Chapter 02 - Kinetic Particle Theory Flashcards
Matter takes up ____ and has ____
Matter takes up space and has mass
Matter can exist in ____, ____ & ____ states
Matter can exist in solid, liquid & gaseous states
What are the 2 laws that kinetic particle theory states?
1) Matter is made up of tiny particles which can be atoms, ions or molecules
2) The particles have kinetic energy and hence are in constant and random motion
What is the movement of particles in a solid?
Particles vibrate at fixed positions
What is the movement of particles in a liquid?
Move about within the confined space and slide past each other
What is the movement of particles in a gas?
Move freely in all directions at a high speed
Describe the attractive forces of particles in a solid
Very strong
Describe the attractive forces of particles in a liquid
Moderate
Describe the attractive forces of particles in a gas
Very weak
Describe the arrangement of particles in a solid
Orderly arranged
Describe the arrangement of particles in a liquid
Disorderly arranged
Describe the arrangement of particles in a gas
Disorderly arranged
Describe the distance of particles in a solid
Very closely packed
Describe the distance of particles in a liquid
Closely packed
Describe the distance of particles in a gas
Very far apart
What are the 3 properties of solids?
1) Fixed volume and shape (arranged in fixed position + regular pattern, SAF prevents particles from breaking away from their positions)
2) Not compressible (closely packed together, little spaces to squeeze them)
3) Not able to flow (particles only vibrate about fixed positions)
What are the 4 properties of liquids?
1) Fixed volume and no fixed shape (moderate forces of attraction prevents particles from escaping their positions)
2) Able to flow easily (move about, slide past each other within confined space)
3) Not compressible (closely arranged, less space between particles)
4) Takes up shape of container (move about within confined space)
What are the 4 properties of gases?
1) No fixed volume and shape (move freely and randomly, forces of attraction can’t hold them in confined space)
2) Compressible (far apart, more space between)
3) Flow easily (move freely at high speed)
4) Takes up shape and volume of container (move freely in all directions to occupy every corner)
A change in the physical state does not produce any new substances. True or false?
True, it’s just called physical change
When a substance undergoes changes in the physical states, ____ ____ is either given out/taken in from the surroundings
When a substance undergoes changes in the physical states, thermal energy is either given out/taken in from the surroundings
When thermal energy is given out to the surroundings, what is it called?
Exothermic
When thermal energy is taken in from the surroundings, what is it called?
Endothermic
Changes in state typically take place at random temperatures of a PURE substance. True of false?
False, changes in states typically take place at specific melting and boiling points of pure substances
What does thermal energy do to attractive forces?
Thermal energy is involved in breaking down the attractive forces or the formation of attraction
State the definition of melting, the energy changes (endo/exothermic) taking place and why
Melting is a process where a solid changes into a liquid
Endothermic - to overcome attractive forces between particles
State the definition of boiling, the energy changes (endo/exothermic) taking place and why
Boiling is a process where a liquid changes into a gas
Endothermic - to overcome attractive forces between particles
State the definition of sublimation, the energy changes (endo/exothermic) taking place and why
Sublimation is a process where a solid changes into a gas directly
Endothermic - to overcome attractive forces between particles
State the definition of condensation, the energy changes (endo/exothermic) taking place and why
Condensation is a process where a gas changes into a liquid
Exothermic - to allow formation of attractive forces between particles
State the definition of freezing, the energy changes (endo/exothermic) taking place and why
Freezing is a process where a liquid changes into a solid
Exothermic - to allow formation of attractive forces between particles
State the definition of deposition, the energy changes (endo/exothermic) taking place and why
Deposition is a process where a gas changes into a solid without becoming a liquid
Exothermic - to allow formation of attractive forces between particles
When temperature increases/decreases, does thermal energy affect the average kinetic energy of particles?
Yes
(Before changing in state) When the average kinetic energy of particles ____, temperature ____
(Before changing in state) When the average kinetic energy of particles increases, temperature increases (vice versa)
(During changing in state)
Why does temperature remain constant and how does it affect the average kinetic energy of particles
(During changing in state)
Temperature remains constant because thermal energy is used to break/form forces of attraction between particles, thermal energy has no effect on the average kinetic energy of particles at this point
What are the 3 transition temperatures?
Melting, boiling, freezing points - substances change in state at these temperatures and not change in temperature
What is evaporation, what energy change takes place (endo/exothermic) and how is it different from the other processes?
