Matter Flashcards
Gases, Properties of Solutions, Concentration & Solubility, Properties of Solids, Intermolecular Forces & Phase Changes
What is The Kinetic Theory of Matter?
all gas molecules, regardless of size, are in constant motion
some have more kinetic energy than others, but none will be static at any given point in time
gives rise to many gases intrinsic properties
Name and briefly describe the 5 intrinsic properties of gases
low density - a lot of space between molecules, expand to fill space
pressure exertion - constant motion = collisions = pressure on container wall
diffusibility - mix gases evenly
no definitive shape - expand to occupy whatever space they’re in
compressibility - vast space between molecules allows gas expansion and compression
What is the “Ideal Gas Law”?
a way of bringing together the different aspects of a gas, relating temperature, pressure, volume and the molar quantity of a gas
limitation - assumes the gas is an ideal gas
uses- in reality, a gas will have a lot of different properties and the notion of an ideal gas describes a model with which a real gas can be examined in
What are the main properties of an ideal gas?
gas molecules do not attract or repel each other
the volume of one individual gas molecule is negligible
no energy gained or lost through elastic collisons
What is the “Ideal Gas Law” equation?
PV = nRT
P = pressure (Pa)
V = volume (m3)
n = moles of gas
R = ideal gas constant (8.31 J/K mol)
T = temperature (Kelvin)
What is the difference between a “solute” & “solvent”
solute - a small component that dissolves in a given solution
solvent - a large component in which the solute is dissolved in
What are the 4 colligative properties of a solution?
vapour pressure - the likelihood of any particular solution evaporating/ forming a vapour at a given temperature
osmotic pressure - the pressure required to prevent osmotic flow towards the solution
boiling point
freezing point
What are the consequences when you increase the concentration of a solute in a solution?
increase in boiling point
decrease in freezing point
decrease in vapour pressure
What occurs when you increase the boiling point of a solution?
freezing point decreases - particles are impeding this process of bonding
vapour pressure decreases - solution boils less readily
State and briefly describe the 4 key factors that affect solubility
Pressure - gases may become more soluble when pressure increases, liquid and solids unaffected
Temperature - solutes may become more soluble when temperature increase
Polarity - like solutes and solvents will easily dissolve
Molecular Size - larger particles or molecules as solutes are less soluble
Define “Concentration”
the amount of solute in a particular volume of solvent
n/V = C
n = number of moles - Mass/molar mass
V = volume (L)
C = concentration (M or mol/L)
What are the properties of “Ionic Solids”?
Texture - hard and brittle
Melting point - high
Conductivity - poor conductors when solid but when aqueous is a good conductor
What are the properties of “Molecular Solids”?
Texture - soft due to weak forces
Melting Point - low due to weak forces
Conductivity - unable to conduct electricity as electrons remain within the respective molecules
only exists at sufficiently low temps
What are the properties of “Metallic Solids”?
Texture - shiny and malleable
Melting Point - high due to sea of delocalised electrons
Conductivity - great conductors of heat and electricity
What are the properties of “Covalent Network Solids” with examples?
3D covalent network solids are extremely hard - e.g Diamonds
2D covalent network solids are soft, as the bonds between layers are weak intermolecular forces - e.g Graphite
What is the difference between intra and inter-molecular forces?
Intra - strong attraction that binds together atoms in a compound/molecule
Inter - weaker attraction between molecules
What is the difference between polar and non-polar molecules?
Polar molecules - constant fixed dipole moment e.g molecules with highly electronegative element
Non-polar molecules - do not have a fixed charge, but can still have temporary, transient dipole moments e.g hydrocarbons and symmetrical molecules with highly electronegative elements
What are the 3 main intermolecular forces?
London/ Dispersion Forces
Dipole-Dipole Attractions
Hydrogen Bonds
What are London/Dispersion Forces?
primary force in non-polar molecules and hydrocarbons where temporary and transitionary dipole moments form between molecules
strength of forces increases with the size of the molecule as the number of transitionary dipole moments increase
What are Dipole-Dipole attractions?
dipole moment - the differences in charge between the atoms in molecules, based on their differences in electronegativity
the fixed d+/d- of a dipole moment in one polar molecule is attracted via electrostatic charge to the fixed d+/d- dipole moment in another polar molecule creating an intermolecular force
What is hydrogen bonding?
occurs in polar molecules that contain a constant, fixed dipole moment between a highly electronegative atom (F/O/N) and hydrogen
What is a phase change, and what are the phase changes of matter?
reversible movements from one state to another caused by changes in spatial relationship
What physical conditions affect the spatial relationship in phase change?
Temperature - breaks weak intermolecular forces between molecules
Pressure - increasing pressure will make a system more ordered
