Chem Final

Question 1

Define exothermic reaction.

Answer 1

ΔH < 0

Question 2

Define endothermic reaction.

Answer 2

ΔH > 0

Question 3

What is the formula for calculating ΔHrxn?

Answer 3

ΔHrxn = Σ (bonds broken) - Σ (bonds formed)

Question 4

What is the formula for pH?

Answer 4

pH = -log[H+]

Question 5

What is the formula for pOH?

Answer 5

pOH = -log[OH-]

Question 6

What is the relationship between pH and pOH?

Answer 6

pH + pOH = 14

Question 7

What is the value of Kw at 25°C?

Answer 7

Kw = [H+][OH-] = 1.0 × 10⁻¹⁴

Question 8

What is the relationship between Ka, Kb, and Kw?

Answer 8

Ka × Kb = Kw

Question 9

List strong acids.

Answer 9

• HCl
• HBr
• HI
• HNO₃
• HClO₄
• H₂SO₄

Question 10

List strong bases.

Answer 10

• Group 1 hydroxides
• Group 2 hydroxides (e.g., NaOH, Ca(OH)₂)

Question 11

What is the pH at equivalence for a strong acid-strong base titration?

Answer 11

pH = 7

Question 12

What is the pH at equivalence for a weak acid-strong base titration?

Answer 12

pH > 7

Question 13

What does Q equal at equilibrium?

Answer 13

Q = K

Question 14

What happens if Q < K?

Answer 14

Shifts right

Question 15

What happens if Q > K?

Answer 15

Shifts left

Question 16

What is the redox process at the anode?

Answer 16

Oxidation (e⁻ loss)

Question 17

What is the redox process at the cathode?

Answer 17

Reduction (e⁻ gain)

Question 18

What is the rate equation for a zero-order reaction?

Answer 18

Rate = k

Question 19

What is the half-life formula for a zero-order reaction?

Answer 19

t½ = [A]₀ / 2k

Question 20

What is the rate equation for a first-order reaction?

Answer 20

Rate = k[A]

Question 21

What is the half-life formula for a first-order reaction?

Answer 21

t½ = 0.693 / k

Question 22

What is the rate equation for a second-order reaction?

Answer 22

Rate = k[A]²

Question 23

What is the half-life formula for a second-order reaction?

Answer 23

t½ = 1 / (k[A]₀)

Question 24

What does Le Chatelier’s Principle state about adding reactants?

Answer 24

Shifts right

Question 25

What does Le Chatelier's Principle state about removing reactants?

Answer 25

Shifts left

Question 26

What happens when pressure is increased in a gaseous equilibrium?

Answer 26

Shifts to fewer gas moles

Question 27

What happens when temperature is increased in an endothermic reaction?

Answer 27

Favors endothermic direction

Question 28

What is the maximum buffer capacity condition?

Answer 28

[HA] = [A⁻] conjugate base = weak acid

Question 29

What should be chosen for a buffer with a desired pH?

Answer 29

Choose conjugate pair with pKa ≈ desired pH

Question 30

What is the effect of more electronegative atoms on acidity?

Answer 30

Stronger acids

Question 31

What effect does resonance stabilization have on acidity?

Answer 31

Stronger acids

Question 32

What effect do inductive effects have on acids and bases?

Answer 32

Electron-withdrawing groups (+I) destabilize the conjugate base of an acid, increasing its acidity, while electron-donating groups (-I) stabilize the conjugate base, decreasing acidity

Question 33

What is a nucleophile?

Answer 33

Electron-rich species donate electrons (Lewis bases) Examples: OH⁻, NH₃, Cl⁻, H₂O, CN⁻ Stronger nucleophiles: negative charge, less steric hindrance

Question 34

What is an electrophile?

Answer 34

Electron-poor species accept electrons (Lewis acids) Examples: H⁺, carbocations (R⁺), carbonyl carbon (C=O), alkyl halides (R-X) More positive charge or partial positive → stronger electrophile

Question 35

What is a carbocation?

Answer 35

Carbocations are positively charged carbon species. They are intermediates in many important chemical reactions,

Question 36

Sn1 and its features

Answer 36

2 steps: Carbocation forms (the leaving group leaves first — slow step). Nucleophile attacks the carbocation (fast step). Rate depends on: Rate=k[substrate] Weak nucleophile needed

Question 37

Sn2 and its features

Answer 37

1 step: The nucleophile attacks the carbon as the leaving group leaves. Happens in a single, concerted step. Rate=k[substrate][nucleophile] Strong nucleophile needed

Question 38

What is chirality?

Answer 38

A molecule has at least one carbon atom bonded to four different groups — this carbon is called a chiral center or stereocenter.

Question 39

Alkoxy group

Answer 39

An alkoxy group is a functional group with the general formula: R-O-

Question 40

Amino group

Answer 40

An amino group is a functional group with the formula: -NH2

Question 41

Hydroxy group

Answer 41

The hydroxy group is the functional group with the formula: -OH

Question 42

Halo group

Answer 42

A halo group is when a halogen atom is attached to a carbon chain in an organic molecule. Halogens are: Fluorine (F) Chlorine (Cl) Bromine (Br) Iodine (I) General Formula: R–X

Question 43

Whats an isomer?

Answer 43

A molecule that has: The same molecular formula (same number and type of atoms) But a different structure or arrangement of those atoms

Question 44

Stability of carbocations

Answer 44

The one with most R groups is most stable

Question 45

Definition of spontaneity

Answer 45

a spontaneous process is one that occurs naturally, without requiring an external input of energy to procee

Question 46

Will Sn1 or Sn2 lead to a a faster reaction under lab 12 conditions, using primary, secondary, and tertiary, and why?

Answer 46

Sn1 will react the quickest due to us having a stable tertiary intermediate. Tertiary butyl chloride concludes in the fastest reaction and will dissipate the quickest due to its bulkiness, allowing the nucleophile to act quicker.