Reaction Rates

RATES OF REACTION ARE INFLUENCED BY NATURE OF REACTANTS

Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so the particles stick together and don’t bounce off each other. The energy required is the “activation energy”. NATURE OF REACTANTS

RATES OF REACTION ARE INFLUENCED BY Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of the electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so so the particles stick together and don’t bounce off each other. The energy required is the activation energy. NATURE OF REACTANTS CONCENTRATION

The more particles, the more collisions, the more activated complexes formed, the faster the rate of reaction

RATES OF REACTION ARE INFLUENCED BY Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of the electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so so the particles stick together and don’t bounce off each other. The energy required is the activation energy. The more particles, the more collisions, the more activated complexes formed, the faster the rate of reaction. Nature of Reactants Concentration Temperature

TEMPERATURE The greater the temperature the faster the particles move. The faster the particles move the more collisions. The collisions also have greater energy so more collisions have sufficient energy to form activated complexes. More activated complexes mean a faster reaction rate.

RATES OF REACTION ARE INFLUENCED BY Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of the electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so so the particles stick together and don’t bounce off each other. The energy required is the activation energy. The more particles, the more collisions, the more activated complexes formed, the faster the rate of reaction. Nature of Reactants Concentration Temperature The greater the temperature the faster the particles move. The faster the particles move the more collisions. The collision also have greater energy so more collisions have sufficient energy to activated complexes. More activated complexes mean a faster reaction rate. Catalyst

CATALYST Catalyst are substances which speed up the rate of a reaction with out themselves being changed Catalyst act by lowering the activation energy required thereby increasing the rate of the reaction.

RATES OF REACTION ARE INFLUENCED BY Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of the electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so so the particles stick together and don’t bounce off each other. The energy required is the activation energy. The more particles, the more collisions, the more activated complexes formed, the faster the rate of reaction. Nature of Reactants Concentration Temperature The greater the temperature the faster the particles move. The faster the particles move the more collisions. The collision also have greater energy so more collisions have sufficient energy to activated complexes. More activated complexes mean a faster reaction rate. Catalyst Catalyst are substances which speed up the rate of a reaction without themselves being changed. Catalyst act by lowering the activation energy required thereby increasing the rate of the reaction. Reaction Mechanism

For the reaction A + B + C + D  ABCD, it is unlikely that all four particles would collide at the same time with exactly the right speed and angle so the four particles would stick together forming an activated complex. Instead reactions are made up of a series of steps each requiring only two particles to collide to form the activated complex. For the above example: A + B  AB AB + C  ABC ABC + D  ABCD Generally speaking, the more steps required, the slower the reaction rate.

RATES OF REACTION ARE INFLUENCED BY Ionic compounds are formed more or less instantaneously while covalent compounds require the rearrangement of the electrons to form the necessary bonds. For a reaction to occur, two particles must collide to form an activated complex which will then form the necessary product. Such collisions must be at exactly the right speed and angle so so the particles stick together and don’t bounce off each other. The energy required is the activation energy. The more particles, the more collisions, the more activated complexes formed, the faster the rate of reaction. Nature of Reactants Concentration Temperature The greater the temperature the faster the particles move. The faster the particles move the more collisions. The collision also have greater energy so more collisions have sufficient energy to activated complexes. More activated complexes mean a faster reaction rate. Catalyst Catalyst are substances which speed up the rate of a reaction without themselves being changed. Catalyst act by lowering the activation energy required thereby increasing the rate of the reaction. Reaction Mechanism For the reaction A + B + C + D  ABCD, it is unlikely that all four of the particles would collide at the same time with exactly the right speed and angle so that the four particles would stick together forming an activated complex. Instead reactions are made up of a series of steps each requiring only two particles to collide to form the activated complex. For the above example: A + B  AB AB + C  ABC ABC + D  ABCD Generally speaking, the more steps, the slower the reaction rate.