Evaporation is a process where a liquid changes into a gas
Endothermic
Different because it takes place at the surface of a liquid in contact with air at any temperature below its boiling point
Describe what happens from A to B (Heating curve) when a solid is heated to its melting point
1) From A to B, thermal energy is absorbed from the surroundings increasing the kinetic energy of the particles
2) Vibrations become more vigorous and faster at their fixed positions
3) Causes temperature to increase
Describe what happens from B to C (Heating curve) when there is a mixture of solid and liquid at the melting point
1) At B, temperature reaches the melting point and the increased energy of particles overcomes the attractive forces between them in solid state
2) Melting takes place an the particles start to break free from their fixed positions and become disorderly arranged
3) Temperature remains the same during melting as the thermal energy taken in is used to break the attractive forces between the particles, so the average kinetic energy stays the same
4) During melting, the substance exists as a solid-liquid mixture
Describe what happens from C to D (Heating curve) when a liquid is heated to its boiling point
1) At C, the solid substance melts completely and particles slide past each other freely and are disorderly arranged
2) Thermal energy taken in from the surroundings causes kinetic energy of the liquid particles to increasing, causing them to move around more vigorously
3) Temperature of the liquid increases from its melting point
Describe what happens from D to E (Heating curve) when there is a mixture of liquid and gas at the boiling point
1) At D, temperature reaches boiling point and the increased energy of particles overcomes the attractive forces between them in liquid state
2) Boiling occurs and the particles move in all random directions
3) The temperature remains constant because all thermal energy taken in is used to break the attractive force between the particles, so the average kinetic energy stays the same
4) Substance exists as a liquid-gas mixture
Describe what happens from A to B (cooling curve) when the temperature of a gas is lowered to the point of condensation
1) From A to B, the kinetic energy of gas particle decreases when they lose thermal energy to the surroundings, moving less vigorously
2) Temperature of the solid decreases
Describe what happens from E to F (Heating curve) when a gas is heated
1) At E, the liquid substance boils off completely and the particles move freely in all directions
2) Thermal energy taken in from the surroundings causes the kinetic energy of particles to increase, so they move around more vigorously
3) Temperature of gas increases beyond the boiling point
Describe what happens from B to C (cooling curve) when there is a mixture of liquid and gas at the condensation point
1) At B, the temperature decreases to the condensation point, the moderate attractive forces between the particles start to form
2) The particles move closer and become less disorderly arranged and condensation occurs
3) Temperature remains constant because thermal energy loss to the surroundings is compensated by the thermal energy given out during formation of attractive forces
4) Substance exists as a gas-liquid mixture
Describe what happens from C to D (cooling curve) when the temperature of a liquid is lowered to the point of freezing
1) At C, the gas substance condenses completely and liquid particles can move about freely within confined spaces
2) The kinetic energy of the liquid particles decrease when their thermal energy is lost to the surroundings, so they move less vigorously
3) Temperature decreases
Describe what happens from D to E (cooling curve) when there is a mixture of solid and liquid at the freezing point
1) At D, the temperature drops to the freezing point, and the strong attractive forces between particles start to form
2) Particles become closely packed and orderly arranged and vibrate at their fixed positions, freezing takes place
3) Temperature remains the same because thermal energy lost to the surroundings is compensated by the thermal energy given out during formation of attractive forces between the particles, average kinetic energy of particles stay the same
4) Substance exists as a liquid-solid mixture
Describe what happens from E to F (Cooling curve) when the temperature of a solid is lowered
1) At E, the liquid substance is completely solidified, the solid particles have regular fixed arrangement and vibrate at their fixed positions
2) Kinetic energy of the solid particles decrease when they lose their thermal energy to the surroundings
3) Temperature decreases below freezing point
When does sublimation take place?
When particles of a solid substance is heated and absorb thermal energy from the surroundings to overcome strong forces of attraction between them
What is the result of the SAF being overcome in sublimation?
The particles change from vibrating about fixed positions to moving freely and randomly in all directions, and the solid changes into a gas directly
Does the temperature remain constant during sublimation?
Yes, the temperature remains constant until a solid changes into a gas completely
What is the opposite of sublimation?
Deposition
What is deposition?
Deposition is when a substance changes from a gas to a solid directly
When does deposition occur?
Deposition occurs when particles of a vapour are cooled and lose thermal energy to the surroundings, allowing strong forces of attraction between them to form
What is the result of the SAF forming?
Particles change from moving freely and randomly in all directions to vibrating about fixed positions, so gas changes into a solid directly
What is sublimate?
Sublimate is the solid substance formed by cooling its vapours
Why do small gaps exist between railway tracks?
To provide space for expansion and contraction on hot and cold days respectively
How do small gaps between railway tracks help during hot days?
1) Average kinetic energy of the solid particles increases when they absorb thermal energy from surroundings
2) Particles vibrate more vigorously about their fixed positions causes the spaces to become slightly wider
3) Gaps allow track to expand so that they don’t expand sideways and cause trains to derail
How do small gaps between railway tracks help during cold days?
1) On cold days, the average kinetic energy of solid particles decreases when they lose their thermal energy to the surroundings
2) Particles vibrate less vigorously about their fixed positions causing them to come closer than before
3) Gaps allow the track to contract so that the track will not be damaged
How are gases modified to be transported more efficiently?
As liquids occupy less space than gases, liquid particles only move about within confined spaces while gas moves around freely in all directions. Therefore, oxygen and nitrogen gases are liquefied before being transported reducing the amount of storage tanks and truck deliveries to transport these gases
What is diffusion?
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient
What does diffusion of substances in liquid and gases show about particles?
Particles are in constant, random movement
What are the 2 factors that affect the rate of diffusion?
Molecular mass and temperature
What is molecular mass?
Molecular mass is the total mass of all atoms in a substance
How does molecular mass affect the rate of diffusion?
The larger the molecular mass, the slower the rate of diffusion (Vice versa)
Calculate the molecular mass of CO2
44 (g/mol)
How does temperature affect rate of diffusion?
1) As temperature affects kinetic energy of particles, it can affect rate of diffusion
2) As temperature rises, more energy is supplied to the particles of the substance and the kinetic energy of the particles increase moving faster in all directions. Hence, rate of diffusion increases
3) As temperature decreases, less energy is supplied to the particles of the substance and the kinetic energy of particles decrease moving slower. Hence, rate of diffusion decreases
