LO 11 - 21 Flashcards
Equation to calculate energy added to increase heat
q = m ⋅ Cs ⋅ Δ T
- m is mass
- Cs is specific heat
Equation to calculate energy added to change state
q = n ΔH (state change)
- n is mols
- either ΔH fusion, vaporization
You can tell what state is denser on a phase diagram based on the …
lean of the fusion curve; the state the curve leans TOWARDS is less dense
What are the three sub-groups of crystalline solids?
Molecular, ionic, and atomic
Solid with molecules as the composite units held together by the associated IMFS?
Molecular solids
Molecular solids have ____ melting points
low
Solid with ions as the units that are held together by strong coulombic bonds?
Ionic solids
Ionic solids have ____ melting points
high
Solid composed of individual atoms?
Atomic solids
_________ atomic solids are held together by weak LDF and pack tightly to maximize interactions?
Nonbonding
________ atomic solids are held together by metallic bonds contributing to the e sea
Metallic
_______ _________ atomic solids are held together by covalent bonds in geometric structures
Network Covalent
Nonbonding AS have ___ melting points
Metallic AS have ____ melting points
Network Covalent AS have ___ melting points
low, variable, high
What are allotropes
forms of the same element in different arrangements. i.e. graphite or diamond
Long chains-like molecules composed of repeating monomers
Polymers
Monomer A + Monomer B = _______
Dimer
Condensation polymers ______ atoms or small groups during polymerization
eliminate
Addition polymers _____ _______ without elimination
link together
The amount of a substance that will dissolve in a given amount of solvent
solubility
solvent-solute > = solvent-solvent AND solute-solute interactions
solution generally forms
solvent-solute < solvent-solvent and solute-solute interactions
solution may or may not form
When two substances are soluble in each other in all proportions they are _____
miscible
The energy to separate solute particles (ΔH solute) and solvent particles (ΔH solvent) from each other is always ______
endothermic, ΔH > 0
Mixing the solute and solvent (ΔH mix) is an _________ process
exothermic, ΔH < 0
What is Hess’s Law
The enthalpy change of solution is the sum of its formation steps:
ΔH solution = ΔH solute + ΔH solvent + ΔH mix
For ionic compounds dissolved in water, ΔH solvent and ΔH mix are combined into one term called _______
heat of hydration (ΔH hydration)
heat of hydration is always ______
exothermic
For ionic compounds, ΔH solute = ______
-ΔH lattice
Soulutions reach dynamic equilibrium when ______
rates of dissolution = recrystallization
_________ solutions have dynamic equilibrium between dissolved and undissolved solute
saturated
A solution containing less solute than equilibrium is _______
unsaturated
A highly unstable solution containing more solute than equilibrium is ______
supersaturated
The solubility of solids in water
______ with increasing temperature
↑ increases
The solubility of gasses in water
____ with increasing temperature
____ with increasing pressure
↓ decreases
↑ increases
Henry’s Law
Solubility gas = Kh ⋅ P gas
- Kh is a constant
- P gas = P total ⋅ mol fraction gas
Properties that depend on the number of particles dissolved in solution
colligative properties
The VP of a nonvolatile nonelectrolyte + solvent is ____ the VP of pure solvent
less than
Raoult’s Law for the VP of a solution
P solution = X solvent ⋅ P solvent ( ⋅ i)
- X mol fraction
- VP pure solvent
- Van Hoff factor if electrolyte
What is Raoult’s Law for two gasses?
P total = Pa + Pb
Pa = Xa ⋅ P pure a
Pb = Xb ⋅ P pure b
Strong solute-solvent interactions in gasses cause a _______ deviation from Raoult’s Law
negative
Weak solute-solvent interactions in gasses cause a _______ deviation from Raoult’s Law
positive
The freezing point of a solution containing a nonvolatile solute is ____ than the freezing point of pure solvent
lower
Equation for freezing point depression
ΔTf = m ⋅ Kf
- ΔTf change in C relative to pure solvent
- m is molality
- Kf constant for solvent
The boiling point of a solution containing a nonvolatile solute is _____ than the boiling point of pure solvent
higher
Equation for boiling point elevation
ΔTb = m ⋅ Kb
- ΔTb change in C relative to pure solvent
- m is molality
- Kb constant for solvent
The pressure needed to stop osmotic flow
osmotic pressure
Equation for osmotic pressure
Π = M ⋅ R ⋅ T
- Π is osmotic pressure
- M is molarity
- R gas constant = 0.08206
- T in Kelvin
