Particles and Rate of Reaction (TOPIC 13) Flashcards
What are the characteristics of a solid?
Strong forces of attraction between particles hold them close together in fixed positions where they vibrate around a fixed point.
What are the characteristics of a liquid?
Weak force of attraction between particles.
Random arrangement flow around and over each other.
Definite volume not shape
Expand slightly when heated
What are the characteristics of gases?
Very weak forces of attraction free to move far apart
Constantly move in random directions in straight lines
No definite shape or volume
When heated they expand or pressure increases
Solid to liquid?
Melting
Solid to gas?
Sublimation
Gas to liquid?
Condensing
Liquid to solid?
Freezing
Liquid to gas?
Evaporation
Describe what happens to the particles in the solid when they get heated.
Gain energy, heat to kinetic
Vibrate quicker
This weakens the forces that hold them together
Then at a certain temp called melting point the particles have enough energy to break free from their positions
What is diffusion?
Movement of particles from an area of high concentration to low concentration.
How do reactions happen?
When particles collide with enough energy they react. When particles collide with greater to or equal to the activation energy it is a successful collision
What factors affect rate of reaction?
Concentration
Catalyst
Temperature
Surface area/particle size
How does the concentration affect rate of reaction?
More particles in a fixed volume means more frequent collision so there will be more chance of successful collisions
How does the temperature affect rate of reaction?
Higher temperature means more kinetic energy in the particles so there is more frequent collisions with higher energy. More successful collisions.
How does the Surface Area affect rate of reaction?
Increase in surface area means a larger SA to Volume ration allows more collisions at the surface.
How does a catalyst affect the rate of reactions?
Increases the rate of reaction by offering an alternative energy pathway with a lower activation energy.
Therefore more particles have the energy required for a successful collision.
What is catalyst?
A substance that increases the rate of reaction by offering an alternative pathway with lower activation energy.
Is not used up at the end of the reaction.
Investigate the effect of changing the surface area of calcium carbonate chips on the rate of reaction.
Using an air tight concical flask with a bung on top attached to a gas syringe.
Add 20cm3 of dilute HCl to the conical flask. Weigh out 2g of CaCO3 add to the conical flask. Measure the volume of CO2 gas produced from the reaction in the gas syringe.
Repeat using the same mass of Chips and volume and concentration of acid but different size of chip.
Investigate the effect on the catalytic decomposition of hydrogen peroxide solution
Add hydrogen peroxide into a conical flask
Use a delivery tube to connect this flask to a measuring cylinder upside down in water trough
Add the chosen catalyst into the conical flask and close the bung
Measure the volume of gas produced in a fixed time using the measuring cylinder - the volume of water displaced
Repeat experiment with different solids and compare results
