What causes ideal gas behavior to deviate?
High pressures and low temperatures leading to the importance of intermolecular interactions and nonzero particle volume.
What is the formula to track deviations from ideal gas behavior for 1 mole?
The formula is: \(n = \frac{PV}{RT}\).
Ideal gas behavior isn't observed at high pressures and/or low temperatures because _______ and the _______ of particles becomes important.
Ideal gas behavior isn't observed at high pressures and/or low temperatures because intermolecular interactions and the nonzero volume of particles becomes important.
What is the van der Waals equation for real gases?
The equation is \((P + \frac{n^2a}{V^2})(V - nb) = nRT\).
What correction does the van der Waals equation apply to pressure and volume?
It corrects for intermolecular forces and volume of gas particles.
Which of the following gases is least likely to
behave as an ideal gas at high pressures or
low temperatures?
A. He a=0.0341 L2atm/mol2 b=0.0237 L/mol
B. CO2 a=3.59 L2atm/mol2 b=0.0427 L/mol
C. CH4 a=2.25 L2atm/mol2 b=0.0428 L/mol
D. N2 a=1.39 L2atm/mol2 b=0.0391 L/mol
E. Cl2 a=6.49 L2atm/mol2 b=0.0562 L/mol
E. Cl2 a=6.49 L2atm/mol2 b=0.0562 L/mol
How would you solve for the predicted pressure for 8.0 mol Cl₂ in a 4.0 L tank at 27°C assuming ideal gas behavior? (Remember: 1 mole of ideal gas at STP is 22.4 L)
because HIGH pressure, has to use the real gas van der waals equation with a given a and b
Is 8.0 mol Cl₂ in a 4.0 L tank at 27°C behaving as an ideal gas?
No, it is not behaving ideally.
What are intramolecular forces?
Intramolecular forces are forces within a molecule, including covalent, ionic, and metallic bonds.
THESE FORCES ARE STRONG
What is the strength of intramolecular forces?
Intramolecular forces are strong, generally ranging from ~400 to 1000 kJ/mol.
What are intermolecular forces?
Intermolecular forces are weak forces that exist between two separate molecules or between molecules and ions.
What is the general strength range of intermolecular forces?
Intermolecular forces tend to be weaker, generally ranging from ~1 to 150 kJ/mol.
What physical properties are controlled by intermolecular forces?
Intramolecular forces include _______, _______, and _______ bonds.
Intramolecular forces include covalent, ionic, and metallic bonds.
What indicates the strength of intermolecular interactions in a substance?
The boiling or melting point of the substance.
What does a higher boiling point indicate about intermolecular interactions?
It indicates stronger intermolecular interactions.
The boiling point of a substance indicates the strength of the _______ between its molecules.
The boiling point of a substance indicates the strength of the intermolecular interactions between its molecules.
Higher boiling/melting point = _______ intermolecular interactions.
Higher boiling/melting point = stronger intermolecular interactions.
What are the five types of intermolecular forces?
What do all intermolecular interactions involve?
They are all electrostatic interactions (attraction of +/- regions).
How does the strength of intermolecular forces correlate with the amount of charge?
More +/− regions lead to a stronger interaction.
What are dispersion forces?
Momentary shift in electron density (electrons move to one side of molecule)
What phenomenon leads to a temporary dipole?
There is an uneven distribution of electrons (electrons move from one side to another) which leads to temporary separation of charge in an atom/molecule
This is part of London dispersion forces
What factors affect polarizability?
Relative ease of electron cloud distortion, more electrons= bigger electron cloud and more distortion to induce a temporary dipole!!!
London dispersion forces increase with size due to polarizibility
What forces are always present in all molecules?
Dispersion forces are always present in all molecules.
What are the only intermolecular forces possible for nonpolar molecules?
The only intermolecular forces possible for nonpolar molecules are London dispersion forces.
Factors affecting the strength of dispersion forces include: - _______ of atoms/molecules - _______ of molecules.
Factors affecting the strength of dispersion forces include: - size of atoms/molecules - shape of molecules.
Larger atoms/molecules are more polarizable than smaller atoms/molecules due to a larger _______. This leads to a larger _______ and larger _______.
Larger atoms/molecules are more polarizable than smaller atoms/molecules due to a larger electron cloud. This leads to a larger induced dipole and larger dispersion forces.
