Rate of reaction Flashcards
How can the rate of a reaction be measured?
Rate = amount of product formed/time
or
Rate = amount of reactant used/time
What is required for a successful collision?
Particles must have at least the activation energy
Why does increasing temperature increase rate of reaction?
Increasing the temperature increases the speed of the reacting particles so that they collide more frequently and more energetically.
Why does increasing pressure increase rate of reaction?
Increasing the pressure of reacting gases means there are more particles in a given volumes. This increases the frequency of collisions and so increases the rate of reaction.
Why does increasing concentration increase rate of reaction?
Increasing the concentration of reactants means there are more particles in a given volume. This increases the frequency of collisions and so increases the rate of reaction.
Why does increasing surface area increase rate of reaction?
Increasing the surface area of solid reactants means more particles are exposed. This increases the frequency of collisions and so increases the rate of reaction.
What is a catalyst?
Catalysts change the rate of chemical reactions but are not used up during the reaction.
Why are catalysts important in industrial processes?
They speed up reactions, and allow lower temperatures and pressures to be used. This reduces costs
How could you record data to show the rate of a reaction?
Use a mass balance to measure mass of product lost over time.
Use a gas syringe or measuring cylinder to capture gas produced over time.
Observing how long it takes for a solution to go opaque over time.
Which factors affect the rate of a reaction?
Temperature Concentration Surface Area Presence of Catalyst Pressure (gases only)
A reaction produced 15cm3 of gas in 10 seconds. What is the rate of reaction?
1.5cm3 per second
What is the activation energy of a reaction?
The minimum amount of energy required for a particle to have a successful collision
Why is a catalyst more effective in pellets rather than as a whole lump?
Greater surface area means more of the catalyst is exposed, so there are more successful collisions and therefore reaction rate increases.
