Ch - 8 (Rates of Reaction) Flashcards
What are the factors that affect the rate of reaction?
- Concentration of reactant in solution
- Pressure of reacting gases.
- Temperature
- Surface area of solid reactant
- Use of catalyst
What is one use of the rate?
Economic Interest
On a graph, of increased concentration or pressure, how will u determine the line with more concentration?
- Steeper line - Higher concentration
- Less steeper line - Less concentration.
On a graph, of surface area, how will u determine the line with more surface area?
- Steeper line - More surface area (powder)
- less steeper line - Less surface area (lumps)
On a graph, on temp, how will u determine the line with more temp?
- Steeper Line - Higher temp.
- Less steeper line - Lower temp.
What is a catalyst?
- Speeds up the rate of reaction, without being altered or consumed itself.
What is one important thing to note about a reaction?
Mass of reactant = Mass of product
On a graph, on catalyst, how will u determine the line with a catalyst?
- Steeper line - with a catalyst
- less steeper line - without a catalyst
What does the collision theory state?
- the particles must collide with each other
- collision must have sufficient energy to cause reaction
What is activation energy?
The minimum energy that colliding particles must have.
What is it called if a collision occurs?
Successful collisions.
What does the no. of successful collisions depend on?
- No. of particles per unit volume
- Frequency of collisions
- Kinetic energy of particles
- Activation energy
How does temp affect the rate of reaction?
Increasing the temp will increase the rate of reaction.
Explain according to particle theory the effect of temp.
- More frequent collisions
- Higher proportion of particles have energy greater than the activation energy.
What is the rule of thumb for aqueous and gaseous systems?
- For every 10°C increase in temp, the rate of reaction approx doubles.
How does concentration affect the rate of reaction?
Increasing the concentration of the solution will increase the rate of reaction.
Explain according to particle theory the effect of concentration.
- More reactant particles in a given volume.
- ## More frequent and successful collisions per second.
What about the gaseous state reaction?
- Increases the pressure has same effect as the no. of particles occupy in small space
-This increases concentration
What will happen if we double the no. of collisions?
Double the no. of collisions per sec
What can we conclude from the no. Of collisions ?
No. of collisions is proportional to the no. of particles present.
How does surface area affect the rate of reaction?
Increasing the surface area of the solid will increase the rate of reaction.
Explain according to particle theory the effect of surface area.
- More surface area of particles is exposed
- Producing higher no. Of collisions per sec
What will happen if we double the surface area?
Double the no. of collisions per sec
What is a catalyst?
Catalyst is a substance which speeds up the rate of reaction without being altered or consumed in the reaction.
What principle do all catalysts work on?
- Providing a different pathway for the reaction to occur that has lower activation energy.
What is an example of a catalyst?
- Iron
- Used to catalyse the Haber Process for production of Ammonia
What are iron beads used for?
Surface area available for catalysis
What are enzymes?
Enzymes are biological catalysts that work best at specific temp. & pH
How much of the catalyst is required for a reaction to take place?
Small amounts
What shud u mention when answering questions on the effect of concentration on rate of reaction?
More particles per unit volume
How do we measure the rate of reaction?
- How quickly reactants are used up
- How quickly products are formed.
What are the most common techniques used to measure rate of reaction?
- Measuring mass loss on balance
- Measuring volume of gas produced.
- measuring colour change at the end of reaction.
