4. Language development.

1. Fill in the gaps with the words from the list.

properties, alteration, occur, comprise, quantity, bond, join, particle, unique, reaction, solution, equilibrium

1. All the chemical elements differ by their physical and chemical

2. The ... of mercury with water may lead to very negative conse­quences.

3. Natural ... was destroyed because of government experiments with ecosystems.

4. This specimen is ..., I have never seen anything like this.

5. Two these elements have ionic ..., that is why they together form a very stable complex substance.

6. Be very careful when you work with ... of hydrochloric acid, you can burn yourself.

7. When different elements bind together, they undergo chemical ... .

8. The science of chemistry ... many different but nonetheless very important fields.

9. When a pharmacist is preparing a drug, he must think not only of ..., but of quality too.

10. As a result, many subsequent changes may ... .

2. Answer the following questions.

1. What is chemistry?

2. What do chemists study?

3. What are chemical changes?

4. What is the difference between chemical and physical changes?

5. How do chemical elements differ from each other?

6. How many elements arc there on the Earth: natural and artifi­cially synthesized?

7. What is analytical chemistry? Why is it important to study quanti­tative and qualitative analysis?

8. What professions is biochemistry especially important for?

9. What tools are used in colloid chemistry?

10. What is the difference between organic, inorganic chemistry and biochemistry?

5. Speaking.

1. Make questions for the answers. Then, in pairs, act out the dialogue.

• _____________________________________________________?

• Chemistry is the study of substances.

• _________________________________________________________?

• There are many fields of chemistry, analytical chemistry, bioche­mistry, chemical engineering, organic and inorganic chemistry, electrochemistry.

• _____________________________________________________________?

• Analytical chemistry determines the identity and quantity of each

element or compound present in a substance.

• _____________________________________________________________?

• Biochemistry is the study of the chemical composition of living matter and of the chemical processes that occur in living organ­isms.

- ________________________________________________________?

• Inorganic chemistry is the study of all elements and compounds that do not contain carbon. These include metals, halogens, and alkalies. Organic chemistry is the study of carbon and its com­pounds.

• ________________________________?

• Nuclear chemistry is the study of radioactivity, atomic nucleus, and nuclear reactions, and the development of applications for radioactive isotopes in rncdicine and industry.

• __________________________________________________________?

• Physical chemistry is the application of physical methods to the study of chemical problems.

2. Give as much information as you can about:

• fields of chemistry;

• possibilities of career in different fields of chemistry;

• modern branches of chemistry like biochemistry and chemical en­gineering.