Rate of chemical reaction

1. Ministry of Science and Higher Education of the Republic of Kazakhstan Sh.
Ualikhanov Kokshetau university
Pedagogical Institute
Department of Chemistry and Biotechnology
«RATE OFCHEMICALREACTION»
The report was completed by the students:
Serikbay Aruzhan
Mendesh Altinay
Sedunova Nina
Boranbaeva Ainur
Kokshetau 2023

2. Content
1. Rate of chemical reaction
2. Factors That Affect Rate

3. Rate of chemical reaction
The rate of a chemical reaction is the change in the concentration of
reactants per unit time. Chemical reactions occur at different rates. In
addition, the same reaction can proceed quickly under some conditions, for
example, at elevated temperatures, and slowly under others, for example,
upon cooling; Moreover, the difference in the speed of the same reaction
can be very large.

4. It is divided into homogeneous and heterogeneous systems.
Rate of
chemical
reaction
The rate of a
homogeneous
reaction is the amount
of substance that
reacts or is formed
during a reaction per
unit time per unit
volume of the system.
The rate of a
heterogeneous
reaction is the amount
of substance that reacts
or is formed during a
reaction per unit time
per unit surface area of
the phase.

5. Factors That Affect Rate
Reactant
concentration
Physical state of
the reactants and
surface area
Temperature
Pressure
Presence of
a catalyst

6. Reactant concentration
Increasing the concentration of one or more reactants will often increase
the rate of reaction. This occurs because a higher concentration of a
reactant will lead to more collisions of that reactant in a specific time
period.

7. Physical state of the reactants
and surface area
If reactant molecules exist in different phases, as in a heterogeneous mixture,
the rate of reaction will be limited by the surface area of the phases that are in
contact. For example, if a solid metal reactant and gas reactant are mixed, only
the molecules present on the surface of the metal are able to collide with the
gas molecules. Therefore, increasing the surface area of the metal by pounding
it flat or cutting it into many pieces will increase its reaction rate.

8. Temperature
The higher the temperature, the faster the reaction occurs. For example,
copper(II) oxide reacts very slowly with dilute sulfuric acid, and when heated,
the reaction rate increases markedly, as evidenced by the dissolution of black
copper(II) oxide in the acid to form a blue solution.

9. Pressure
Pressure increases the gases concentration resulting in the increase of the rate of
reaction. The increase in the pressure on a reaction involves the reacting gases
increasing the rate of reaction. And modifying the pressure on a reaction
involving solids or liquids only has no effect on the reaction rate.
For instance,
In the case of manufacturing ammonia using the Haber Process, the reaction rate
between nitrogen and hydrogen is increased using very high pressures.
𝐻2 (𝑔)+3 𝐻2 ¿2𝑁𝐻3(𝑔)

10. Presence of a catalyst
A catalyst is a substance that accelerates a reaction by participating in it without
being consumed. Catalysts provide an alternate reaction pathway to obtain
products. For example, When potassium chlorate is heated, it readily decomposes
to give dioxygen. This decomposition occurs at high temperatures- 653-873K.
When manganese dioxide is added, decomposition takes place at a lower
temperature and a much faster rate. The catalyst, manganese dioxide thus
accelerates the chemical reaction while itself remaining unchanged throughout
the reaction. Here manganese oxide acts as a catalyst.

11. Thank You !