Module 3 reaction rates Flashcards
What is the equation used to calculate rate?
Rate= change in concentration/ time
What is the unit for rate of reaction?
mol dm-3 s-1
What must particles do in order to react?
Collide with enough energy(activation energy) and the correct orientation.
Factors that affect rate of reaction?
- Temperature
- Pressure
- Concentration
- Surface area
- Catalyst
What is the effect on the rate of reaction from rising the temperature?
Increase in rate of reaction due to a much higher proportion of particles having energy greater than the activation energy , meaning many more successful collision per second ultimately increasing the rate.
Effect of increasing concntration/pressure?
Increases the rate of reaction by, there being more particles in a given voluem maening more frequent collisions increasing the rate.
What are the variables monitored in an experiment for the rate of reaction?
- Concentration of reactant or product.
- Gas volume of products
- Mass of substances formed
How would you calculate the rate from a concentration time graph?
Drawing a tangent, then workout the gradient of the tangent using the equation;
Gradient= change in y/ change in x
What is a catalyst?
A substance which increases the rate of reaction but is not used up itself in the reaction.
How does a catalyst work and how does it increase the rate of reaction?
Catalysts provide an alternate reaction pathway (with a lower activation energy).
Due to the lower activation energy, more particles have energy > activation, so more frequent successful collisions, so increased reaction rate.
What does homogenous catalyst mean?
A catalyst that is in the same phase as the reactants.
What does heterogeneous catalyst mean?
Catalyst used in the reaction is in different phase to the reactants.
What is activation energy?
The minimum energy that particles must collide with for a reaction to occur.
What are the axis in a Boltzmann distribution?
X- axis is the energy and the Y- axis is the number of molecules with a given energy.
