The document discusses chemical reactions and factors that affect reaction rates. It states the collision theory, which says that reaction rates increase with more frequent collisions between reactant particles that have sufficient kinetic energy. The document defines reaction rate and explains how increasing temperature, concentration, and surface area, or using a catalyst, can increase reaction rates by enhancing collisions between reactants.

2. Chemical Change

7. OBJECTIVES:
At the end of 60-minute discussion, you are expected to:
State the collision theory
Explain the effects of concentration, temperature, &
particle size on the rate of reaction
Define catalyst and describe how it affects reaction rate

9. a process that leads to the
transformation of one set
of chemical substances to another.
usually characterized by
a chemical change, and they yield
one or more products, which
usually have properties different
from the reactants.

10. CHEMICAL REACTIONS:
Reactant → Product
H2 + O2 → H2O

12. HOW DO CHEMICAL
REACTIONS
HAPPEN?

15. “The greater the frequency of
collisions,
the higher the rate of reaction.”

16. States that gas-phase
reaction occurs when
molecules colliding have
sufficient kinetic energy.

17. States that the rate of
chemical reaction is
directly proportional to the
number of collisions
between reactants.

18. The change in the
concentration of reactant
or product per unit o time.
-speed in which new
particles form

19. -speed in which new particles
form
N2 + O2 NO + NO
Bonds between atoms of the
reactants (N2 and O2 are
broken and new bonds (NO)
form

20. A chemical reactions occur when
collisions between molecules have
sufficient energy to break bonds in
the reactants
If the molecules collide with
proper orientation

21. A chemical reactions occur when
collisions between molecules have
sufficient energy to break bonds in
the reactants
If the molecules collide with
proper orientation

22. Activation energy is the
energy required to proceed
and reach the transition
state.

23. Reaction rate is intuitively
defines as how quickly or slowly
a reaction takes place.

24.  Temperature
 Surface area
 Concentration of reactants
 Catalyst

25. If the temperature is increased:
* the reactant particles move more
quickly
 * the reactant particles have more
kinetic energy
The reaction rate increases

26. Larger surface area would
have a larger space of
collision between particles
of a reaction.

28. If the concentration is
increased:
 the reactant particles
become more crowded
 there is a greater chance of
the particles colliding
 The rate of reaction
increases

30. -a substance
that makes the
chemical
reaction faster