М. М. Кутепова The World of Chemistry Мир

Listen to the following dialogue and say what problems the participants are discussing. The notes and words will help you to understand the text better:

NOTES

1. 
   don’t follow me — не успеваете за мной
   
2. 
   to begin with — начнем с того, что
   
3. 
   you mean — вы имеете в виду
   
4. 
   it’s not as simple as that - не так все просто
   
5. 
   it should be noted — следует отметить
   
6. 
   sorry to interrupt — простите, что перебиваю
   
7. 
   absolutely true — абсолютно верно
   
8. 
   I have a point to make here — здесь я хочу сказать
   
9. 
   as far as I know — насколько я знаю
   
10. 
    to a large extent — в большой степени
    
11. 
    to tell you the truth — по правде говоря
    
12. 
    see you later — до встречи
    

WORDS

abundant — распространенный odour - - запах approximately — приблизительно outstanding — выдающийся colour — цвет pale -- бледный
to compress — сдавливать, сжимать slightly — слегка, немного dust — пыль supporter - сторонник; зд. тот,
main — главный, основной кто поддерживает
negligible -- незначительный taste - вкус


С. S.: Good afternoon. Гт Carl Spider and today we’re going
to discuss oxygen. If you don’t understand or follow me, or if you have anything to add, you’re welcome to interrupt. O.K.? Well, to begin with, it’s common knowledge, oxygen is the most abundant element on our planet...
STUDENT I: May I interrupt you for a moment? When was it isolated?
C. S.: You mean discovered? It’s a good question, \\fell, it was
discovered by Priestley as early as 1774. But it’s not as simple as that. Because Lavoisier also made experiments with oxygen isolating it from air and developing Priestley’s work. Lavoisier emphasized the role of oxygen in combustion and respiration. Well, coming back to what I was saying, in nature oxygen may occur in a free state or may be found combined with other elements. It should be noted, that because of its chemical properties it has been called the most important of all elements to man.
STUDENT 2: Sorry to interrupt you, bul is it because of being a supporter of combustion and of forming oxides with both metals and nonmetals?
C. S.: Quite right. Let me continue and say that oxygen is a
colourless, odourless, tasteless gas. It’s slightly heavier than air and is slightly soluble in water. Being compressed and cooled it can form a pale blue liquid boiling at - 192.98°C which would be slightly magnetic.
STUDENT I: 1 wonder if 1 could comment on the chemical property ofoxygen?


109

С. S.:

STUDENT 1:


С. S:
STUDENT 2: C. S.:
STUDENT 2: C S.:


STUDENT 2: C. S:


STUDENT 1: C. S.:
STUDENT 2: C. S. :
STUDENT 2:


C S.:
STUDENT 1:


C. S.:
STUDENT 2: C S.:


Do, please.
Well, the outstanding property of oxygen is its activity.
Correct? In other words, its tendency to combine with
other substances.
Absolutely true. It will combine with all the elements.
I have a point to make here...
Yes?
As far as I know, it doesn’t combine with inert gases,
does it?
Yes, quite correct. Before I could resume, would you
answer my question? What happens to oxygen with the
increase in temperature?
I guess, it would greatly increase the oxygen activity.
Yes, that’s true. Now, oxygen, silicon, aluminium and
hydrogen together constitute approximately 80 percent
of the Earth’s crust, sea and atmosphere.
May I interrupt you again, Dr. Spider? What about ni-
trogen?
Oh, yes. It’s the main element in the air, but it isn’t one
of the most common elements...
Could I say something about nitrogen?
I’d be delighted to hear.
Nitrogen forms only a small percentage of the crust and
oceans, and the mass of the atmosphere is negligible
compared to the total mass of the Earth.
It’s a good comment, I should say. Speaking about air,
could anybody tell me about its composition?
Oh, it varies and depends to a large extent on plants and
animals which control the amounts of oxygen and car-
bon dioxide by photosynthesis and respiration.
Good. What else does air contain? Anybody?
Water vapour and dust. If dust is removed, then... to tell
you the truth, I don’t remember the exact figures...
Well, the approximate composition by volume is the fol-
lowing: nitrogen — 78 percent, oxygen — 21 percent,
argon — 0.93 percent, carbon dioxide — 0.03 percent,
plus small quantities of other gases. Well, thank you for

your active participation. Next lime we’ll speak about combination of oxygen with metals. What do they form? STUDENT 2: Oxides, I suppose.

C. S.: Well done! See you later.

13.