Rates of Chemical Reaction Flashcards
What is the rate of a chemical reaction?
Rate of Reaction: The rate of a chemical reaction is the speed at which reactants are converted into products. It can be expressed as the change in concentration of a reactant or product per unit time.
What is activation energy (Ea)?
Activation Energy (Ea): The minimum amount of energy required for a chemical reaction to occur. It is the energy barrier that reactants must overcome to form products.
How does temperature affect the rate of a reaction?
Effect of Temperature: Increasing the temperature generally increases the rate of a reaction because it provides more kinetic energy to the reactant molecules, leading to more frequent and effective collisions.
How does concentration/pressure affect the rate of a reaction?
Effect of Concentration/Pressure: Higher concentration (or pressure in gases) increases the rate of reaction by increasing the number of reactant particles in a given volume, leading to more frequent collisions.
How does surface area affect the rate of a reaction?
Effect of Surface Area: Increasing the surface area of a solid reactant (e.g., using powdered form instead of lumps) increases the rate of reaction by providing more area for collisions to occur.
What is the role of a catalyst in a chemical reaction?
Catalyst: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It works by lowering the activation energy (Ea), making it easier for the reaction to occur.
How does temperature affect the reaction between hydrochloric acid (HCl) and sodium thiosulfate (Na₂S₂O₃)?
Temperature Effect: Increasing the temperature speeds up the reaction between HCl and Na₂S₂O₃, resulting in a faster formation of sulfur precipitate.
How does concentration affect the reaction between hydrochloric acid (HCl) and marble (CaCO₃)?
Concentration Effect: A higher concentration of HCl leads to a faster rate of reaction with marble, producing carbon dioxide (CO₂) gas more rapidly.
How does surface area affect the reaction between marble (CaCO₃) and hydrochloric acid (HCl)?
Surface Area Effect: Finely powdered marble reacts more quickly with HCl than larger lumps, due to the increased surface area available for the reaction.
How does a catalyst affect the decomposition of hydrogen peroxide (H₂O₂)?
Catalyst Effect: Manganese dioxide (MnO₂) acts as a catalyst in the decomposition of hydrogen peroxide, significantly speeding up the release of oxygen gas (O₂) without being consumed.
What does a flat reaction rate curve indicate?
Flat Curve Indication: A flat reaction rate curve indicates that the reaction has reached completion or equilibrium, with no further significant changes in concentration over time.
How does the kinetic theory of matter relate to reaction rates?
Kinetic Theory Relation: The kinetic theory states that particles are in constant motion. The rate of a chemical reaction depends on the frequency and energy of collisions between reactant particles.
