Science Chemistry Flashcards
(17 cards)
What is the definition of rate of reaction?
The speed at which reactants are converted into products in a chemical reaction
Rate of reaction can be expressed in various units such as mol/L/s or g/s depending on the context.
How can different units measure the rate of reaction?
Units can vary based on the reactants and products involved, such as molarity, mass, or volume
Common units include mol/L/s for concentration changes or g/s for mass changes.
List some factors that can affect the rate of a chemical reaction.
- Temperature
- Concentration/Pressure
- Surface Area
- Presence of a Catalyst
How does temperature affect the rate of a reaction according to collision theory?
Higher temperature increases the kinetic energy of particles, leading to more frequent and energetic collisions
Increased energy can lead to a higher probability of overcoming activation energy.
Describe how surface area of a solid can be increased.
By breaking the solid into smaller pieces or grinding it into a powder
Increased surface area allows more particles to collide with reactants.
How does changing the surface area change the rate of reaction?
Increased surface area leads to more collisions between reactants, increasing the reaction rate
This is explained by collision theory.
How does concentration affect the rate of reaction?
Higher concentration increases the number of reactant particles in a given volume, leading to more collisions
This increased collision frequency can accelerate the reaction.
What is the activation energy of a reaction?
The minimum energy required for reactants to undergo a chemical reaction
Overcoming this energy barrier is crucial for the reaction to proceed.
What is a catalyst?
A substance that increases the rate of a reaction without being consumed in the process
Catalysts provide an alternative pathway with a lower activation energy.
How does a catalyst affect the rate of a reaction?
By lowering the activation energy, allowing more particles to successfully collide and react
This results in an increased rate of reaction.
How does changing the pressure of gaseous reactants affect the rate of reaction?
Increasing pressure compresses the gas, increasing the concentration of reactant molecules and collision frequency
This can lead to a faster reaction rate.
What is the purpose of using a graph to calculate the rate of reaction?
To visually represent the change in concentration or mass over time, allowing for rate determination
The slope of the tangent line at a specific time can indicate the rate.
Identify the dependent, independent, and control variables from a rates graph.
- Dependent variable: Rate of reaction
- Independent variable: Time
- Control variables: Temperature, concentration, surface area
Understanding these variables helps in analyzing the factors affecting reaction rates.
Fill in the blank: The __________ is the minimum energy required for a chemical reaction to occur.
[activation energy]
True or False: A catalyst is consumed in the reaction it catalyzes.
False
How does changing concentration affect the rate of reaction according to collision theory?
Higher concentration leads to more frequent collisions between reactant particles
This results in an increased likelihood of successful reactions.
Use a tangent to calculate the rate of reaction at a specific time.
The slope of the tangent line at the point of interest on the graph indicates the rate
This requires knowledge of calculus or graphical analysis.
