6 A. There are words that sound 8 Wh
Εχ
same. We call them "international" words. Read the text and find in it
No living thing or group of living things can live and grow in iso.
Tation ſaisəʻleiſən]. All organisms, both plants and animals, need!
energy to develop and all species of living things influence the
lives of others. Ecology is a science. It studies how plants, ani.
their environment. People have always studied living things in
What Is Ecology?
mals and other living things live in relation to each other and to
their natura) ['nætſərəl] environment, in other words, they have al-
ways studied the air, the water, the soil and all the other things
that surround a person, animal or plant. The environment can in.
fluence the growth and health of living things. Ecologists also
study what happens to different species. They collect information
[info”meiſən] about their population number, diet ['darət], form,
size and behaviour. Ecology is one of the most important sciences
nowadays. It teaches us how to survive in the modern world.
1
cao
B. Listen to the tape, @ (47), and read the text again after it.
A. Read the text "What Is Ecology ?" again and complete the sentences.
1) Ecology is a science
6.перевод
2)2С6Н6 +15О2 = 12СО2 + 6Н2О
3)С7H8 + 9O2 = 7CO2 + 4H2O
4)2C6H5COOH +Na2CO3 =2C6H5COONa +CO2+H2O
Бензол и толуол
При окислении толуола перманганатом калия образуется бензойная кислота
M(C6H5CH3)=92г/моль
M(С6Н6)=78г/моль
M(C6H5COOH)=122г/моль
n(C6H5COOH)=14.64г/122г/моль=0,12моль
по уравнению 4 : n(CO2) = n(C6H5COOH)/2=0.06моль
Значит при сжигании смеси получилось 0,06моль*20= 1,2моль
По уравнению 1 : n(C6H5CH3) =n(C6H5COOH)=0,12моль
m(C6H5CH3)=92г/моль *0,12моль=11г
n(CO2) = 7*n(C6H5CH3)=0.12моль*7= 0,84моль газа образовалось в реакции горения толуола, значит в реакции горения бензола образовалась 1,2моль - 0,84моль=0,36моль
В свою очередь по уравнению 2: n(С6Н6)=0,36моль/12 *2=0,06моль
m(С6Н6)=0.06моль*78г/моль=4,68г
m(общая)=4,68г+11г=15,72г
W%=m/m(общ) *100%
W%(С6Н6)=4.68г / 15,72г *100 =30% (0,3)
W%(C6H5CH3)=11г / 15,72г *100=70% (0,7)