Chemistry Reference
In-Depth Information
CHEMISTRY
P
C
ROPERTIES
AND
HANGES
Properties
Characteristics of a substance
Physical properties
Observable characteristics such as density, color,
smell, hardness, solubility, etc.
Chemical properties
Properties of a substance that cause specific behavior
during chemical reactions
Chemical reaction
Any change that alters the chemical properties of a
substance or forms a new substance
Reactants
The substances present at the beginning of a chemical
reaction
Products
The substances formed in a chemical reaction
One of the important tasks of chemistry is to study how substances can be
identified or distinguished from each other, that is, a study of properties.
Such studies are also essential in determining how substances can be used
in human endeavors.
There are two types of physical properties:
qualitative
properties and
quantitative
properties. Qualitative properties are those that cannot be mea-
sured, such as smell or taste. Quantitative properties, on the other hand, can
be given precise mathematical values, for example, the weight of a certain
volume of a substance (density), the temperature at which the substance boils
(boiling point), or electrical conductivity.
Chemical properties depend on the ways in which a substance interacts
(reacts) with other substances. Sulfuric acid reacts with iron to form iron sulfate
and hydrogen.
Iron
+
Sulfuric acid
Iron sulfate
+
Hydrogen
This is a chemical reaction. The fact that iron reacts when it comes into
contact with sulfuric acid is a chemical property of iron. Conversely, the
ability of sulfuric acid to affect iron is a chemical property of sulfuric acid.
The sulfuric acid and iron are called
reactants
in the above equation, and
the iron sulfate and hydrogen are the
products
of the reaction.
