Final Exam Flashcards
What tells you a molecule has ionic bonding as an intermolecular force?
Has ions, not polar
What tells you a molecule has ion-dipole forces as an intermolecular force?
Has ions involved, is polar
What tells you a molecule has hydrogen bonding as an intermolecular force?
NO ions involved, IS polar, has hydrogen bonded to N, O, or F atoms
What tells you a molecule has dipole-dipole forces as an intermolecular force?
No ions involed, IS polar, does NOT have hydrogen bonded to N, O, or F atoms
What tells you a molecule has london dispersion forces as an intermolecular force?
No ions involved, no polar molecules involved
What are the oxidation rules for alkali metals and alkaline earth metals in compounds?
Alkali metal=+1
Alkaline Earth=+2
IN A COMPOUND, not alone
What is the rule for the oxidation number of hydrogen in compounds?
It is +1, except it is -1 when combined with metals or boron in binary compounds
What is the oxidation rule with halogens?
-1, except when combined with a halogen above them on the periodic table or with oxygen
What is the oxidation rule for oxygen?
-2, except it’s -1 in peroxides
Explain the relationship between effective nuclear charge, atom size, and the shielding effect.
Effective nuclear charge causes the overall attraction an electron experiences. Electrons between the nucleus and atom being considered lessens, or shields the atom from full nuclear charge. More electron shells=larger atom
What is the trend with atom size in the periodic table and why?
Increases going from top to bottom in a group because of an increasing number of electron cells
Decreases going from left to right because of an increasing number of protons, meaning more attraction
What is ionization energy? What needs to be overcome to remove an electron?
The energy needed to completely remove an electron from an atom. Energy must overcome the attraction between the nucleus and electron.
What factors effect the magnitude of ionization energy and why? What does it contribute to the trend of ionization energy?
- Size of the atom-the closer the electron is to the nucleus, the harder it is to remove. Ionization energy decreases from top to bottom, since valence electrons get further from nucleus
- Effective nuclear charge-Greater effective nuclear charge means it’s harder to remove. Ionization increases from left to right since effective nuclear energies do
What is electron affinity and its trend?
Electron affinity is the energy change that results from adding an electron to an ion or atom. It increases from left to right owing to increased effective nuclear charge, and decreases from top to bottom within a group owing to increased size
How are ionic and covalent bonds different physically? (3)
- Ionic bonds have higher melting points than covalent bonds
- Ionic bonds have higher electrical conductivity than covalent bonds
- Covalent bonds have shared electrons
What is an electrolyte?
A substance that when dissolved in water produces a solution that can conduct an electric current.
Which types of electrolytes conduct electricity effectively and ineffectively?
Strong electrolytes conduct electricity very efficiently
Weak electrolytes conduct only a small current
Nonelectrolytes conduct no current at all
When are ionic substances good and bad conductors? Why?
Conduct well when melted, poorly when solid. When melted, the crystal lattice is broken and ions can move
What happens if you add or remove something from an equation?(Lechateliers)
Add: Shift away from the side where the addition occurred
Remove: shift towards removal
What is Le Chatelier’s rules with pressure/volume
If pressure increases/volume decreases, rxn will shift to the side with the fewest moles to relieve stress
What does a positive, negative, and 0 value of 🔼G* indicate?
🔼G<0: Spontaneous in forward reaction
🔼G>0: Not spontaneous in forward direction
🔼G=0: System is at equilibrium
What do positive and negative values of 🔼S tell us?
🔼S>0: disorder increases
🔼S<0: disorder decreases
What do negative and positive 🔼H values represent?
🔼H>0: Reaction absorbed heat, it is endothermic
🔼H<0: Reaction released heat, it is exothermic
What is molality?
The number of moles of solute per kilogram of solvent
