Ch.5 Phases and phase changes Flashcards
Which phase is said to have a fixed shape and volume, and particles do not flow past each other?
Solid
What are the two types of solids?
Amorphous - not ordered, strong material
Crystalline - Ordered structure, contains a repeating pattern. (there are 4 types of crystalline solids)
What are the crystalline solids?
Ionic solids
Molecular - molecules that are not ionic
Covalent network - molecules that contain covalent bonds
Metallic - contains delocalized electrons
Which phase is said to have no fixed shape but does have a fixed volume?
Liquids
The resistance of a liquid to flow is known as
Viscosity
What is surface tension?
amount of energy needed to increase the surface area of a liquid
The attraction of molecules between 2 different substances is known as?
Adhesive force
What is capillary action?
Movement of a liquid up the side of a narrow tube, against gravity
Which phase is said to have no fixed shape or any volume?
Gas
The generic formula of pressure is?
force/area
A standard unit of gas is?
Paschal (N/meter squared)
Which phase transition is fusion?
A solid goes to a liquid form (melting)
Which phase transition is Freezing?
liquid to a solid
Which phase transition is VAporization?
liquid to a gas
Which phase transition is condensation?
gas to a liquid
Which phase transition is sublimation
Solid to a gas
Which phase transition is Deposition
gas to a solid
Which form of energy determines if phases change?
Thermodynamics (ΔG)
To go from a solid to a liquid, how would this affect ΔG
Heat is required to melt something, this would mean the ΔH would be positive (Endothermic) and ΔS would be positive as this is a favorable reaction.
The overall ΔG would be positive and form a spontaneous reaction.
What is the Enthalpy of fusion (ΔHf)?
how much heat is needed to melt 1 mol of substance.
The unit is given in kJ/mol (Q=mΔHf)
Where is the mass of water/substance
What is Heat of vaporization (ΔHvap)?
The heat required to vaporize 1 mol of substance.
The phase of a substance depends on what two factors?
Temp and pressure
What is the difference between triple point and critical point?
The triple point is where all 3 passes are at equilibrium
critical point is the terminal point of liquid gas
What is supercritical fluid?
A substance that has qualities of both gas (low viscosity) and liquid (higher density)
The average kinetic energy of a gas is proportional to?
temperature of the gas
What is the ideal gas behavior?
High temp make substances more gas-like
Lots of volume and little pressure make favorable behavior
When dealing with gas, what should the unit for temp be?
Kelivin
C + 273
What is boyle’s law?
Pressure and volume are inversely related.
p1 V1 = p2 V2
What is Charles’s law?
Volume and temp of a gas are directly related
V1/T1 = V2/T2) & (V1/T1 = K
What is Avagadro’s LAw?
Volume of gas is directly related to the number of mol of gas particle
(V1/n1 = V2/n2) & (V/n = K)
What are the standard molar volume units for gas?
STP = 1 atm and 0°C (273K)
1 mole = 22.4L
What is the formula for the IDeal gas law?
PV = nRT R = Ideal gas constant R = 0.08L atm/mol K R = 8.31 J/mol K
How do real gases compare to ideal?
Real gas particles do have size may exhibit molecular forces (Interforces) Real gas equations use the Vander Waals equation (P + a/Vm squared) (Vm - b) = RT V-b = volume taken up by gas P + a/Vm - Vm - molar volume a - attractive intermolecular forces b - size of particles
In regard to the Vander Waals equation, a polar molecule will exhibit a
larger “A” term, and behave less ideal-like (compared to non-polar)
What is Dalton’s law?
The total pressure of the mixture of gasses equas the sum of the partial pressures of individual gasses.
The pressure from a gas is independent of other gasses but depends solely on the total pressure and mole fraction of said gas.
How do you calculate mole fraction?
Xgas = ngas/ntotal
xgas = Pgas/Ptotal
What is Graham’s Law?
Smaller lighter particles diffuse faster than larger ones
Movement of particles can be described as what type of energy?
Kinetic
What is the KE equation?
KE = 1/2mV squared
What is a solution?
homogeneous mixture
(T/F) solutions can exist in any phase.
True
(T/F) Solutions can only be formed from one phase.
False.
Can be formed from components of different phases
What is Dissolution?
When a solute interacts with a solvent (disolve).
What is the difference between a solute and a solvent?
A solute is the minority part. It is typically solid.
A solvent is the majority component and breaks particles into ions.
With respect to solutions, what does the term like dissolves like mean?
Polar solutes dissolve in polar solvents
non-polar in non-polar
When does precipitation occur in a solution?
After saturation has reached the maximum
What are the units to describe saturation?
g/L
What two factors affect solubility?
Temp and pressure
Gas is more soluble in liquids at which temp? Why?
lower temp.
Due to the kinetic energy, high temp = high KE for gas
Which molecules are always soluble?
alkali earth metals
and Nitrate, Chlorate, Acetate
Which molecules are sometimes soluble?
Halides unless within Ag, Pb, Hg
Sulfate unless with Ca, Sr, Ba, Pb
Which molecules are always insoluble?
CO3^2-
PO4^3-
S^-2
SO3^2-
Which molecules are sometimes insoluble?
Hydroxides and metal oxides - unless present with Ca, Sr, Ba
Concentration is measured in what 3 ways?
Molarity
Molality
Normality
What is Molarity?
Molarity (M) - equals moles of solute/liter of solution (mol/L)
What is molality?
molality (m) - moles of solute/kilogram of solvent (mol/kg)
- In low concentrations of solute volume isn’t effected much so 1kg = 1L
What is Normality (N)?
equivalents/liter of solution
-used in acid/base reactions
How do you calculate normality?
N(acid) = molarity of acid x acidic protons per molecule
N(base) = Mbase (mol/L) x hydroxide ions per molecule
What is the solubility equilibrium?
Ksp = Products/reactants
solids and liquids not included
What would a high Ksp value mean?
high solubility
What would a low Ksp value mean?
Insoluble
How do you calculate molar solubility?
Ksp = [cation][Anion]
What is the common Ion effect?
The solubility of an ionic species decreases when one of its component ions is already present in a solution
