21 Questions
What is formed between a reactant and a catalyst, according to the intermediate complex theory?
An unstable intermediate
What is the term for the accumulation of one substance at the surface of another?
Adsorption
What is the effect of fine division or porosity of the catalyst on the reaction rate?
The reaction rate increases
What are substances that block active sites on the catalyst, thereby reducing the reaction rate?
Catalytic poisons
What is the term for a reaction in which heat is lost, as indicated by a negative ∆H?
Exothermic reaction
What is the effect of a 10K increase in temperature on the number of collisions between reactants?
A small (50%) increase
How is the instantaneous rate of reaction determined?
By drawing a tangent to the curve at a point
What is the relationship between concentration and rate, according to the experiment?
Concentration is directly proportional to rate
What is the purpose of the catalyst in a reaction, according to the surface adsorption theory?
To provide active sites for the reaction to occur
What is the definition of a catalyst, and how does it differ from the reactants in a chemical reaction?
A catalyst is a substance that alters the rate of a chemical reaction, but is chemically unchanged at the end of the reaction. It differs from the reactants in that it is not consumed or altered during the reaction.
What is the difference between heterogeneous and homogeneous catalysis?
Heterogeneous catalysis occurs when the catalyst is in a different physical phase to the reactants, whereas homogeneous catalysis occurs when the catalyst is in the same physical phase as the reactants.
What is the role of activation energy in a chemical reaction?
Activation energy is the minimum energy with which colliding particles must have for a reaction to occur.
What is the definition of an effective collision in a chemical reaction?
An effective collision is one that has sufficient activation energy and results in product being formed.
How does the concentration of reactants affect the rate of a reaction?
An increase in the concentration of reactants will increase the rate of reaction.
What is the instantaneous rate of a reaction?
The instantaneous rate of a reaction is measured as the change in concentration of any one reactant or product per unit time at one specific point.
What is the role of manganese dioxide in the decomposition of hydrogen peroxide?
Manganese dioxide acts as a catalyst, increasing the rate of the reaction.
What is the difference between autocatalysis and other types of catalysis?
Autocatalysis is a type of catalysis where a product of a reaction becomes a catalyst for the same reaction.
What is the intermediate formation theory, and how does it relate to homogeneous catalysis?
The intermediate formation theory involves homogeneous catalysis, where the catalyst forms an intermediate compound with the reactants, which then breaks down to form the products.
How does decreasing the activation energy affect the rate of reaction?
The rate of reaction is increased
How can the activation energy of a reaction be changed?
By using a catalyst
How can a catalyst lower the activation energy of a reaction?
It provides an alternative pathway(mechanism) for the reaction.
Test your understanding of rates of reaction, including the production of oxygen experiment, instantaneous rate, and factors that affect reaction rates such as concentration, temperature, particle size, and catalyst presence. Quiz yourself on the breakdown of hydrogen peroxide and more!
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