Reaction rate

Reaction rate is a measure of how quickly a chemical reaction occurs. It is defined as the change in concentration of a substance in a given period of time. The rate of a reaction can be influenced by a number of factors, including the concentration of reactants, temperature, pressure, and the presence of a catalyst.

Definition

The reaction rate is defined as the change in concentration of a reactant or product per unit time. It is usually expressed in moles per liter per second (mol/L/s). The rate of a reaction can be determined by measuring the change in concentration of a reactant or product over time.

Factors affecting reaction rate

Several factors can affect the rate of a chemical reaction. These include:

• Concentration: The rate of a reaction generally increases with increasing concentration of reactants. This is because a higher concentration of reactants leads to more frequent collisions between the molecules, which can lead to more reactions.

• Temperature: Increasing the temperature increases the rate of a reaction. This is because at higher temperatures, molecules have more kinetic energy and therefore collide more frequently and with greater energy, leading to more reactions.

• Pressure: For reactions involving gases, increasing the pressure increases the rate of reaction. This is because increasing the pressure decreases the volume in which the molecules are spread out, leading to more frequent collisions and therefore more reactions.

• Catalyst: A catalyst is a substance that increases the rate of a reaction without being consumed in the reaction. It does this by lowering the activation energy for the reaction, allowing the reaction to occur more easily.

Rate equation

The rate of a chemical reaction can be described by a rate equation, which relates the rate of the reaction to the concentrations of the reactants. The rate equation for a reaction is usually determined experimentally.

See also

• Chemical kinetics
• Rate-determining step
• Arrhenius equation

Reaction_rate

• 
  Rust
• 
  Large bonfire
• 
  Reaction coordinate diagram