CHEM 105A- EXAM 3

Question 1

What is the sign of q for an endothermic process?

Answer 1

q > 0

Question 2

What is the sign of q for an exothermic process?

Answer 2

q < 0

Question 3

What is the formula for internal energy (DeltaU)?

Answer 3

DeltaU = q + w

Question 4

What does w represent in thermochemistry?

Answer 4

w = -PDeltaV

Question 5

In coffee cup calorimetry, what is the relationship between q_rxn and q_solution?

Answer 5

q_rxn = -q_solution

Question 6

In bomb calorimetry, what is the relationship between q_rxn and DeltaT?

Answer 6

q_rxn = -C_cal·DeltaT

Question 7

What is the equation that relates the speed of light, wavelength, and frequency?

Answer 7

c = wavelength x frequency

Question 8

What is Planck’s constant (h)?

Answer 8

h = 6.626x10⁻³ J·s

Question 9

What is the speed of light (c)?

Answer 9

c = 3.00x10⁸ m/s

Question 10

True or False: Energy is quantized.

Answer 10

True

Question 11

What is the trend in energy with frequency?

Answer 11

Higher frequency = higher energy

Question 12

Define a covalent bond.

Answer 12

Sharing electrons (nonmetals)

Question 13

Define an ionic bond.

Answer 13

Transfer of electrons (metal + nonmetal)

Question 14

What is a metallic bond?

Answer 14

Delocalized electrons among metal atoms

Question 15

What is the octet rule?

Answer 15

Most atoms aim for 8 valence electrons

Question 16

What is electronegativity?

Answer 16

Ability to attract electrons in a bond

Question 17

What is the range for nonpolar covalent bonds in terms of DeltaEN?

Answer 17

DeltaEN < 0.4

Question 18

What is the DeltaEN range for polar covalent bonds?

Answer 18

DeltaEN 0.4-2.0

Question 19

What is the DeltaEN threshold for ionic bonds?

Answer 19

DeltaEN > 2.0

Question 20

What hybridization corresponds to 2 electron groups?

Answer 20

sp

Question 21

What is the geometry for sp² hybridization?

Answer 21

Trigonal planar

Question 22

What hybridization corresponds to 4 electron groups?

Answer 22

sp³

Question 23

What geometry is associated with dsp³ hybridization?

Answer 23

Trigonal bipyramidal

Question 24

What hybridization corresponds to 6 electron groups?

Answer 24

d²sp³

Question 25

What type of bond is formed by head-to-head overlap?

Answer 25

Sigma (σ) bonds

Question 26

What type of bond is formed by side-to-side overlap?

Answer 26

Pi (π) bonds

Question 27

What is Boyle's Law?

Answer 27

PV = PV (inverse relationship)

Question 28

What does Charles' Law state?

Answer 28

V/T = constant (direct relationship)

Question 29

What is Avogadro's Law?

Answer 29

V ∝ n (direct relationship)

Question 30

What is the Ideal Gas Law equation?

Answer 30

PV = nRT

Question 31

What is the value of R in the Ideal Gas Law?

Answer 31

R = 0.08206 L·atm/mol·K

Question 32

How do you convert Celsius to Kelvin?

Answer 32

Temperature in Kelvin = degC + 273

Question 33

What is the equivalent of 1 atm in mmHg?

Answer 33

1 atm = 760 mmHg

Question 34

What is the equivalent of 1 atm in Pascals?

Answer 34

1 atm = 101,325 Pa

Question 35

Rank the strength of intermolecular forces from weak to strong.

Answer 35

dispersion < dipole-dipole < H-bond < ionic

Question 36

What is the relationship between stronger IMFs and boiling point?

Answer 36

Stronger IMFs = higher boiling point

Question 37

In which bonds does H-bonding occur?

Answer 37

H-N, H-O, H-F

Question 38

Define surface tension.

Answer 38

Resistance to surface increase

Question 39

What is viscosity?

Answer 39

Resistance to flow

Question 40

What happens to polarizability with increasing molar mass?

Answer 40

Polarizability increases with molar mass

Question 41

What are strong electrolytes?

Answer 41

Completely ionize (e.g., NaCl, HCl)

Question 42

What are weak electrolytes?

Answer 42

Partially ionize (e.g., HF, NH₄⁺)

Question 43

What are nonelectrolytes?

Answer 43

Dissolve without ionizing (e.g., sugar)

Question 44

What solubility rules apply to Group 1 and NH₄⁺ salts?

Answer 44

Soluble

Question 45

What does Henry's Law state?

Answer 45

C = kP (solubility ∝ pressure)

Question 46

Fill in the blank: 'Like dissolves ______.'

Answer 46

like