liquids and solids - mrs. freeman's ap chemistry
TRANSCRIPT
Chapter 10 Notes.notebookNov 151:29 PM
Types of Solids Crystalline solids: Solids with highly regular arrangement of their components
Amorphous solids: Solids with considerable disorder in their structures.
Chapter 10 Notes.notebook
Nov 151:54 PM
Lattice: A 3D system of points designating the positions of the components (atoms, ions or molecules) that make up the substance
Unit Cell: The smallest repeating unit of the lattice structure.
XRay Diffraction: The method is to determine the structure of a crystalline solid. Diffraction patterns of light are measured and compared
Types of Solids
Nov 152:02 PM
Molecular Solids have discrete and relatively small molecules at the lattice points that are held together by IMFs
Examples: ice, dry ice, and sugars.
Types of Solids: Molecular solids
Properties: low melting/boiling points, poor conductors, low densities, typically soft.
Chapter 10 Notes.notebook
Dec 28:44 AM
Ionic Solids have ions at the lattice points and held together by strong electrostatic attractions (stronger than traditional IMF's). Examples: Sodium chloride and lithium nitrate
Types of Solids: Ionic solids
Properties Include: High melting/boiling points, brittle (due to cleavage), poor conductors as solids, good conductors as liquids or in solutions, high densities.
Dec 28:44 AM
Types of Solids: Network Solids Atomic/Molecular Network Solids: atoms/compounds at the lattice points and held together by directional covalent bonds (stronger than IMF and electrostatic)
Examples: graphite, diamond, and quartz (SiO2).
Chapter 10 Notes.notebook
Nov 152:11 PM
Closet Packing: A metallic crystal structure where the atoms are spherical and packed together and bonded to each other equally in all directions
Metals are held together by nondirectional covalent bonds where the electrons are delocalized throughout the structure (weaker than directional covalent bonds)
Types of Solids: Metallic Solids
Properties: High melting/boiling points, good conductors, high densities, malleable/ductile.
Nov 152:25 PM
Alloy: A substance that contains a mixture of elements and has metallic properties Substitutional Alloy: Some of the host metal atoms are replaced by other metal atoms of similar size (Sterling Silver93% silver 7% copper, Pewter85% tin 7% copper 6% bismuth and 2% antimony)
Interstitial Alloy: When some of the interstices (Holes) in the closet packed metal structure are occupied by small atoms (Steel contains carbon atoms in the holes of an iron crystal)
Types of Solids: Metallic Solids
Chapter 10 Notes.notebook
Lack of rigidity (ability to flow) (viscosity and surface tension)
High Density (compared to gases)
Nov 277:20 AM
Vaporization (Evaporation): Molecules of a liquid escape the liquid's surface and form a gas
Condensation: Vapor molecules reform a liquid
Equilibrium: Two opposite processes exactly balanced with each other
Vapor pressure: The pressure of the vapor present at equilibrium
Liquids
L + G Gas
Heat Curve: A plot of temperature versus time for a process where energy is added at a constant rate
Endothermic: Reactions require (take in) energy (heat)
Exothermic: Reactions release (give off) energy (Heat) Breaking bonds is ALWAYS Endothermic
Normal Melting Point: The temperature at which the solid and liquid states have the same vapor pressure under conditions where the total pressure is 1 atm Normal Boiling Point: The temperature at which the vapor pressure of the liquid is exactly 1 atm
Nov 267:48 AM
Heat of vaporization (Enthalpy of vaporization): The energy required to vaporize 1 mole of a liquid at a pressure of 1 atm.
Heat of Fusion (Enthalpy of fusion): The change in energy that occurs at the melting point when a solid melts
Phase Change
Specific Heat Capacity: The energy required to raise the temperature of one gram of a substance by one degree Celsius
q = (m)(C)ΔT q = energy (Joules or KJ) m = Mass (grams) C = Specific Heat Capacity ΔT = Change in temperature
Chapter 10 Notes.notebook
Phase Change
CIce = 2.087 J/g ΔHFus = 6.02 KJ/mol CWater = 4.184 J/g ΔHVap = 40.7 KJ/mol CSteam = 1.996 J/g
How many kilojoules are needed to raise the temperature of 112g of ice at 18.0 to steam at 109?
