Chap 2: Kinetic Particle Theory Flashcards
What is kinetic particle theory?
All matter is made up of tiny particles in constant random motion
What are the properties of solids?
- closely packed in orderly manner
- vibrate/rotate about fixed positions
- very low kinetic energy
- strong forces of attraction, energy needed
- definite volume
- definite shape
- cannot be compressed
What are the properties of liquids?
- closely packed in disorderly manner
- slide past one another freely
- low kinetic energy
- less strong forces of attraction
- indefinite shape
- fixed volume
- cannot be compressed
What are the properties of gases?
- very far apart in disorderly manner
- move quickly and randomly in any direction
- high kinetic energy
- weak forces of attraction
- indefinite shape
- indefinite volume
- can be compressed
What is melting?
solid to liquid with thermal energy gain
What is freezing?
liquid to solid with thermal energy lost
What is condensation?
gas to liquid with thermal energy lost
What is boiling?
liquid to gas with thermal energy gain
What is evaporation?
liquid to gas (particles at liquid’s surface gain enough energy to overcome FOA and escape as vapour)
What is sublimation?
solid to gas with thermal energy gain
What is deposition?
gas to solid to thermal energy lost
Why does temperature remain constant at solid-liquid state? (heat gain)
Thermal energy absorbed which causes an increase in energy which is used to overcome FOA. Orderly arrangement is then disrupted and temperature remains constant until all ice has melted.
Hence, temperature is constant because molecules require enough thermal energy to overcome its FOA.
Why does temperature remain constant at solid-liquid state? (heat loss)
Thermal energy lost to surroundings which causes an decrease in energy which draws particles together by FOA. Particles slow down and become orderly and temperature remains constant until all ice has solidifies.
Hence, temperature is constant because molecules require enough thermal energy to attract its FOA.
Describe boiling curve.
thermal energy increases, particle energy increases, which decreases FOA. Particles move further apart, quickly and randomly which increases KE of particles
Describe cooling curve.
KE turn to thermal energy to the surroundings, which decreases the energy of the particles. FOA increases and the particles are drawn closer together, which becomes less disorderly which decreases the KE of particles
What is diffusion?
Net movement of particles from higher to lower region of concentration.
What are the factors affecting diffusion?
Temperature & Particle mass
How does temperature affect rate of diffusion?
The higher the temperature, the faster rate of diffusion.
- increase in temperature causes increase in thermal energy and KE. there will be an increase in movement of particles and rate of diffusion
How does particle mass affect rate of diffusion?
Particles with higher molecular mass move more slowly than lower Mr, hence decreasing rate of diffusion
- higher Mr, higher mass and more KE needed to move at given speed, which decreases rate of diffusion
How does gravity affect the rate of diffusion?
Gravity slows down the rate of diffusion if the substance is moving against gravity.
How to calculate molecular mass of a substance?
Add together the atomic masses from periodic table.
eg CO2 ( C = 12, O = 16)
12 + 16 + 16 = 44
