in this module will discuss about the condition for the chemical change . what are the factors are responsible for the chemical change. and idea of catalyst

1. We will discuss in this module
1) What is chemical change ?
2) Chemical bond ( just idea)
3) Condition for the chemical change
4) Positive and negative catalyst

2. Chemical change
 Chemical change is the transformation of one or more
substances into new substances with new properties.

3. Chemical bond
It a bond that holes the atoms
of molecule in compound

4. Condition for the chemical change
A) Mixing /close contact
chemical reaction happens only when a
substance is mixed with another substance
.means when a substance comes in
contact with anther substance Example
HCl + NaOH NaCl + H2O

5. B) Surface Area when the surface area of reactants are big, the rate of
chemical reaction increases because close contact
increases

6. Solutio
n
Some chemical reaction occurs only when the
chemicals are mixed or in molten state

7. C) Pressure:
Some chemical reaction takes place only by applying
the pressure. The certain amount of pressure is
necessary for them to conduct the reaction.

8. D)Heat: There are various reactions that take place only under the certain
temperature. When heat is supplied to the reactants they go under
reaction as heat also increases the rate for the chemical reaction

9. E) Light Light is also one of the factors that stimulate the rate of
reaction. There are some reactions that undergo only in the
presence of light

10. F) Electricity Most of the polarized molecule decomposes(breaks
into ions) on passing electricity

11. G) Catalyst A chemical substance that changes the rate( increase or
decrease ) of chemical reaction without undergoing any
permanent changes during the course of the chemical
reaction is said to be a catalyst.
The catalytic converter in a car contains
platinum, which serves as a catalyst to
change carbon monoxide, which is toxic,
into carbon dioxide.
TYPES OF CATALYIST

13. Properties of Catalyst
1. Catalyst does not change in its mass and chemical composition
during the chemical reaction.
2. Catalyst can be in a small quantity
3. Catalyst changes the rate of chemical reaction but does not
initiate the chemical reaction