125 Questions
Free Energy (G) has two components, Enthalpy (H) and Entropy (S)?
True
The Law of Conservation of Energy states that energy can be created but not destroyed?
False
Changes in entropy deal with changes in chemical bonding or non-covalent interactions?
False
Energy comes in two main types: Kinetic energy and Mechanical energy?
False
Enthalpy has a larger contribution to free energy at high temperatures?
False
Hess’ Law deals with changes in equilibrium and Gibbs Free Energy?
False
Energy can be created and destroyed according to the law of thermodynamics.
False
The surroundings in a thermodynamic system refer to the vessel of interest where reactions take place.
False
An open system can exchange both energy and matter with its surroundings.
True
Adiabatic barriers allow for efficient energy transfer between the system and surroundings.
False
If A is in thermal equilibrium with B, and B is in thermal equilibrium with C, then A will also be in thermal equilibrium with C according to the Zeroth Law of Thermodynamics.
True
Work is required to push air from the lungs against atmospheric pressure.
True
A system does the most work possible when the opposing pressure is greater than the internal pressure.
False
The heat capacity of a substance can be used to obtain the quantity of transferred heat via q = CΔT.
True
For reversible isothermal expansion of a perfect gas, the internal energy ΔU is equal to zero.
True
The internal energy of a system refers to the total energy (kinetic + potential) of all the atoms, molecules, and ions constituting the system.
True
The first law of thermodynamics states that isolated systems can do work upon or heat their surroundings.
False
For any system that does work, new sources of energy must be supplied at regular intervals.
True
Enthalpy equals the change in internal energy plus the product of pressure and change in volume.
True
For an open system with external pressure pex, the change in enthalpy equals the heat transferred at constant pressure.
True
An exothermic process involves energy leaving the system as heat and has a positive change in enthalpy.
False
The heat capacity at constant pressure, Cp, is equal to the change in enthalpy divided by the change in temperature.
True
The standard molar enthalpy of a substance is denoted by Hmo and represents its enthalpy at 25°C and exactly 1 bar pressure.
True
The vaporization enthalpy of water is responsible for the high humidity of our climate and the presence of oceans.
False
Sublimation is the direct conversion of a solid to a liquid.
False
Differential Scanning Calorimetry measures the difference in heat transferred to or from a sample in comparison to a reference material.
True
The overall enthalpy change of a process is equal to the sum of the sublimation and vaporization enthalpies.
False
Breaking bonds (dissociation) are always exothermic processes.
False
Entropy is the measure of how concentrated energy and matter is.
False
The entropy of an isolated system tends to decrease.
False
The change in entropy of a substance is equal to the heat transferred reversibly to it divided by the temperature at which the transfer takes place.
True
Entropy is not a state function.
False
When increasing the number of energy packets over 80 atoms, the probability of the hot bar getting hotter increases.
False
The resulting change in entropy when transferring 100 kJ of heat to a large body of water at 0 °C is +366 J K-1.
True
Melting or boiling results in a decrease in entropy.
False
The entropy of vaporization of water at 25 °C is -118 J K-1 mol-1.
False
Humans, even at rest, do not constantly expend energy.
False
At absolute zero, the absolute entropies of all perfectly crystalline substances are zero.
True
Standard molar entropies can be obtained by following the changes in heat capacity of a given substance with temperature.
True
Entropy can be negative for a substance at a certain temperature.
True
Hydrogen peroxide is formed in the body due to reactions involving oxygen.
True
The enthalpy change for the reaction 2H2O2(l) ➞ 2H2O(l) + O2(g) is -172 kJ.
True
Standard enthalpy of combustion for CH4(g) is -890 kJ mol-1.
True
Fats are used for energy storage in mammals and to provide insulation.
True
Proteins are usually used to create new proteins instead of being employed as a fuel source.
True
The standard enthalpy of a reaction is the sum of the standard enthalpies of the reactions into which the overall reaction may be divided.
