BIEN135 ch6-9 MC HW Questions

True or False. A piston containing an ideal gas expands isothermally from 7 atm pressure to 2 atm pressure. The energy of the system (that is, the contents of the piston) remains constant during this process

True

A protein is negatively charged, but it binds a negatively charged small molecule faster than it binds a positively charged small molecule. The most reasonable explanation for this phenomenon is:

a. even though the protein is negatively charged overall, electrostatic focusing effects provide a pathway for a negatively charged molecule to enter the active site

b. the presence of water molecules screen the electrostatic effects

c. the negatively charged molecule makes stronger hydrogen bonds than the positively charged molecule

d. charged proteins normally bind substrates with the same overall charge

even though the protein is negatively charged overall, electrostatic focusing effects provide a pathway for a negatively charged molecule to enter the active site

The enthalpy change for a process is equal to the heat transferred to the system under which of the following conditions?

a. constant volume

b. constant pressure

c. constant temperature

d. reversible expansion

e. expansion at a constant pressure followed by reversible compression

constant pressure

Which of the following properties are extensive (choose all that apply)

temperature, pressure, amount of heat released, density, energy, molarity, number of moles, mass, volume

amount of heat released, energy, number of moles, mass, volume

True or False. Energy is a good indicator of the direction of spontaneous change for macroscopic mechanical objects but not for molecular processes.

True

Which of the following statements about potential energy is true?

a. the potential energy of an ideal gas is equal to its kinetic energy

b. the potential energy of an atom is the work done in moving the atom from infinity to its present position

c. potential energy is always absolutely conserved

d. the potential energy of a system always incerases

e. potential energy is an intensive function

the potential energy of an atom is the work done in moving the atom from infinity to its present position

The type of function that best describes the energy of a hydrogen bond as the distance between the hydrogen atom and the acceptor atom varies between 1.5 and 2.5 A is: a, b, c, or d

a

A reaction that releases energy is called an _____ reaction

exothermic

Electrostatic interactions are governed by ______’s law

Coulomb

True or False. It is easier to predict the bulk behavior of a small number of molecules than a large number of molecules.

False

True or False. Consider a coin with two sides (H=heads; T=tails). The probability of observing HHHHHTTTTT is equal to the probability of observing HTHTHTHTHT.

true

True or False. An isolated molecular system exists in two states of equal energy, State A has high multiplicity, whereas State B has low multiplicity. Without any external agents a system in State B will spontaneously convert to State A.

true

True or False. A state corresponds to many different microsates

true

The work done in a near-equlibrium expansion of an ideal gas is _____ than for a nonequilibrium expansion.

greater

When the volume of a system increases its multiplicity_____

increases

True or False. For the system converting from state 1 to state 2: (kBlnW2-kBlnW1)=qrev/T

true

True or False. If the second lowest energy level is separated from the ground state by 0.5kBT, then the second lowest energy level will not be occupied appreciably

false

Which of the following definitions of etnropy are equivalent for a large system: 

a. probabilistic definition

b. thermodynamic definition

c. statistical definition

d. all of the above

all of the above

After spontaneous heat transfer between systems, the overall multiplicity is:

a. lower than it was before the transfer of heat

b. zero

c. maximized

d. minimized

maximized

The Boltzmann distribution describes the energy of molecules at _____

equilibrium

The Boltzmann constant is the gas constant (R) divided by ________

Avagadro’s number

Kinetic energy is due to the ______ of atoms. Potential energy is due to the _______ of atoms.

motion, configuration/relative positions

The direction of spontaneous change is governed by an increase in ________, thus explaining how energy can be transferred “uphill”, that is from a system of lower total energy to one with higher total energy

entropy/multiplicity

True or False. For a system at equilibrium, Gibbs free energy is maximized

false

The work done by biological systems is most commonly which type of work?

a. pressure

b. chemical

c. home

d. volume

e. heat

chemical

According to Le Chatelier’s principle?

a. a reaction always favors the formation of as much product as possible

b. reactants will only react upon the addition of external heat or pressure

c. the system will adjust, if more reactants are added, and a new equilibrium will be established to balance the change

d. the Gibbs free energy is always greater than the amount of work done plus the Helmholtz free energy

the system will adjust, if more reactants are added, and a new equilibrium will be established to balance the change

True or False. The cell generates ATP from ADP and Pi by coupling the synthesis to an energetically unfavorable process

false

At equilibrium:

a. there is no change in temperature over time

b. the free energy of the system is minimized

c. the combined entropy of the system and surroundings is maximized

d. only b and c

e. a, b, and c

a, b, and c

Gibbs free energy is used to describe systems with constant ______, while Helmholtz free energy is used to describe systems with constant _____

pressure and temperature, volume and temperature

The change in free energy of a process is equal to the ______ amount of work extracted from that process

maximum