Which hydrocarbon is predicted to have the highest boiling point?
a) Methane, CH4
b) Ethane, C2H6
c) Propane, C3H8
d) Butane, C4H10
e) Pentane, C5H12
e) Pentane (C₅H₁₂)
What is the relationship between molecular size and boiling point?
Increase in size leads to increase in polarizability, which increases dispersion forces.
What is the boiling point trend of hydrocarbons in relation to molar mass?
Boiling point increases with molar mass due to enhanced intermolecular interactions.
How does shape, specifically surface area, affect strength of London dispersion forces?
Linear molecules have higher polarizability (greater dispersion forces) than branched molecules of similar MW (think about how non-branched molecules can stack more closely and have stronger forces)
To determine if a molecule is polar, check for an _______ of charge.
To determine if a molecule is polar, check for an asymmetric distribution of charge.
When visualizing the molecule in 3D, you should determine its _______.
When visualizing the molecule in 3D, you should determine its electron and molecular geometry.
Look for a net dipole by checking for _______, lone pairs, and formal charge.
Look for a net dipole by checking for unbalanced polar bonds, lone pairs, and formal charge.
Which of the following molecules is polar?
a) ClF3
b) CCl4
c) XeF4
a) ClF3
The Lewis structure can be drawn by considering the following aspects: - Think about the molecule in 3D - Look for net dipole - Identify _______, _______, and _______.
The Lewis structure can be drawn by considering the following aspects: - Think about the molecule in 3D - Look for net dipole - Identify unbalanced polar bonds, lone pairs, and formal charge.
What is the interaction between a polar molecule and a nonpolar molecule called?
Dipole-induced dipole interaction
Which 2 molecules are an example of a polar molecule and nonpolar molecule that have dipole induced dipole?
H2O and O2
The interaction between a polar molecule (e.g., H₂O) and a nonpolar molecule (e.g., O₂) is called a _______.
The interaction between a polar molecule (e.g., H₂O) and a nonpolar molecule (e.g., O₂) is called a dipole-induced dipole interaction.
What is the role of water in the dipole-induced dipole interaction?
It acts as a polar molecule.
What type of interaction does H₂O demonstrate with O₂?
Dipole-induced dipole interaction
How does temperature affect the solubility of O₂ in water?
The solubility of O₂ decreases with an increase in temperature.
Global warming could lead to fish suffocation due to decreased oxygen. This is because the solubility of O₂ decreases with an increase in _______.
Global warming could lead to fish suffocation due to decreased oxygen. This is because the solubility of O₂ decreases with an increase in temperature.
What happens to fish if global warming continues?
Fish may suffocate due to decreased O₂ solubility.
What happens to O₂ solubility with increasing temperature?
O₂ solubility in water decreases with increasing temperature.
What type of interaction occurs between polar molecules?
Dipole-Dipole interaction
In a dipole-dipole interaction, the +/- ends of polar molecules _______ while the +/+ or -/- ends _______.
In a dipole-dipole interaction, the +/- ends of polar molecules attract while the +/+ or -/- ends repel.
The interaction between polar molecules involves attraction of the _______ and _______ ends.
The interaction between polar molecules involves attraction of the partial positive and partial negative ends.
What do the δ- and δ+ symbols represent in dipole interactions?
They represent partial negative and positive charges, respectively.
What is a hydrogen bond?
It is the strongest dipole-dipole interaction occurring between H (covalently bonded to N, O, or F) and another N, O, or F atom in a different molecule.
The hydrogen bond occurs due to the electronegativity of _______, _______, and _______ making H very positive in the bond H-F, H-O, or H-N.
The hydrogen bond occurs due to the electronegativity of N, O, and F making H very positive in the bond H-F, H-O, or H-N.
Why do hydrogen bonds occur with H bonded to N, O, or F?
The small size of N, O, and F allows for a closer approach of the second molecule, enhancing the bond.
What is the role of electronegativity in hydrogen bonds?
High electronegativity of N, O, and F leads to a strong positive charge on H, enhancing the bond's strength.
Hydrogen bonding occurs between an H and an atom of _______, _______, or _______ in another molecule.
Hydrogen bonding occurs between an H and an atom of N, O, or F in another molecule.
Which pure liquid may exhibit hydrogen bonding
between its own molecules?
a) BCl3
b) H2
c) HF
d) CH4
e) None of these
c) HF
H-bonding leads to exceptionally strong _______.
H-bonding leads to exceptionally strong intermolecular interactions.
What is a significant effect of H-bonding on boiling points?