True
During vigorous exercise, muscle cells become deprived of oxygen, leading to the production of lactic acid (LA).
True
Isothermal expansion of a perfect gas into a vacuum has no overall change in energy.
True
Gas molecules move randomly, and the probability that they will move into one corner of a container is significant.
False
Spontaneous processes necessarily move in the direction of lower energy.
False
Gases expand to fill empty spaces, which is a non-spontaneous process.
False
In a cooling process, the energy lost by the system is destroyed and cannot be transferred to the surroundings.
False
The standard reaction entropy, ΔrS∅, is the difference in molar entropy between the products and reactants of a reaction in their standard states?
True
The standard reaction entropy of an enzyme catalyzed reaction at 25 °C is +96.3 J K-1 mol-1?
False
Processes occur spontaneously if the overall entropy of the universe is decreased?
False
According to the 2nd Law of Thermodynamics, the entropy of an isolated system tends to decrease?
False
The Gibbs energy and Entropy have the same signs?
False
Josiah Willard Gibbs was the first person to receive a PhD in Engineering from Yale?
True
The ΔG of any process is the maximum expansion work that can be extracted from that process at constant temperature and pressure?
False
The change in Gibbs energy accompanying combustion of glucose at 25 °C is +2828 kJ mol-1?
False
ATP hydrolysis drives favorable biochemical reactions?
True
The standard reaction Gibbs energy, ΔrGo, can be calculated using tabulated values obtained by combining standard enthalpies and entropies?
True
Which component of free energy has a higher contribution at higher temperatures?
Entropy
What type of energy is associated with movement?
Kinetic energy
In the equation G = H - TS, what does 'T' represent?
Temperature
According to the text, what type of energy is possessed due to position?
Potential energy
What does the equation ∆Gⱡ = ∆Hⱡ - T∆Sⱡ represent?
Non-standard Gibbs free energy change
What deals with changes in order or disorder associated with a process?
Entropy
What is the standard enthalpy of combustion for CH4(g)?
-890 kJ mol-1
What type of process is the isothermal expansion of a perfect gas into a vacuum?
Spontaneous process
Which statement about spontaneous processes is true?
They always move in the direction of lower energy.
What is the standard enthalpy of formation of liquid water?
-286 kJ mol-1
What drives favorable biochemical reactions?
ATP hydrolysis
What happens during vigorous exercise when muscle cells become deprived of oxygen?
Glucose cannot be completely oxidized and is broken down to lactic acid
What is the enthalpy change for glycolysis?
-120 kJ
What is the energy input required per day for 18-20 year old males?
~12 MJ
Which type of fuel provides 17 kJ g-1?
Carbohydrates
What do proteins do in mammals?
Used to create new proteins instead of being employed as a fuel source
What happens to fats in mammals?
Are used for energy storage
How does body temperature regulated?
Radiation and perspiration
What is the standard reaction entropy, ΔrS∅, for the reaction catalyzed by carbonic anhydrase?
-96.3 J K-1 mol-1
What does the change in Gibbs energy, ΔG, represent for any process?
Non-expansion work
At pH = 7.0 and T = 37 °C, what is the standard enthalpy change, ΔrH, for ATP hydrolysis?
-20 kJ mol-1
What is the relationship between Gibbs energy and entropy for spontaneous processes?
They have opposite signs
What is the maximum nonexpansion work that can be extracted from a process at constant temperature and pressure?
ΔG
What is the standard reaction Gibbs energy, ΔrGo, for the reaction catalyzed by carbonic anhydrase at 25 °C?
-274.6 kJ mol-1
What drives unfavourable biochemical reactions by providing up to 31 kJ of energy in the form of non-expansion work?
ATP hydrolysis
What is the relationship between Gibbs energy and spontaneity?
-ΔG leads to spontaneous processes
At what temperature are the absolute entropies of all perfectly crystalline substances zero?