Nov 283:58 PM
Phase Change Phase Diagrams: A diagram that represents the phases of a substance as a function of temperature and pressure (This is in a CLOSED system)
Triple Point: The point in which all states of matter exist Critical Point: The point where the critical pressure meets the critical temperature. After this point there is only a "intermediate fluid" that is neither vapor nor liquid
Chapter 10 Notes.notebook
Phase Change Phase Diagram Fun Facts:
A liquid boils at the temperature with the vapor pressure of the liquid equals the external pressure.
This is why it takes longer to hard boil an egg in the mountains than it does at the ocean. Water will boil at a lower temperature where there is less pressure (mountains) meaning the egg has to cook longer to hard boil in the lower temperature.
Nov 275:46 PM
Chapter 10 Notes.notebook
Properties of Solutions Solution: Homogeneous mixture where a solute is dissolved in a solvent
Dilute: Relatively little solute present
Concentrated: Large amount of solute present
Nov 275:46 PM
Properties of Solutions Ways to Express Concentration:
Molarity: Moles divided by Liters (Mol/L which is symbolized by M)
Mass Percent (Weight Percent): The percent by mass of the solute in the solution
Mole Fraction: The ratio of moles of a given component to the total number of moles
Molality: Moles of solute per kilogram of solvent symbolized by a m
Chapter 10 Notes.notebook
Nov 275:46 PM
Properties of Solutions Steps of the Formation of a Liquid Solution
1). Separating the solute into its individual components (expanding the solute)
2). Over coming intermolecular forces in the solvent to make room for the solute (expanding the solvent)
3). Allowing the solute and solvent to interact to form the solution
Steps 1 and 2 are commonly endothermic Step 3 is commonly exothermic
Think about the intermolecular forces!!!
Nov 275:46 PM
Nov 275:46 PM
Properties of Solutions Enthalpy of Solution (ΔHsoln): The change in energy associated with the formation of the solution. It is the sum of the energy changes for all three steps.
ΔHsoln = ΔH1 + ΔH2 + ΔH3 If ΔH has a positive sign the step was endothermic (energy absorbed) if ΔH has a negative sign the step was exothermic (energy was released)
Nov 275:46 PM
Properties of Solutions Enthalpy of Solution (ΔHsoln):
ΔHsoln = ΔH1 + ΔH2 + ΔH3 Let's look at dissolving oil in water:
Step 1: Expansion of the solute medium +ΔH Oil is a nonpolar substance that only has LDF holding it together. These intermolecular forces are weak and only require a small amount of energy to break apart, however since oil is a larger compound it will take more energy to "untangle" the molecules from each other
Step 2: Expansion of the solvent large +ΔH Water has very strong intermolecular forces (Hydrogen bonds) that will require a lot of energy to separate the molecules. This will result in a large amount of energy
Step 3: solute and solvent interaction small ΔH The interaction between water (polar) and oil (nonpolar) will be negligible causing a very small release of energy
The medium and large positive step 1 and step 2 and the very small negative step 3, cause the overall process to be very large and positive. This means this solution will unlikely not occur. (Enthalpy is not the ONLY determining factor!!!)
Chapter 10 Notes.notebook
Properties of Solutions
Enthalpy of Hydration (ΔHhyd): Combines the energy of step 2 and step 3 due to the fact that hydration is the process in which water separates from itself and surrounds the ions present in solution.
NaCl(s) ⇒ Na+(g) + Cl(g) ΔH1 = 786 kJ/mol
H2O(l) + Na+(g) + Cl(g) ⇒ Na+(aq) + Cl(aq) ΔH2+3 (ΔHhyd) = 783 kJ/mol
ΔHsoln = 786 kJ/mol 783 kJ/mol = 3 kJ/mol The overall reaction is positive, but it still occurs quite readily. This is due to the fact that enthalpy is not the only factor when determining whether a process will proceed readily. Entropy (chaos) is also taken into consideration.
Let's look at dissolving salt in water:
Nov 275:46 PM
Polar solute, Polar solvent
Nonpoar solute, Polar solvent
Nonpolar solute, nonpolar solvent
Large
Small
Small
Large
Large
Large
Small
Small
Nov 275:46 PM
Factors Affecting Solubility Pressure effect: Pressure does not effect solids and liquids but does significantly effect gases.
