howfast.2 Flashcards
How does a catalyst work?
Catalysts lower the activation energy by providing an alternative reaction pathway, allowing more successful collisions and speeding up the reaction.
What do catalysts do and not do?
Catalysts speed up reactions but are not used up in the process.
What is the meaning of a reversible reaction?
A reaction that can go in both directions (reactants ⇌ products).
What is the collision theory?
For a reaction to occur, reactant particles must collide with enough energy.
Give 2 ways to measure the rate of a reaction.
Amount of reactant used up (divided by time) or amount of product formed (divided by time).
What is the effect of temperature on rates?
Higher temperatures make particles move faster, increasing the rate of collisions and reaction speed.
What effect does a catalyst have on the rate of reaction?
Catalysts lower the activation energy, allowing more successful collisions and speeding up the reaction.
What effect does surface area have on the rate of a reaction?
A larger surface area exposes more particles, increasing collisions and speeding up the reaction.
What is the effect of concentration/pressure on the rate of reaction?
Higher concentration (solutions) or pressure (gases) increases particle collisions, speeding up the reaction.
What is the mass of a substance measured with?
A balance.
Volume of a gas is measured with?
A gas syringe or burette.
What factors affect rates of a reaction?
Temperature, concentration, pressure, surface area, and catalysts.
What is activation energy?
The minimum energy required for particles to react.
What does an iron catalyst do?
It helps in the production of ammonia from nitrogen and hydrogen.
What’s a platinum catalyst effect?
It also aids in the production of ammonia from nitrogen and hydrogen.
What is bond breaking?
An endothermic process where energy is needed to break bonds.
What is bond formation?
An exothermic process where energy is released when new bonds are formed.
How can you calculate the overall energy change for a reaction?
Using bond energies (Energy of bond breaking - Energy of bond making).
What happens if activation energy is low?
Reactions can occur more easily since particles don’t need much energy to react.
What is the position of equilibrium?
When the forward and reverse reactions happen at the same rate, and the amounts of reactants and products remain constant.
What is Le Chatelier’s Principle?
If a dynamic equilibrium is disturbed, the system shifts to counteract the change.
How does changing concentration affect equilibrium?
Adding more reactant shifts the equilibrium to make more product.
How does temperature affect equilibrium?
Increasing temperature shifts the equilibrium towards the endothermic reaction, while decreasing it shifts towards the exothermic side.
How does changing pressure affect equilibrium?
Increasing pressure shifts the equilibrium to the side with fewer molecules.
What happens if you add a catalyst to an equilibrium reaction?
It speeds up the rate at which equilibrium is reached but does not affect the position of equilibrium.
Why do particles need to collide with each other?
So bonds can break and new substances can form.
Why are powders like icing sugar or flour dangerous?
They have a large surface area, which increases the reaction rate, making them highly flammable.
What are the advantages of using catalysts?
They can be used in small amounts repeatedly, saving costs in industrial processes.
What is a drawback of catalysts?
Catalysts are specific to the reactions they catalyze and may not work for all reactions.
What are catalysts in living things called?
Enzymes (biological catalysts).
Where do reactions stop?
When one or both reactants are used up.
What is the limiting reactant?
The reactant that is completely consumed in a reaction, stopping the reaction from proceeding further.
How can the rate of reaction between marble chips and hydrochloric acid be changed?
By altering the temperature or surface area of the marble chips.
How do you measure the rate of reaction on a graph?
Draw a tangent at the point of interest and calculate the gradient (change in volume of gas divided by time).
