University:
High School
Course:
High School Chemistry
Academic year:

2019
Views:

481

Pages:

4
Author:

susurros3z

reaction rate: the change in Concentration of the Reactants per unit time speed at which Reactants disappear and Products appear The study of reaction rates is called Chemical Kinetics. ✓ In order for a reaction to occur, reacting Particles must collide effectively. ✓ In an effective collision, the reactant particles collide with the correct orientation and the proper amount of energy Factors Affecting Reaction Rates: a. Nature of Reactants: The stability of the reactants, types of bond involved, and state of ma er all affect reaction rates. b. Concentration of reactants: 3M HCl → more conc than 1M HCl Increasing the concentration of reactants → more effective collisions → increased rate of reaction Increasing the Pressure of the reactants (GASES only) → increases the Concentration of reactants → increases effective collisions c. Temperature of reactants: ↑x → more collisions ↑x → more effective collisions increasing SPEED of reactants → more effective collisions → increased rate of reaction. d. Catalyst: Lowers activation energy a substance that changes the rate of a reaction without being permanently altered increases the rate of a reaction by lowering the required amount of energy to achieve effective collisions e. Surface area of reactants: increasing surface area → more effective collisions → increased rate of reaction. A study of reaction Rates is called chemical Kinetics Reaction rate refers to how quickly or slowly the reactants disappear and the Products appear. It is measured in terms of the disappearance of the reactants. If a reaction is to occur, reacting particles must first collide and this collision must be effective. What are the TWO characteristics of an effective collision? → proper orientation (angle) → enough energy What are the FIVE major factors that affect reaction rate? → Nature of reactants → Concentration (Pressure on Gas) → Temperature → Catalyst → Surface area Why would a mixture of gases react faster when the volume they occupy is decreased? Decrease VI → push molecules closer together → INC concentration → More collisions Why would iron filings rust faster than an iron nail? → Filings have more surface area → More exposed iron molecules to rust What is the effect of a catalyst on the required energy to achieve effective collisions? → Lowers activation energy → NOT more collisions, but more effective collisions