Organic Chem Class 1

Question 1

Angstrom

Answer 1

10^-10 m

Question 2

Limiting Agent

Answer 2

The reactant that runs out first; limits how much product the reaction can produce

Question 3

How do you determine percent composition by mass?

Answer 3

%x = MW of x/ total MW

Question 4

How to find a compound’s empirical formula?

Answer 4

1. Assume total gram weight
2. How may moles of x & y are there (# of moles = weight in grams/MW)
3. Find ratio of x & y

Question 5

Formula for concentration

Answer 5

Molarity (M) = # of moles of solute / # of L of solution

If more than one solute present…
Xs = # of moles of substance s / # of total moles in solution

Question 6

What happens as the energy levels increase?

Answer 6

• the distance from the nucleus increases
• need more energy to go to higher levels of energy
• gap between the energy levels decrease
• orbital shape is becoming more complex

Question 7

Excitation vs Relaxation

Answer 7

Excitation is a positive change & electron absorbs incoming photon

Absorption is a negative change & electron emits photon

The energy of the photon is the difference between the initial and final electron energy

Question 8

Energy of photon equation

Answer 8

E= hf = h (c/λ)

As energy increases, frequency increases too but wavelength decreases

Question 9

3 Rules for electron filling

Answer 9

1. Pauli’s Principle - describes carrying capacity of orbital
   - no 2 electrons are identical
   - limits occupancy of orbital to max of 2 e-
2. Aufbau Principle - describes how e- are added or removed from orbitals of different energy
   - electrons are added from lowest to highest energy & removed from highest to lowest energy
   - valence e- are in highest energy shell
   * although 3d electrons are higher in energy than 4s, you remove valence 4s electrons first
3. Hund’s Rule - describes how e- are added or removed from orbitals of the same energy
   - paramagnetic = at least one unpaired e-
   - diamagnetic = all e- paired

Question 10

Metalloids

Answer 10

Possess both metal & non-metal qualities

Boron, silicon, arsenic, antimony, polonium, tellurium, germanium

Question 11

Which transition metals have anamalous electron configurations?

Answer 11

Gold, silver, copper, chromium, molybdenum

Question 12

What does the valence shell configuration determine?

Answer 12

Chemical reactivity

Question 13

Periodic Trend - Acidity

Answer 13

Increases left to right & up to down

• acidity measures compounds ability to lower pH by donating protons or accepting e-
• acidity depends on stability of acid & its conjugate base
• the bigger the anion = the more stable acid = more acidic

Question 14

Shielding

Answer 14

Valence e- experience an electrostatic attraction due to nucleus given by: Fe ∝ Zeff = C / r^2

Question 15

Effective Nuclear Charge

Answer 15

Nuclear charge experienced by valence e- given by: Zeff = Z - core e-

Question 16

Periodic Trend - Atomic Radius

Answer 16

Increases right to left and up to down

- Fe increases and as it increases e- are pulled closer together

Question 17

Periodic Trend - Ionic Radius

Answer 17

Valence e- repulsion is slightly MORE in anions vs neutral & valence e- repulsion is slightly LESS in cations vs neutral atoms

Question 18

Periodic Trend - Ionization energy

Answer 18

Minimum amount of energy required to remove outer most e- from atom

IE increases from bottom to top & left to right

Question 19

Periodic Trend - Multiple ionization

Answer 19

Elements with closed-shell & closed-subshell configuration tend to require more energy to remove an additional electron

Question 20

Periodic Trend - Electron Affinity

Answer 20

Energy change when adding e- to atom in its gaseous state

Most elements tend to release energy upon addition of e- (exothermic, -)
Elements with closed shell & closed sub-shell require more energy to add e- (endothermic, +)

More negative left to right, bottom to top

Question 21

Periodic Trend - Electronegativity

Answer 21

Ability of atom to attract e- to itself in a covalent bond
- Metals tend to lose e- in presence of non-metals
FONClBrISCH

Electronegativity increases left to right, bottom to top