Chapter 10 Notes.notebook
Types of Solids Crystalline solids: Solids with highly regular arrangement of their components
Amorphous solids: Solids with considerable disorder in their structures.
Chapter 10 Notes.notebook
Nov 151:54 PM
Lattice: A 3D system of points designating the positions of the components (atoms, ions or molecules) that make up the substance
Unit Cell: The smallest repeating unit of the lattice structure.
XRay Diffraction: The method is to determine the structure of a crystalline solid. Diffraction patterns of light are measured and compared
Types of Solids
Nov 152:02 PM
Molecular Solids have discrete and relatively small molecules at the lattice points that are held together by IMFs
Examples: ice, dry ice, and sugars.
Types of Solids: Molecular solids
Properties: low melting/boiling points, poor conductors, low densities, typically soft.
Chapter 10 Notes.notebook
Dec 28:44 AM
Ionic Solids have ions at the lattice points and held together by strong electrostatic attractions (stronger than traditional IMF's). Examples: Sodium chloride and lithium nitrate
Types of Solids: Ionic solids
Properties Include: High melting/boiling points, brittle (due to cleavage), poor conductors as solids, good conductors as liquids or in solutions, high densities.
Dec 28:44 AM
Types of Solids: Network Solids Atomic/Molecular Network Solids: atoms/compounds at the lattice points and held together by directional covalent bonds (stronger than IMF and electrostatic)
Examples: graphite, diamond, and quartz (SiO2).
Chapter 10 Notes.notebook
Nov 152:11 PM
Closet Packing: A metallic crystal structure where the atoms are spherical and packed together and bonded to each other equally in all directions
Metals are held together by nondirectional covalent bonds where the electrons are delocalized throughout the structure (weaker than directional covalent bonds)
Types of Solids: Metallic Solids
Properties: High melting/boiling points, good conductors, high densities, malleable/ductile.
Nov 152:25 PM
Alloy: A substance that contains a mixture of elements and has metallic properties Substitutional Alloy: Some of the host metal atoms are replaced by other metal atoms of similar size (Sterling Silver93% silver 7% copper, Pewter85% tin 7% copper 6% bismuth and 2% antimony)
Interstitial Alloy: When some of the interstices (Holes) in the closet packed metal structure are occupied by small atoms (Steel contains carbon atoms in the holes of an iron crystal)
Types of Solids: Metallic Solids
Chapter 10 Notes.notebook
Lack of rigidity (ability to flow) (viscosity and surface tension)
High Density (compared to gases)
Nov 277:20 AM
Vaporization (Evaporation): Molecules of a liquid escape the liquid's surface and form a gas
Condensation: Vapor molecules reform a liquid
Equilibrium: Two opposite processes exactly balanced with each other
Vapor pressure: The pressure of the vapor present at equilibrium
Liquids
L + G Gas
Heat Curve: A plot of temperature versus time for a process where energy is added at a constant rate
Endothermic: Reactions require (take in) energy (heat)
Exothermic: Reactions release (give off) energy (Heat) Breaking bonds is ALWAYS Endothermic
Normal Melting Point: The temperature at which the solid and liquid states have the same vapor pressure under conditions where the total pressure is 1 atm Normal Boiling Point: The temperature at which the vapor pressure of the liquid is exactly 1 atm
Nov 267:48 AM
Heat of vaporization (Enthalpy of vaporization): The energy required to vaporize 1 mole of a liquid at a pressure of 1 atm.
Heat of Fusion (Enthalpy of fusion): The change in energy that occurs at the melting point when a solid melts
Phase Change
Specific Heat Capacity: The energy required to raise the temperature of one gram of a substance by one degree Celsius
q = (m)(C)ΔT q = energy (Joules or KJ) m = Mass (grams) C = Specific Heat Capacity ΔT = Change in temperature
Chapter 10 Notes.notebook
Phase Change
CIce = 2.087 J/g ΔHFus = 6.02 KJ/mol CWater = 4.184 J/g ΔHVap = 40.7 KJ/mol CSteam = 1.996 J/g
How many kilojoules are needed to raise the temperature of 112g of ice at 18.0 to steam at 109?
