Rates of Reactions Review

Flashcards covering rates of reaction, collision theory, and factors influencing reaction rates.

Collision Theory

Collisions must have enough energy and be in the correct orientation/direction to result in a reaction.

Factors Affecting Reaction Rate

The four factors that can change the reaction rate are: concentration, surface area, temperature, and catalyst (or inhibitor).

Catalyst

A catalyst provides a different path for the reaction that requires less energy, thus speeding up the rate of a reaction.

Concentration and Reaction Rate

A higher concentration means more effective collisions where the reactants meet the minimum energy required, increasing the reaction rate.

Surface Area and Reaction Rate

Increased surface area exposes more particles to the reaction, allowing for a greater chance of effective collisions and a faster reaction rate.

Temperature and Reaction Rate

Higher temperatures cause particles to move faster, resulting in a greater chance for effective collisions and a faster reaction rate.

Activation Energy (Ea)

The minimum energy required for reactant particles to turn into product.

Catalyst in Reaction

A catalyst lowers the activation energy of a reaction, providing an alternate pathway which speeds up the reaction.

Inhibitor

A substance that slows down or prevents a chemical reaction.

Exothermic Reaction

A reaction that releases energy, resulting in the products having lower energy than the reactants (negative ΔH).

Endothermic Reaction

A reaction that absorbs energy, resulting in the products having higher energy than the reactants (positive ΔH).

Activation Energy (Ea)

The minimum energy required for reactant particles to turn into product.

Catalyst in Reaction

A catalyst lowers the activation energy of a reaction, providing an alternate pathway which speeds up the reaction.

Inhibitor

A substance that slows down or prevents a chemical reaction.

Exothermic Reaction

A reaction that releases energy, resulting in the products having lower energy than the reactants (negative ΔH).

Endothermic Reaction

A reaction that absorbs energy, resulting in the products having higher energy than the reactants (positive ΔH).

Rate Determining Step

The slowest step in a multi-step reaction, which determines the overall rate of the reaction.

Bond Energy and Reaction Type

Bond breaking requires energy (endothermic), while bond formation releases energy (exothermic). The overall energy change determines whether a reaction is exothermic or endothermic.

Arrhenius Equation

A mathematical expression that shows the relationship between the rate constant, temperature, activation energy, and frequency factor of a chemical reaction: k = Ae^{-\frac{E_a}{RT}}, where:

• k is the rate constant,
• A is the frequency factor,
• E_a is the activation energy,
• R is the ideal gas constant,
• T is the absolute temperature (in Kelvin).

Provide a surface for the reaction. Involve

Collision Theory

Collisions must have enough energy and be in the correct orientation/direction to result in a reaction.

Factors Affecting Reaction Rate

The four factors that can change the reaction rate are: concentration, surface area, temperature, and catalyst (or inhibitor).

Catalyst

A catalyst provides a different path for the reaction that requires less energy, thus speeding up the rate of a reaction.

Concentration and Reaction Rate

A higher concentration means more effective collisions where the reactants meet the minimum energy required, increasing the reaction rate.

Surface Area and Reaction Rate

Increased surface area exposes more particles to the reaction, allowing for a greater chance of effective collisions and a faster reaction rate.

Temperature and Reaction Rate

Higher temperatures cause particles to move faster, resulting in a greater chance for effective collisions and a faster reaction rate.

Activation Energy (Ea)

The minimum energy required for reactant particles to turn into product.

Catalyst in Reaction

A catalyst lowers the activation energy of a reaction, providing an alternate pathway which speeds up the reaction.

Inhibitor

A substance that slows down or prevents a chemical reaction.

Exothermic Reaction

A reaction that releases energy, resulting in the products having lower energy than the reactants (negative ΔH).

Endothermic Reaction

A reaction that absorbs energy, resulting in the products having higher energy than the reactants (positive ΔH).

Rate Determining Step

The slowest step in a multi-step reaction, which determines the overall rate of the reaction.

Bond Energy and Reaction Type

Bond breaking requires energy (endothermic), while bond formation releases energy (exothermic). The overall energy change determines whether a reaction is exothermic or endothermic.

Arrhenius Equation

A mathematical expression that shows the relationship between the rate constant, temperature, activation energy, and frequency factor of a chemical reaction: k = Ae^{-\frac{E_a}{RT}}, where: k is the rate constant, A is the frequency factor, E_a is the activation energy, R is the ideal gas constant, T is the absolute temperature (in Kelvin).

Heterogeneous Catalyst

Provide a surface for the reaction. Involve

Homogeneous Catalyst

A catalyst in the same phase as the reactants.

A temporary