It leads to unusually high boiling points.
What is the interaction between ions (charged molecule) and polar molecules called?
Ion-dipole interaction
Which part of the dipole do cations attract?
Which part of the dipole do anions attract?
Cation-dipole attractions involve cations being attracted to the _______ end of the dipole.
Cation-dipole attractions involve cations being attracted to the negative end of the dipole.
Anion-dipole attractions involve anions being attracted to the _______ end of the dipole.
Anion-dipole attractions involve anions being attracted to the positive end of the dipole.
What factors determine the strength of ion-dipole interactions?
Q1Q2/d
Metal salts (like NaCl) dissolve in water due to _______.
Metal salts (like NaCl) dissolve in water due to ion-dipole interactions.
What happens to cations and anions when salt dissolves in water?
i.e NaCl in water
What is formed when water surrounds ions in a solution?
A 'sphere of hydration' for ions and a 'sphere of solvation' for other molecules.
What are the components shown in the water molecule diagram?
How do ionic interactions compare to covalent bonds?
Ionic interactions have ~same energy as covalent bonds.
The strongest intermolecular forces are the interactions _______ aka _______.They lead to solids with high melting temperatures.
The strongest intermolecular forces are the interactions ions aka ion-ion interactions.They lead to solids with high melting temperatures.
Ionic interactions are the strongest intermolecular forces, similar in energy to _______.
Ionic interactions are the strongest intermolecular forces, similar in energy to covalent bonds.
Dispersion forces can be stronger than _______ forces with _______.
Dispersion forces can be stronger than dipole-dipole forces with large molecules.
All interactions are electrostatic, with stronger interactions due to _______ regions.
All interactions are electrostatic, with stronger interactions due to more +/- regions.
What kind of forces are all interactions categorized as?
Electrostatic interactions.
Rank the molecular interactions by strength?
What causes ideal gas behavior to deviate?
High pressures and low temperatures leading to the importance of intermolecular interactions and nonzero particle volume.
What is the formula to track deviations from ideal gas behavior for 1 mole?
The formula is: \(n = \frac{PV}{RT}\).
Ideal gas behavior isn't observed at high pressures and/or low temperatures because intermolecular interactions and the nonzero volume of particles becomes important.
What is the van der Waals equation for real gases?
The equation is \((P + \frac{n^2a}{V^2})(V - nb) = nRT\).
What correction does the van der Waals equation apply to pressure and volume?
It corrects for intermolecular forces and volume of gas particles.
Which of the following gases is least likely to
behave as an ideal gas at high pressures or
low temperatures?
A. He a=0.0341 L2atm/mol2 b=0.0237 L/mol
B. CO2 a=3.59 L2atm/mol2 b=0.0427 L/mol
C. CH4 a=2.25 L2atm/mol2 b=0.0428 L/mol
D. N2 a=1.39 L2atm/mol2 b=0.0391 L/mol
E. Cl2 a=6.49 L2atm/mol2 b=0.0562 L/mol
E. Cl2 a=6.49 L2atm/mol2 b=0.0562 L/mol
How would you solve for the predicted pressure for 8.0 mol Cl₂ in a 4.0 L tank at 27°C assuming ideal gas behavior? (Remember: 1 mole of ideal gas at STP is 22.4 L)
because HIGH pressure, has to use the real gas van der waals equation with a given a and b
What are intramolecular forces?
Intramolecular forces are forces within a molecule, including covalent, ionic, and metallic bonds.
THESE FORCES ARE STRONG
What is the strength of intramolecular forces?
Intramolecular forces are strong, generally ranging from ~400 to 1000 kJ/mol.
What are intermolecular forces?
Intermolecular forces are weak forces that exist between two separate molecules or between molecules and ions.
What is the general strength range of intermolecular forces?
Intermolecular forces tend to be weaker, generally ranging from ~1 to 150 kJ/mol.
What physical properties are controlled by intermolecular forces?
What indicates the strength of intermolecular interactions in a substance?
The boiling or melting point of the substance.
What does a higher boiling point indicate about intermolecular interactions?
It indicates stronger intermolecular interactions.
The boiling point of a substance indicates the strength of the intermolecular interactions between its molecules.
What are the five types of intermolecular forces?
What do all intermolecular interactions involve?
They are all electrostatic interactions (attraction of +/- regions).
How does the strength of intermolecular forces correlate with the amount of charge?
More +/− regions lead to a stronger interaction.
