion processes, so the earths vegetation should be maintained.

oxygen

oxygen

The atmosphere is composed of a mixture of gases surrounding the earth. They are attracted to the earth by gravity.Nitrogen 78%Oxygen 21%Carbon dioxide and other gases like (argon – neon – helium – water vapour) and other gases.

oxygen

oxygen

The atmosphere importance:

1) Protects the earth by absorbing ultraviolet radiation coming from outer space. 2) It adjusts the temperature of the Earth’s surface.

oxygen

oxygen

There are large quantities of solid objects in the atmosphere like (dust particles – smoke – gases) produced by factories – cars – trains – ships and they considered air pollutants.

They help in the condensing of water vapour around and falling in the form of drops of rains or snow.

oxygen

oxygen

Water rises into

cylinder with one fifth of its volume. This occurs as a result of air’s loss one of its components which is oxygen consumed by the candle during burning.

oxygen

oxygen

Hydrogen peroxide dissociates in the presence of manganese dioxide (as a catalyst) into water and oxygen gas (manganese dioxide remains without a change in quantity and properties and so it is a catalyst)

The properties of the

oxygen:1) Oxygen is a colorless, tasteless and odorless gas.2) It scarcely dissolves in water.3) It has a neutral effect on litmus paper with its two colors.4) Oxygen is heavier than air as it replaces the air.

oxygen

Oxygen is characterized by its ability to unite directly with most elements forming oxides. If this union is rapid and produces heat and light, it is named “burning” whereas if it is slow and in the presence of moisture (water), it is named “oxidation”

oxygen

Compare between the iron after and before exposure to moisture. This explains the erosion of ironware such as the bridges’ pillars. As time passes, if they are not isolated with paints, they cause damage.

oxygen

The cleansing wire gets burned because the outer surface of the wire is large enough to react with oxygen in the air. So, combustion occurs quickly. The wire becomes heavier after burning because oxygen combines with iron forming iron oxide.

oxygen

The importance and uses of oxygen:

Oxygen has importance to the human life and all living organisms.1) Water consists of oxygen united with hydrogen.

oxygen

2) Important in respiration and food combustion process inside living cells to produce energy necessary for vital processes.

oxygen

3) Ozone layer (O3)

oxygen

4) Oxygen gets compressed in iron cylinders and used in:

a. Mechanical ventilation for patients who suffer from breathing difficulties.

oxygen

b. During surgeries.

oxygen

c. During diving and climbing mountains. Because oxygen becomes lighter when we have rise above the earth’s surface.

oxygen

d. Oxygen is also used in cutting and welding metals when combined with acetylene gas to produce “oxy-acetylene” flame whose temperature reaches 3500⁰ C sufficient to melt metals.

Carbon dioxideCO₂

CO₂ is one of bases of the photosynthesis process that green plants make. During this process plants make nutrients for living organisms.

photosynthesis process for build plants bodies.

Carbon dioxideCO₂

The increase of the percentage of carbon dioxide in the air leads to suffocation of living organisms as well as global warming.

increase of CO₂ cause server harms to the earth’s climate and raises its temperature.

green plants share in decreasing ratio of CO₂ in the atmosphere.

Carbon dioxideCO₂

Carbon dioxideCO₂

Gas Slight percentage

0.03 % It consist of one

carbon atom linked with two oxygen atoms.

Carbon dioxideCO₂

CO₂ resources: CO₂ is emitted as a result

of the combustion of organic materials such as:

Wood Coal Oil Gasoline Tobacco (the material

cigarettes)

Carbon dioxideCO₂

In the recent years, it has been observed that the percentage of this gas in atmosphere is rising. This due to:

1) Burning of massive amount of fuel in industrial.

2) Means of transportation.3) Engines.4) Cutting plants.

Carbon dioxideCO₂

CO₂ turbid the clear limewater (calcium hydroxide) where white precipitate appears as a result of its reaction with CO₂ forming calcium carbonate which don't dissolve in water.

Turbidity of lime water is considered as detection of presence of CO₂

Carbon dioxideCO₂

Carbon dioxideCO₂

The properties of CO₂:1) It is colorless and

odorless.

2) G.R: It is heavier than air and so it is collected by displacing the air upward and replacing it

Carbon dioxideCO₂

3) G.R: It dissolves in water , so it is not collected by displacing water in preparing oxygen.

4) G.R: It does not burn and does not help in combustion so, it is used for extinguishing fires.

Carbon dioxideCO₂

5) G.R: The magnesium ribbon keeps burning, turns into a magnesium oxide (with white color and the carbon deposits on the wall of the cylinder.

Carbon dioxideCO₂

Importance and use of CO₂:

1) ) G.R: refrigeration on converting it into a liquid by pressure and cooling then pressure is relieved composing dry ice that we use in refrigeration.

Carbon dioxideCO₂

2) is used to make soft drinks.

3) In photosynthesis.

Carbon dioxideCO₂

5) It is used to make bread bubbled as yeast which produces CO₂ by fermentation when it is add. CO₂ gets expanded due to the heat making bread porous and tasty.

NitrogenN

Nitrogen: It is chemical

element found in nature in form of gas.

Symbol of nitrogen N₂ consist of two atoms of nitrogen.

NitrogenN

G.R: Nitrogen is also called (azote) which means lifeless.

Because:1- It doesn't help in burning.2- is not included in the process of respiration.

NitrogenN

Properties of nitrogen:

1. A colorless, tasteless and odorless gas.

2. hardly (scarcely) dissolves in water.

3. It is main component in all proteins.

4. It does not help in burning.

NitrogenN

5. Nitrogen can be condensed to a liquified state.6. When it combines with a lighted magnesium ribbon composing a white substance by adding a little water, a very pungent smell “ammonia “ emits

NitrogenN

NitrogenN

The existence of nitrogen:

Nitrogen represents 78% Nitrogen contributes in the

composition of all living tissues in all living organisms cause they need nitrogen to live as nitrogen composes the most important part in protein.

NitrogenN

NitrogenN

Nitrogen oxides are formed in the atmosphere during lightning which reaches soil with rain water. Legumes such as clover, peas and soybeans produce proteins from atmospheric nitrogen by the help of a specific type of bacteria that lives in their roots.

NitrogenN

The importance and uses of nitrogen:

1. Nitrogen is recently used in filling car tires for the relative constancy of its volume at the change of temperature.

NitrogenN

2.Liquid nitrogen is used in:a. Treatment to skin

tumors.b. Cooling food

products with the aim of preservation of transferring purposes.

NitrogenN

3. It contributes in composing gunpowder and ammonia nitrates included in the composition of soil fertilizers.

NitrogenN

4. It is commercially used in manufacture of ammonia to produce fertilizers.

NitrogenN

5. Nitrogen is used as an inactive material in the tanks of liquified explosives such as: petroleum, some flammable materials and during the manufacture of electronic devices.

NitrogenN

6. Nitrogen is used to make stainless steel.

7. Small amounts of nitrogen are used to fill some types of lamps.

NitrogenN