Can you name the discoverer(s) of oxygen? When was it discovered?

The following list may help you: C. W. Scheele, G. E. Stahl, J. Mayow, A. Lavoisier, J. Priestley, Leonardo da Vinci, R. Hooke, P. Bayen, R. Boyle, J. Dalton, H. Davy, J. Dewar, A. Avogadro.

What do you know about the phlogiston theory?

What are the applications of oxygen?

 

Match the following properties and characteristics of oxygen with their numeric expressions.

Atomic number, allotropes, electron configuration, melting point, group, oxidation states, density, relative atomic mass, boiling point, isotopes, period, discovery year, electronegativity (Pauling scale).

−297.332°F; 8; 16O, 17O, 18O; −218.79º C; 1.429 g/l; 2;16; +2, +1, −1, −2; 3.44; 15.999;[He] 2s22p4; 1774; O2, O3.

TEXT A

Memorize the meaning of the following words and word combinations.

abundant, account, accumulate, algae, acid, acidic, amateur scientist, on the average, combustion, be a component of smth., compound, (modern) concept, consist in smth., constituent, dioxide, establish, estimate, find evidence, free state, make up, multitude, obtain, occurrence, oxygen, oxide, work of one’s own, particularly, perform an experiment, publication, pure, react, an acidic solution, soluble, split into, as well as, yield products

 

Practise your pronunciation.

Photosynthesis, algae, amateur, biomass, component, compound, oxide, dioxide, phlogiston, dephlogisticated, yield, occur, occurrence, the earth's crust, various, multitude.

 

Match the words on the left with the definitions on the right.

A			B
1.	combustion	a)		happen, take place, be found
2.	concept	b)		a general notion or idea
3.	constituent	c)		rapid oxidation accompanied by heat and, usually light
4.	solution	d)		the quantity of product formed by the interaction of two or more substances, generally expressed as a percentage of the quantity obtained to that theoretically obtainable
5.	yield	e)		data that tend to prove or disprove something, ground for belief
6.	amateur	f)		a homogeneous, molecular mixture of two or more substances
7.	abundant	g)		divide into distinct parts or portions
8.	split	h)		a component part, ingredient
9.	occur	i)		inexperienced or unskilled in a particular activity
10.	evidence	j)		present in great quantity, more than adequate, oversufficient

4. Read and translate the text.

 

OXYGEN

 

Oxygen first appeared in the Earth's atmosphere around 2 billion years ago, accumulating from the photosynthesis of blue-green algae. Photosynthesis uses energy from the sun to split water into oxygen and hydrogen. The oxygen passes into the atmosphere and the hydrogen joins with carbon dioxide to produce biomass. When living things need energy they take in oxygen for respiration. The oxygen returns to the atmosphere in the form of carbon dioxide. Oxygen gas is fairly soluble in water, which makes aerobic life in rivers, lakes and oceans possible. Oxygen occurs in the free state as the second most abundant component of the atmosphere; about one-fifth of the air by volume is oxygen. In the combined state it makes up 88.81% by weight of pure water, and, on the average, 85.79% of sea water. It occurs in the earth's crust, in the form of a multitude of compounds, to the estimated extent of 46.43%.

Credit for the discovery of oxygen is shared by two men, Joseph Priestley, an English clergyman and amateur scientist, who later moved to the United States to escape religious persecution, and Carl Wilhelm Scheele, a Swedish pharmacist. Working independently, these two men both obtained the gas which we know as oxygen by heating various compounds of the element, particularly mercuric oxide. They also found evidence that this gas is a component of the atmosphere. Priestley's work was published in 1774, but although Scheele's experiments had probably been performed even earlier, their publication was delayed and no account of them appeared until 1777. Though Priestley recognized that the gas which he had discovered plays an important role in combustion, he remained, along with Scheele, an ardent adherent of the phlogiston theory of combustion; in fact, he called the gas "dephlogisticated air". Phlogiston was then thought to be some kind of primordial substance that was the root cause of combustion.

On the basis of the experimental results of Priestley, Scheele, and others, as well as some very fine experimental work of his own, in 1777 the brilliant French chemist Antoine Lavoisier established the modern concept that the combustion of a substance consists in its combination with the new gas which Priestley and Scheele had described, and which Lavoisier found an important constituent of the atmosphere. Since the combustion of many substances (now known as non-metals) such as phosphorus and sulphur yields products which react with water and give acidic solutions, Lavoisier named this gas oxygen, derived from Greek words meaning "acid former".