+0 K
What happens to Gibbs energy and entropy for spontaneous processes?
-ΔG and +ΔS
If a process has a change in Gibbs energy of -2828 kJ mol-1 at 25 °C, what type of work does it represent?
Non-expansion work
What is the relationship between Gibbs energy and enthalpy for any process?
They have opposite signs
What is the measure of how dispersed energy and matter is?
Entropy
What is the change in entropy of a substance equal to?
$q_{rev}/T$
What is the probability that we end up with 9 packets in the HOT bar, and 1 packet in the COLD bar?
91520
What happens to the probability of the hot bar getting hotter as we increase the number of energy packets over 80 atoms?
Drops drastically
What is the standard molar entropy, Sm∅, the measure of?
Absolute entropies at absolute zero
In which scenario does entropy change, ΔS, increase?
$ ext{Cp} imes ext{ln} (T_f/T_i)$ when $T_f > T_i$
What does melting or boiling result in?
Increase in entropy
What does the standard molar entropy, Sm∅, measure?
$ ext{Sm}∅$ of perfectly crystalline substances at absolute zero
What does a person at rest constantly expend?
$100 J s^{-1}$
What does the Third Law of Thermodynamics state?
$ ext{S}(0) = 0$
"The amount of heat passing to / from the surroundings is equal and opposite to the heat leaving / entering the system". What does this statement imply?
$ΔS_{sur} = -ΔH/T$
"Josiah Willard Gibbs was the first person to receive a PhD in Engineering from Yale?". Is this statement true?
"False"
What is the fundamental principle of the conservation of energy?
Energy is constant and cannot be created or destroyed
What is the system in thermodynamics?
The vessel of interest where reactions take place
Which type of system can exchange energy but not matter with its surroundings?
Closed system
What is the sign convention for work done on a system?
Positive if work is done on the system
What is the formula for work associated with gas expansion?
$w = -pexΔV$
What happens when work is required to push air from the lungs against atmospheric pressure?
Negative work is done
What does the first law of thermodynamics state about the internal energy of a perfect gas during isothermal expansion?
$ΔU = 0$
What is internal energy in thermodynamics?
The total energy of all subatomic particles in a system
How can the quantity of heat transferred be obtained using heat capacity?
$q = CΔT$
In thermodynamics, what does the first law state about isolated systems?
Isolated systems can neither do work upon nor heat their surroundings.
What is the relationship between enthalpy change (ΔH) and heat transferred (q) for an exothermic process?
ΔH = -q
What is responsible for the low humidity of the climate and the presence of oceans, according to the text?
Vaporization enthalpy of water
What does sublimation refer to in thermodynamics?
Direct conversion of a solid to a gas
What does differential scanning calorimetry measure?
Difference in heat capacity of a substance with temperature
What represents the standard molar enthalpy of a substance?
$H_m = U_m + RT$ at 25 °C
What is the standard reaction entropy (ΔrS∅) used to measure?
Difference in molar entropy between products and reactants at standard conditions
What is responsible for the high vaporization enthalpy of water?
Hydrogen bonding
What does the standard reaction Gibbs energy ($ ext{ΔrG∅}$) represent?
$ ext{ΔrG∅}$ can be calculated using tabulated values obtained by combining standard enthalpies and entropies.
What does the standard molar enthalpy ($H^o_m$) represent?
$H^o_m$ represents the enthalpy at 25 °C and exactly 1 bar pressure.
What contributes to the low humidity of our climate and presence of oceans?
Vaporisation: ΔvapHo (H2O) = +44 kJ mol-1.
Which process involves energy entering the system as heat?
Vaporisation: ΔvapHo (H2O) = +44 kJ mol-1.
Test your knowledge of bond enthalpy calculations with a focus on estimating the enthalpy change for the decomposition of hydrogen peroxide using mean bond enthalpies. The quiz will involve understanding the process of bond breaking and forming in the gas phase, and taking into account relevant state changes.
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