Exam 1 True/False Practice Flashcards
Which of the following is/are polar?
CH3OCH3
Polar
Which of the following is/are polar?
BrF3
Polar
Which of the following is/are polar?
SF6
Nonpolar
Which of the following is/are polar?
SO3
Nonpolar
Which of the following is/are polar?
C3H8
Nonpolar
Which of the following is/are polar?
SO2
Polar
Intermolecular forces are within molecules; bonds are
between molecules.
False
Bonds are generally weaker than intermolecular forces.
False
The strongest intermolecular force in a pure substance is hydrogen bonding.
True
Dipole-dipole forces are the result of an instantaneous dipole interacting with an induced dipole.
False
Dispersion forces are present between all molecules, but are the only intermolecular force between two non-polar molecules.
True
The strongest intermolecular force between two CH3CHO molecules is hydrogen bonding
False
The strongest intermolecular force between two silicon tetrafluoride molecules is dipole-dipole forces.
False
There are only dipole-dipole forces and dispersion forces between two CH2F2 molecules; there is not hydrogen bonding.
True
There should be dipole-dipole forces and dispersion forces between two C6H14 molecules
False
The strongest intermolecular force between two helium atoms should be dispersion forces.
True
Solids have strong intermolecular forces relative to thermal energy
True
Solids can be categorized as crystalline or amorphous; amorphous solids have no long-range order.
True
We can change from a liquid to a gas by increasing
temperature or increasing pressure.
False
In a liquid, the particles can move with respect to one another, so liquids have an indefinite volume, but definite shape.
False
The strongest intermolecular force between two CH3CHO molecules is hydrogen bonding
False
The strongest intermolecular force between two silicon tetrafluoride molecules is dipole-dipole forces.
False
There are only dipole-dipole forces and dispersion forces between two CH2F2 molecules; there is not hydrogen bonding.
True
There should be dipole-dipole forces and dispersion forces between two C6H14 molecules
False
The strongest intermolecular force between two helium atoms should be dispersion forces.
True
Vaporization is the process of changing a substance from a liquid to a gas
True
The rate of vaporization increases with increasing temperature and surface area, but decreasing intermolecular forces
True
If a liquid is considered volatile, it is explosive
False
Vaporization only occurs at the boiling point of a liquid
False
The energy change for vaporization is the same magnitude, but opposite sign as the energy change for condensation
True
The boiling point of a liquid is when the vapor pressure of the liquid is equal to the external pressure
True
If the pressure above a liquid-vapor system in equilibrium decreases (a disturbance), some of the liquid will evaporate (to minimize the disturbance and restore equilibrium)
True
Dynamic equilibrium is reached when the condensation and vaporization processes stop
False
If you bring a pot of water from sea level to La Paz, Bolivia (11,975 ft above sea level), you will increase its boiling point
False
Another word for fusion is freezing
False
Fusion is an endothermic process, so the enthalpy of fusion is positive
True
Heating a liquid in a closed container until its temperature is beyond the critical temperature produces a supercritical fluid
True
An ice cube slowly disappearing from an ice cube tray in a freezer is an example of sublimation
True
There is no change in temperature when energy is added to a block of ice at its freezing point until all the ice has melted
True
Enthalpy of fusion generally decreases with increasing strength of intermolecular forces
False
solution that contains more dissolved solute than the equilibrium amount is supersaturated
True
Solubility of most solids decreases with increasing temperature
False
Solubility of most gases increases with increasing pressure and temperature.
False
An unsaturated solution contains less than the equilibrium amount of solute
True
solution in which the dissolved solute is in dynamic equilibrium with the solid (undissolved) solute is a saturated solution
True
When a solution forms, the solute-solute interactions must be overcome, so ΔHsolute is endothermic
True
When a solution forms, the solvent-solvent interactions must be overcome, so ΔHsolvent is endothermic
True
ΔHmix is endothermic
False
The heat of hydration is the enthalpy change that occurs when 1 mole of the gaseous solute ions are dissolved in water; it is always largely negative (exothermic) for ionic compounds
True
Colligative properties depend on the number of particles dissolved in solution, not on the type of particles
True
Vapor pressure increases as the mol fraction of solute dissolved in the solvent increases
False
Dissolving a nonvolatile solute into a solvent decreases its vapor pressure
True
If the solute is volatile, it also contributes to the overall vapor pressure of the solution
True
0.02 M FeBr3 solution will have the same osmotic pressure as a 0.02 M AlCl3 solution, assuming ideal Van Hoff factors.
True
An aqueous 0.03 m NaCl solution will have a higher boiling point than an aqueous 0.04 m C6H12O6 (glucose) solution, assuming ideal Van Hoff factors.
True
The measured Van Hoff factor can be larger than the ideal when there is ion pairing.
False
An aqueous 0.02 m HCl solution will have a higher boiling point than an aqueous 0.02 m HF (a weak acid) solution.
True
According to collision theory, rate of reaction increases with decreasing temperature because more particles have enough energy to overcome the activation energy
False
According to collision theory, rate of reaction increases with increasing concentration because particles are more likely to collide with one another
True
For the reaction 2 A + B + C –> 3 D + E, if the rate at an instant in time is –0.12 M/s for A, then the rate for D is +0.08 M/s.
False
Rate of reaction generally decreases with time.
True
For the reaction A –> B + 2C where the reaction is determined to be first order, if the initial rate is 0.01 M/s when [A] = 0.10 M, then the initial rate will be 0.02 M/s when [A] = 0.20 M.
True
For the reaction A –> 2 B where the reaction is determined to be second order, if the initial rate is 0.001 M/s when [A] = 0.10 M, then the initial rate will be 0.016 M/s when [A] = 0.40 M.
True
For the reaction A –> B where the reaction is determined to be zero order, if the initial rate is 0.1 M/s when [A] = 2.0 M, then the initial rate will be 0.2 M/s when [A] = 4.0 M.
False
For the reaction A + B + 2 C –> 3 D + E, if the rate law is Rate = k [A][C], then the overall order of the reaction is 4.
False
The integrated rate law shows how the rate depends on concentration; the differential rate law shows how concentration depends on time
False
In the integrated rate law, k is the same rate constant as in the differential rate law
True
The rate law (differential rate law) must be determined experimentally; the integrated rate law is derived from the rate law mathematically
True
When the inverse of the concentration of reactant X is plotted vs time, a straight line will result if the reaction is zero-order in X
False
When the natural log of the concentration of a reactant X is plotted vs time, a straight line will result if the reaction is first-order in X
True
The first half-life for the reaction 2A -> A2 is 20 seconds. The second half-life is 10 seconds. This reaction is second order.
False
The first half-life for the reaction 2B -> B2 is 20 seconds. The second half-life is 40 seconds. This reaction is zero order.
False
The first half-life for the reaction 2C -> C2 is 15 seconds. Each half-life thereafter is 15 seconds. This reaction is first order.
True