What are dispersion forces?
Momentary shift in electron density (electrons move to one side of molecule)
What phenomenon leads to a temporary dipole?
There is an uneven distribution of electrons (electrons move from one side to another) which leads to temporary separation of charge in an atom/molecule
This is part of London dispersion forces
What factors affect polarizability?
Relative ease of electron cloud distortion, more electrons= bigger electron cloud and more distortion to induce a temporary dipole!!!
London dispersion forces increase with size due to polarizibility
What forces are always present in all molecules?
Dispersion forces are always present in all molecules.
What are the only intermolecular forces possible for nonpolar molecules?
The only intermolecular forces possible for nonpolar molecules are London dispersion forces.
Factors affecting the strength of dispersion forces include: - size of atoms/molecules - shape of molecules.
Larger atoms/molecules are more polarizable than smaller atoms/molecules due to a larger electron cloud. This leads to a larger induced dipole and larger dispersion forces.
Which hydrocarbon is predicted to have the highest boiling point?
a) Methane, CH4
b) Ethane, C2H6
c) Propane, C3H8
d) Butane, C4H10
e) Pentane, C5H12
e) Pentane (C₅H₁₂)
What is the relationship between molecular size and boiling point?
Increase in size leads to increase in polarizability, which increases dispersion forces.
What is the boiling point trend of hydrocarbons in relation to molar mass?
Boiling point increases with molar mass due to enhanced intermolecular interactions.
How does shape, specifically surface area, affect strength of London dispersion forces?
Linear molecules have higher polarizability (greater dispersion forces) than branched molecules of similar MW (think about how non-branched molecules can stack more closely and have stronger forces)
The Lewis structure can be drawn by considering the following aspects: - Think about the molecule in 3D - Look for net dipole - Identify unbalanced polar bonds, lone pairs, and formal charge.
What is the interaction between a polar molecule and a nonpolar molecule called?
Dipole-induced dipole interaction
Which 2 molecules are an example of a polar molecule and nonpolar molecule that have dipole induced dipole?
H2O and O2
The interaction between a polar molecule (e.g., H₂O) and a nonpolar molecule (e.g., O₂) is called a dipole-induced dipole interaction.
How does temperature affect the solubility of O₂ in water?
The solubility of O₂ decreases with an increase in temperature.
Global warming could lead to fish suffocation due to decreased oxygen. This is because the solubility of O₂ decreases with an increase in temperature.
What happens to fish if global warming continues?
Fish may suffocate due to decreased O₂ solubility.
What happens to O₂ solubility with increasing temperature?
O₂ solubility in water decreases with increasing temperature.
In a dipole-dipole interaction, the +/- ends of polar molecules attract while the +/+ or -/- ends repel.
The interaction between polar molecules involves attraction of the partial positive and partial negative ends.
What do the δ- and δ+ symbols represent in dipole interactions?
They represent partial negative and positive charges, respectively.
What is a hydrogen bond?
It is the strongest dipole-dipole interaction occurring between H (covalently bonded to N, O, or F) and another N, O, or F atom in a different molecule.
The hydrogen bond occurs due to the electronegativity of N, O, and F making H very positive in the bond H-F, H-O, or H-N.
Why do hydrogen bonds occur with H bonded to N, O, or F?
The small size of N, O, and F allows for a closer approach of the second molecule, enhancing the bond.
What is the role of electronegativity in hydrogen bonds?
High electronegativity of N, O, and F leads to a strong positive charge on H, enhancing the bond's strength.
Which pure liquid may exhibit hydrogen bonding
between its own molecules?
a) BCl3
b) H2
c) HF
d) CH4
e) None of these
c) HF
What is a significant effect of H-bonding on boiling points?
It leads to unusually high boiling points.
What is the interaction between ions (charged molecule) and polar molecules called?
Ion-dipole interaction
What factors determine the strength of ion-dipole interactions?
Q1Q2/d
What happens to cations and anions when salt dissolves in water?
i.e NaCl in water
What is formed when water surrounds ions in a solution?
A 'sphere of hydration' for ions and a 'sphere of solvation' for other molecules.
What are the components shown in the water molecule diagram?
How do ionic interactions compare to covalent bonds?
Ionic interactions have ~same energy as covalent bonds.
The strongest intermolecular forces are the interactions ions aka ion-ion interactions.They lead to solids with high melting temperatures.
Rank the molecular interactions by strength?
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