Oxygen Lenka Šibravová, Soňa Konečná

OXYGEN OXYGEN the element is very common major component of air the second largest single component of the earth's atmosphere (21% by volume) the atmosphere of Mars contains only about 0.15% oxygen usually bound with other elements produced by plants during photosynthesis necessary for aerobic respiration plant = rostlina necessary = nutný, nezbytný bound = vázaný photosynthesis = fotosyntéza

Properties Name : Oxygen Name : Oxygen Symbol : O Symbol : O Atomic number : 8 Atomic number : 8 Atomic weight : Atomic weight : Group number : 16 Group number : 16 Group name : Chalcogen Group name : Chalcogen Period number : 2 Period number : 2

Properties heavier than air soluble in water without smell or taste the gas is colourless, odourless and tasteless chemical bonds with almost all other elements three isotopes heavy = těžký soluble = rozpustný taste = chuť

Property Property liquid O 2 and solid O 2 have a light blue color highly paramagnetic electronegativity highly oxidizing releasing heat release = uvolnit liquid = kapalný solid = pevný Liquid oxygen

Properties Properties the shell structure of oxygen crystal structure of oxygen.

History Discovered by: Joseph Priestley, Carl Scheele Discovered by: Joseph Priestley, Carl Scheele Discovered at: England, Sweden Discovered at: England, Sweden Discovered when: 1774 Discovered when: 1774 Joseph Priestley Joseph Priestley

Preparation large number of different methods for its preparation large number of different methods for its preparation 1) Preparation of oxygen using potassium chlorate 2 KClO 3 ==> 2 KCl + 3 O 2 2 KClO 3 ==> 2 KCl + 3 O 2 2) Preparation of oxygen using hydrogen peroxide 2 H 2 O 2 ==> 2 H 2 O + O 2 2 H 2 O 2 ==> 2 H 2 O + O 2 use = použít potassium = draslík

Preparation 3) Preparation of oxygen by electrolysis of water 2 H 2 O ==> 2 H 2 + O 2 2 H 2 O ==> 2 H 2 + O 2 4) Preparation of oxygen by the decomposition of salts 2 KNO 3 ==> 2 KNO 2 + O 2 2 KNO 3 ==> 2 KNO 2 + O 2 5) Preparation of oxygen from air electrolysis of water = elektrolýza vody decomposition of salts = rozklad solí

Compounds oxygen is very reactive oxygen forms chemical bonds with almost all other elements oxygen derivatives are prone to form free radicals the most common oxidation numbers are -2 chemical bond = chemická vazba prone = náchylný, nakloněný free radicals = volné radikály oxidation numbers = oxidační číslo

Compounds Hydroxide Aluminium hydroxide, Al(OH) 3 Aluminium hydroxide, Al(OH) 3 Barium hydroxide, Ba(OH) 2 Barium hydroxide, Ba(OH) 2 Oxide Oxide Carbon dioxide, CO 2 Carbon dioxide, CO 2Water has the chemical formula has the chemical formula H 2 OH O Alcohols (R-OH) methanol, CH 3 OH methanol, CH 3 OH Methanol burns in air forming carbon dioxide and water: 2CH 3 OH + 3 O 2 → 2CO 2 + 4H 2 O

Ozone allotropic form of oxygen allotropic form of oxygen important component of the atmosphere important component of the atmosphere effect on the ozone layer effect on the ozone layer ozone is toxic! ozone is toxic! used for drinking water treatment used for drinking water treatment important = důležitý layer = vrstva drinking water = pitná voda treatment = léčba

Applications  oxygen is essential to respiration  used in medicine  used in welding  making of steel and methanol essential = nezbytný weld = svářet kovy steel = ocel

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