chem exam 4 - T/F

Question 1

the only intermolecular force found in H2O is hydrogen bonding - a subset of dipole - dipole interactions

Answer 1

false

Question 2

the strongest intermolecular force found in H2S is dipole-dipole interaction.

Answer 2

true

Question 3

alkanes are saturated hydrocarbons, while alkenes are unsaturated hydrocarbons

Answer 3

true

Question 4

there are only two structural isomers possible for C4H10

Answer 4

true

Question 5

the only intermolecular force found in NH3 is hydrogen bonding

Answer 5

false

Question 6

the strongest intermolecular force found in CO2 is dipole-dipole interaction

Answer 6

false

Question 7

alkanes are unsaturated hydrocarbons, while alkynes are saturated hydrocarbons

Answer 7

false

Question 8

there are three structural isomers possible for C5H12

Answer 8

true

Question 9

colligative properties of solutions depend on the number of solute particles present in the
solution

Answer 9

true

Question 10

dissolving a solute in a solvent lowers the vapor pressure of the resulting solution
compared to the pure

Answer 10

true

Question 11

the greater the energy of activation Ea, the slower the reaction will be

Answer 11

true

Question 12

osmotic pressure is the force required to prevent the movement of solvent molecules
through a semi-permeable membrane

Answer 12

true

Question 13

the rate law can be readily predicted from the balanced chemical equation of a reaction

Answer 13

false

Question 14

the half-life of a first-order reaction remains constant regardless of the initial
concentration of the reactant

Answer 14

true

Question 15

the boiling point elevation of a solution dependents on the type of solute particles
dissolved in the solvent

Answer 15

false

Question 16

the addition of a non-volatile solute to a solvent would result in a decrease in the
solvent’s vapor pressure

Answer 16

true

Question 17

a higher activation energy (Ea) gives a higher reaction rate

Answer 17

false

Question 18

the osmotic pressure of a solution is the pressure needed to halt the osmotic flow of
solvent into the solution

Answer 18

true

Question 19

in a first-order reaction, the half-life is independent of the amount of reactant present at the start

Answer 19

true

Question 20

although a system may be at equilibrium, the rate constants of the forward and reverse
reactions will in general be different

Answer 20

true

Question 20

when a reaction system reaches equilibrium, the forward and reverse reactions stop

Answer 20

false

Question 21

a chemical reaction will reach equilibrium when the limiting reactant is used up

Answer 21

false

Question 22

if all the reactants and products in an equilibrium reaction are in the gas phase, then Kp = Kc

Answer 22

false (only when delta n = 0)

Question 23

all Brønsted-Lowry bases contain the hydroxide ion, OH–

Answer 23

false

Question 24

all Brønsted-Lowry bases are H+ ion acceptors

Answer 24

true

Question 25

if a strong acid such as HCl is diluted sufficiently with water, the pH will be higher than 7

Answer 25

false

Question 26

at equilibrium, the concentrations of reactants and products remain constant, but the rates of the forward and reverse reactions are different

Answer 26

false

Question 26

when a reaction system reaches equilibrium, the forward and reverse reactions continue at equal rates

Answer 26

true

Question 27

at equilibrium, the reaction stops because the limiting reagent is completely consumed

Answer 27

false

Question 28

for a reaction at equilibrium where all reactants and products are gases, the equilibrium constant expressed in terms of partial pressures (Kp) is equal to the equilibrium constant expressed in terms of concentrations (Kc)

Answer 28

false

Question 29

if an acid dissociates completely in water, it is a strong acid

Answer 29

true

Question 30

dispersion forces are only present in molecules with no dipole moments

Answer 30

false

Question 31

the strongest intermolecular force found in hexane (CH3CH2CH2CH2CH2CH3) is dipole- dipole interaction

Answer 31

false

Question 32

the phase diagram of a substance can be used to obtain the boiling point of that substance at a given atmospheric pressure

Answer 32

true

Question 33

molality is defined as moles of solute/kg of solvent

Answer 33

true

Question 34

the osmotic pressure is defined as the pressure applied across a membrane to stop the flow of solvent through membrane

Answer 34

true

Question 35

the temperature at which the vapor pressure of a substance equals 1 atm is called its normal boiling point

Answer 35

true

Question 36

the enthalpy of vaporization (∆𝐻vap) can be obtained from the Clausius–Clapeyron equation

Answer 36

true

Question 37

dispersion forces are only present in molecules with or without dipole moments

Answer 37

true

Question 38

the strongest intermolecular force found in ethanol (CH3CH2OH) is hydrogen bonding interaction

Answer 38

true

Question 39

the higher the charge density of an ion, the greater the magnitude will be its heat of hydration

Answer 39

true

Question 40

molality is defined as moles of solute/kg of solution

Answer 40

false

Question 41

osmotic pressure is directly proportional to the temperature measured in Kelvin

Answer 41

true

Question 42

the temperature at which the vapor pressure of a substance equals 760 torr is called its normal boiling point