Nov 283:58 PM
Phase Change Phase Diagrams: A diagram that represents the phases of a substance as a function of temperature and pressure (This is in a CLOSED system)
Triple Point: The point in which all states of matter exist Critical Point: The point where the critical pressure meets the critical temperature. After this point there is only a "intermediate fluid" that is neither vapor nor liquid
Chapter 10 Notes.notebook
Phase Change Phase Diagram Fun Facts:
A liquid boils at the temperature with the vapor pressure of the liquid equals the external pressure.
This is why it takes longer to hard boil an egg in the mountains than it does at the ocean. Water will boil at a lower temperature where there is less pressure (mountains) meaning the egg has to cook longer to hard boil in the lower temperature.
Nov 275:46 PM
Chapter 10 Notes.notebook
Properties of Solutions Solution: Homogeneous mixture where a solute is dissolved in a solvent
Dilute: Relatively little solute present
Concentrated: Large amount of solute present
Nov 275:46 PM
Properties of Solutions Ways to Express Concentration:
Molarity: Moles divided by Liters (Mol/L which is symbolized by M)
Mass Percent (Weight Percent): The percent by mass of the solute in the solution
Mole Fraction: The ratio of moles of a given component to the total number of moles
Molality: Moles of solute per kilogram of solvent symbolized by a m
Chapter 10 Notes.notebook
Nov 275:46 PM
Properties of Solutions Steps of the Formation of a Liquid Solution
1). Separating the solute into its individual components (expanding the solute)
2). Over coming intermolecular forces in the solvent to make room for the solute (expanding the solvent)
3). Allowing the solute and solvent to interact to form the solution
Steps 1 and 2 are commonly endothermic Step 3 is commonly exothermic
Think about the intermolecular forces!!!
Nov 275:46 PM
Nov 275:46 PM
Properties of Solutions Enthalpy of Solution (ΔHsoln): The change in energy associated with the formation of the solution. It is the sum of the energy changes for all three steps.
ΔHsoln = ΔH1 + ΔH2 + ΔH3 If ΔH has a positive sign the step was endothermic (energy absorbed) if ΔH has a negative sign the step was exothermic (energy was released)
Nov 275:46 PM
Properties of Solutions Enthalpy of Solution (ΔHsoln):
ΔHsoln = ΔH1 + ΔH2 + ΔH3 Let's look at dissolving oil in water:
Step 1: Expansion of the solute medium +ΔH Oil is a nonpolar substance that only has LDF holding it together. These intermolecular forces are weak and only require a small amount of energy to break apart, however since oil is a larger compound it will take more energy to "untangle" the molecules from each other
Step 2: Expansion of the solvent large +ΔH Water has very strong intermolecular forces (Hydrogen bonds) that will require a lot of energy to separate the molecules. This will result in a large amount of energy
Step 3: solute and solvent interaction small ΔH The interaction between water (polar) and oil (nonpolar) will be negligible causing a very small release of energy
The medium and large positive step 1 and step 2 and the very small negative step 3, cause the overall process to be very large and positive. This means this solution will unlikely not occur. (Enthalpy is not the ONLY determining factor!!!)
Chapter 10 Notes.notebook
Properties of Solutions
Enthalpy of Hydration (ΔHhyd): Combines the energy of step 2 and step 3 due to the fact that hydration is the process in which water separates from itself and surrounds the ions present in solution.
NaCl(s) ⇒ Na+(g) + Cl(g) ΔH1 = 786 kJ/mol
H2O(l) + Na+(g) + Cl(g) ⇒ Na+(aq) + Cl(aq) ΔH2+3 (ΔHhyd) = 783 kJ/mol
ΔHsoln = 786 kJ/mol 783 kJ/mol = 3 kJ/mol The overall reaction is positive, but it still occurs quite readily. This is due to the fact that enthalpy is not the only factor when determining whether a process will proceed readily. Entropy (chaos) is also taken into consideration.
Let's look at dissolving salt in water:
Nov 275:46 PM
Polar solute, Polar solvent
Nonpoar solute, Polar solvent
Nonpolar solute, nonpolar solvent
Large
Small
Small
Large
Large
Large
Small
Small
Nov 275:46 PM
Factors Affecting Solubility Pressure effect: Pressure does not effect solids and liquids but does significantly effect gases.
Chapter 10 Notes.notebook