Solids
The particles in a solid are said to have ____ positions.
Fixed
Describe the effect of intermolecular forces on the vapor pressure of a liquid
As the intermolecular forces increases, the vapor pressure will decrease.
What does the kinetic theory say about the size of a gas particle?
Extremely small in size (occupy negligible or insignificant volume)
Temperature & Pressure
Explain the relationship between the Kelvin temperature of a substance and the kinetic energy of its particles
The Kelvin temperature is directly proportional to the average kinetic energy of the particles in the substance. Ex: If temperature doubles, KE doubles
Describe what condition is necessary in order for a solid to melt. Your answer has to include IM forces
The particles in a solid must be able to overcome the intermolecular forces of attraction.
What is evaporation?
The conversion of a liquid to a gas below the boiling point of the substance.
What does the kinetic theory say about the speed and movement of a gas particle?
Gas particles move very fast. The particles move in a ‘random walk’ type fashion (move until collide with something, then change directions).
What is the triple point?
The conditions of temperature and pressure at which all three states of matter are in equilibrium with each other (S, L, G, exist simultaneously).
What is significant about the temperature absolute zero?
This is the temperature at which all particle motion stops (the particles have no kinetic energy).
Explain why solid magnesium chloride (MgCl2) has a higher melting point than solid sucrose
(C12H22O11).
Ionic solids have much stronger attractive forces between the ions than the molecules solids. Therefore, more energy is needed to make the ionic solid melt.
Why is evaporation a cooling process?
The particles with the greatest kinetic energy leave the liquid, leaving the slower moving (low kinetic energy) particles behind. (Similar to taking out the fastest runner in a race – it leaves the slower runners behind.)
What does the kinetic theory say about the collisions of gas particles?
Collisions are said to be ‘elastic’ which means that energy is never lost upon collision, just that it is transferred.
What processes occur on the line between the liquid and gas phase?
Evaporation & Condensation
How can you raise the average kinetic energy of the water molecules in a glass of water?
Heating up the glass of water
What must be true for sublimation to occur?
Vapor Pressure > atm Pressure
Explain the difference in the evaporation of a contained liquid and an uncontained liquid
The particles with a cap (the contained liquid) cannot escape. This represents a dynamic equilibrium where particles are evaporating and condensing at the same rate. The particles without a cap will diffuse out of the container through evaporation.
What are the 3 values of standard pressure? You must get all three to receive points
1 atm
101.3 kPa
760 mmHg
What processes occur on the line between the solid and gas phase?
Sublimation and Deposition
What is dynamic equilibrium?
When 2 opposite processes occur at the same rate and it looks like nothing is happening but the reaction is still occuring.
What are the two types of solids? The answer is not ionic and molecular.
Crystalline and Amorphous
What is the difference between the B.P. and n.B.P. of a liquid?
The normal boiling point can only be observed at sea level. Boiling point is observed at other altitudes besides sea level.
How could you increase the pressure of a sample of gas particles? You must get all three to receive points
Increase temperature
decrease volume occupied by the gas
increase amount of gas
If the melting/freezing line is slanted to the right what does that mean?
The solid is more dense than the liquid state.
Would you expect an equilibrium vapor pressure to be reached above a liquid in an open container? Why or why not?
No equilibrium will not be reached because without the lid, the particles will diffuse out of the container. The rate of evaporation will be greater than the rate of condensation.