III. Read the following text. What is the meaning of the words and word-combinations
in bold?
TEXT B
CLASSIFICATION OF ORGANIC COMPOUNDS
The concept of functional groups is central in organic chemistry, both as a means to
classify structures and for predicting properties. A functional group is a molecular module,
and the reactivity of that functional group is assumed, within limits, to be the same in a
variety of molecules. Functional groups can have decisive
influence on the chemical and physical
properties of organic
compounds. Molecules are classified on the basis of their
functional groups. Alcohols, for example, all have the
subunit C-
O-H. All
alcohols tend to be somewhat hydrophilic, usually
form esters, and usually can be converted to the corresponding
halides. Most
functional groups feature heteroatoms (atoms
other than C and H). Organic compounds are classified according
to functional groups: alcohols, carboxylic acids, amines, etc.
Substances consisting entirely of
single-bonded carbon
and hydrogen atoms and lacking functional groups are called
alkanes. There are three basic
types of structure that they are classified in: the
linear straight-chain alkanes,
branched
Достарыңызбен бөлісу: 
