I. Read and translate the text B. Mention the criteria for the classification of compounds
Text B. Classification of Compounds
Chemical compounds may be classified according to several different criteria. One common method is based on the specific elements present. For example, oxides contain one or more oxygen atoms, hydrides contain one or more hydrogen atoms, and halides contain one or more halogen (group 7) atoms. Organic compounds are characterized as those compounds with a backbone of carbon atoms, and all the remaining compounds are classified as inorganic. As the name suggests, organometallic compounds are organic compounds bonded to metal atoms.
Another classification scheme for chemical compounds is based on the types of bonds that the compound contains. Ionic compounds contain ions and are held together by the attractive forces among the oppositely charged ions. Common salt (sodium chloride) is one of the best – known ionic compounds. Molecular compounds contain discrete molecules, which are held together by sharing electrons (covalent bonding). Examples are water, which contains H2O molecules; methane, which contains CH4 molecules; and hydrogen fluoride, which contains HF molecules.
A third classification scheme is based on the reactivities of compounds – specifically, the types of chemical reactions that the compounds are likely to undergo. For example, acids are compounds that produce H+ ions (protons) when dissolved in water to produce aqueous solutions. Thus, acids are defined as proton donors. The most common acids are aqueous (water) solutions of HCl (hydrochloric acid), H2SO4 (sulfuric acid), NO3 (nitric acid), and H3PO4 (phosphoric acid). Bases, on the other hand, are proton acceptors. The most common base is the hydroxide ion (OH-), which reacts with an H+ ion to form a water molecule.
H+ + OH --- HOH (usually written H2O).
II. Find the English equivalents in the text:
в соответствии с несколькими различными критериями; основывается на; все остальные соединения; органические соединения связаны с атомами металлов; положительно заряженные ионы; хорошо известные ионные соединения; реактивность соединений; образуют водные растворы; растворяются в воде; самая распространенная основа
III. Find the synonyms:
content, rich, quantity, to lower, to carry, danger, to decrease, abundant, threat, to tend, to accumulate, level, to transport, to have a tendency, burden, load, to pile up, amount
|
|
|
LESSON 9
Грамматика: неопределеннее местоимения и их производные; both … and …; thus
CHEMICAL REACTIONS
Запомните:суффикс – sion – образует существительные от глагольных корней. - tion, - ssion - его варианты.
I.1. Прочитайте и переведите:
consultation, occlusion, attention, invasion, occupation, obstruction, titration, solution, condition, contamination, distillation, proportion, possession, decision, commission,
II. 2. Прочтите и подберите к каждому существительному из списка А соответствующее ему по смыслу прилагательное из списка В:
А. heart, lungs, kidneys, stomach, intestine, brain, blood, vessel, gland, muscle
B. hepatic, cerebral, gastric, colic, haemal, vascular, nephritic, cardiac, pulmonary, glandular, muscular
III. Постойте вопросительную, утвердительную или отрицательную форму следующих предложений, содержащих неопределенные местоимения.
- There are some students in the classroom.
- I want to go to some interesting places on Sunday.
- Have you got any relatives abroad?
- We have some scientific papers on the shelves.
- They often read some English newspapers.
- There are some students in the dissecting-room.
- Some scientists were present at the meeting.
- There was some new material in the lecture yesterday.
V. Дополните таблицу недостающими формами производных местоимений some, any, no, every и переведите их.
| thing | body | one | where | ||
| 1 | some | something | - | - | - |
| 2 | any | - | anybody | - | - |
| 3 | no | - | - | no one | - |
| 4 | every | - | - | - | everywhere |
|
|
|
V. Поставьте предложения с производными местоимениями some, any, no, every сначала в вопросительную форму, а затем в отрицательную.
1. I know something about it.
2 Somebody must estimate red blood cells.
3. He wants to go somewhere on Sunday.
4. Everybody must come to the meeting.
5. Someone was discharged from the hospital yesterday.
6. We have discovered something new in the treatment of this disease.
7. Somebody can help us.
8. I see our students everywhere.
Дата добавления: 2018-02-28; просмотров: 381; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!