C8 Rates And Equilibrium Flashcards
What is the definition for rate of reaction?
A measure of how quickly the products are formed or how quickly the reactants are used up.
What are the units that are used in rate of reaction?
g/s , cm^3/s and mol/s
Why is there more than one unit for rate of reaction?
Because different methods use different units.
How can the surface area of a solid be increased?
The surface area of a solid can be increased by cutting the substance into small pieces, or by grinding it into a powder.
How does changing the surface area change the rate of reaction?
If the surface area of a reactant is increased:more particles are exposed. So there will be more frequent collisions and therefore, the rate of reaction increases.
Use collision theory to explain how increasing the surface area increases the rate of reaction.
Changing the surface area increases the rate of reaction because more particles are able to collide with each other. This means that there will be more frequent collisions, increasing the rate of reaction.
When can chemical reactions only occur?
Chemical reactions only occur when collisions occur with enough energy.
What is the activation energy of a reaction?
The minimum amount of energy needed for a reaction to occur.
What are the factors that affect the rate of a chemical reaction?
- Concentration
- Pressure
- Surface area of solid reactants
- Temperature
- Presence of a Catalyst
How does temperature affect the rate of reaction?
Increasing the temperature increases the rate of reaction, this is because the average kinetic energy of the molecules increases. This means that more molecules are moving faster and hitting each other with more energy causing more forceful and frequent collisions.
Use collision theory to explain how changing the temperature alters the rate of reaction.
Changing the temperature increases the number of particles with sufficient energy to overcome the activation energy because there is more kinetic energy. So the rate of reaction increases.
How does changing the concentration affect the rate of reaction?
Increasing the concentration increases the number of frequent collisions and so increases the rate of reaction.
Use collision theory to explain how changing concentration alters the rate of reaction.
By increasing the concentration of a solution, the amount of particles in the solution increases. Therefore there will be more frequent collisions.
Use collision theory to explain how increasing pressure increases the rate of reaction.
Increasing the pressure increases the number of reactant particles in a given volume. So as there is an increase of reactant particles this means that the particles are closer together, which means there are more frequent and forceful collisions. Therefore increasing the rate of reaction.
Describe how changing pressure affects the rate of reaction of a gas.
Increasing pressure increases the rate of reaction because it forces gas particles closer together, leading to more frequent and successful collisions.
What is the definition of a catalyst?
A catalyst is a substance which increases the rate of a reaction by providing the reactants with an alternative reaction pathway which is lower in activation energy, without itself being used up in the process.
Use collision theory to explain how adding a catalyst alters the rate of reaction.
A catalyst lowers the activation energy of a reaction which therefore means the rate of reaction will increase.
Describe how adding a catalyst affects the rate of reaction.
A catalyst increases the rate of a chemical reaction, as it allows an alternate lower activation energy.
Explain, with an example, the industrial use of a catalyst.
Platinum is use to manufacture nitric acid.
Justify the use of catalysts in industry and household products.
Catalysts are used in industry and household products because it makes them more economical.
What is an enzyme and how does it work?
Enzymes are proteins that act as biological catalysts, they work on the substrate on which enzymes act, forming products.
State collision theory.
Collision theory states that chemical reactions occur only when the reactant particles collide with sufficient energy to react.