Answer 42

true

Question 43

the enthalpy of vaporization (∆𝐻vap) can be obtained from the Clausius–Clapeyron equation

Answer 43

true

Question 44

the freezing point depression of a solution depends on both the type and quantity of solute particles dissolved in it

Answer 44

false

Question 45

the rate law of the following reaction can be predicted from its balanced equation

Answer 45

false

Question 46

the greater the energy of activation Ea is, the fast the reaction will be

Answer 46

false

Question 47

the unit of the rate of reaction depends on the order of the reaction

Answer 47

false

Question 48

a transition state is a species (or state) corresponding to an energy maximum on a reaction energy diagram

Answer 48

true

Question 49

in a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction

Answer 49

true

Question 50

a catalyst lowers the energy of activation and alters the mechanism of a reaction

Answer 50

true

Question 51

the half-life of a zero-order reaction does not depend on the initial concentration of the reactant

Answer 51

false

Question 52

the half-life of a first-order reaction does not depend on the initial concentration of the reactant

Answer 52

true

Question 53

osmotic pressure of a solution depends on its temperature measured in kelvin

Answer 53

true

Question 54

the theoretical van ’t Hoff Factor (i) for glucose, C6H12O6 is 1

Answer 54

true

Question 55

the boiling point elevation of a solution depends on only the quantity of solute particles, not on the identity of solute particles dissolved in it

Answer 55

true

Question 56

the energy of activation Ea is the energy barrier that reactants must overcome to transform into products

Answer 56

true

Question 57

the unit of the rate of reaction is independent of the order of the reaction

Answer 57

true

Question 58

the higher the energy of activation Ea a reaction has, the harder it is for the reaction to reach a transition state

Answer 58

true

Question 59

an increase in temperature increases the reaction rate because more collisions will have enough energy to exceed the activation energy

Answer 59

true

Question 60

a catalyst can increase the reaction rate by providing an alternative reaction pathway with a lower activation energy

Answer 60

true

Question 61

the half-life of a zero-order reaction decreases as the initial concentration of the reactant decreases

Answer 61

true

Question 62

when both of their concentrations are at 0.10 m, the Na₂CO₃ solution has a higher osmotic pressure and higher boiling point than the LiCl solution

Answer 62

true

Question 63

the theoretical van ’t Hoff factor (i) for potassium chloride is 1

Answer 63

false

Question 64

in a chemical reaction, increasing the temperature will change the value of the equilibrium constant Kc

Answer 64

true

Question 65

for a gas-phase equilibrium, changing the volume of the container will alter the equilibrium constant (Kp)

Answer 65

false

Question 66

if all of the coefficients in the balanced equation for an equilibrium reaction are doubled, then the value of the equilibrium constant, Kc, will also be doubled

Answer 66

false

Question 67

the strongest base which can exist in water is the hydroxide ion OH-

Answer 67

true

Question 68

the solution of sodium acetate (CH3COONa) in water is weakly basic

Answer 68

true

Question 69

hydrated metal ions in aqueous solution can act as Brønsted-Lowry acids

Answer 69

true

Question 70

all Brønsted-Lowry bases have at least one lone pair of electrons

Answer 70

true

Question 71

the equivalence point in a titration is defined as the point when the indicator changes color

Answer 71

false

Question 72

if the pH of a buffer solution is greater than the pKa value of the buffer acid, the buffer will have more capacity to neutralize added base than added acid

Answer 72

false

Question 73

increasing the concentrations of the components of a buffer solution will increase the buffer capacity

Answer 73

true

Question 74

electrolyte cells utilize electrical energy to drive non-spontaneous redox reactions

Answer 74

true

Question 75

for the reaction occurring in a voltaic (galvanic) cell, DG>0

Answer 75

false

Question 76

oxidation occurs at the cathode of a galvanic cell

Answer 76

false

Question 77

electrons are produces at the cathode of a voltaic cell

Answer 77

false

Question 78

if the electrodes of a voltaic cell are connected with an external wire, electrons will flow in this wire from the cathode to the anode

Answer 78

false

Question 79

a salt bridge provides a path for electrons to move between the anode and cathode compartments of a voltaic cell

Answer 79

false

Question 80

in the shorthand notation for cells, a double vertical line represents a salt bridge

Answer 80

true

Question 81

the higher the pressure of a gas sample, the greater is its entropy

Answer 81

false

Question 82

the entropy of one mole of oxygen gas in a 0.5-L container is less than it would be in a 22.4-L container at the same temperature

Answer 82

true

Question 83

in a spontaneous process, the entropy of the system always increases

Answer 83

false (entropy of universe always increasing)

Question 84

in some spontaneous processes, the entropy of the surroundings decreases

Answer 84

true

Question 85

for a reaction at equilibrium, ΔSuniv = 0

Answer 85

true

Question 86

as a chemical reaction proceeds toward equilibrium, the free energy of the system decreases

Answer 86

true