2. • Chemical changes occur when a substance combines with
another to form a new substance, called synthesis or,
alternatively, decomposes into two or more different
substances. These processes are called chemical reactions
and, in general, are not reversible except by further
chemical reactions.
What is a Chemical
Cahnge
3. • Physical properties are properties of an element or compound that can be observed without a
chemical reaction of the substance. Density and electrical conductivity are examples of
physical properties.
• In a physical change, the substances are not altered chemically. No new products are formed.
Chemical bonds are not broken in a physical change
• A physical change can affect the size, shape or color of a substance but does not affect its
composition. The substances may be changed to another phase (i.e. gas, liquid, solid) or
separated or combined.
• Examples:
• when ice melts
• when sulfur is mixed with iron filings.
• breaking a glass
• dissolving sugar in water
What is a Physical
Change
4. • Condensation is the change of the physical state of matter
from gaseous phase into liquid phase, and is the reverse
of vaporization. When the transition happens from the
gaseous phase into the solid phase directly, the change is
called deposition.
• It apparatus is the reflux
Condensation
5. • Distillation is a widely used method for separating
mixtures based on differences in the conditions required
to change the phase of components of the mixture.
Destilation