Term
| When Gibbs energy of a reaction (ΔrG) is negative, the reaction is/isn't spontaneous |
|
Definition
| is spontaneous (shifts to the right) |
|
|
Term
| Volume of 0.03 mol of hydrogen (as an ideal gas) at 1 bar and 25 C is ___ cm^3 |
|
Definition
|
|
Term
| Molecular hydrogen is oxidative/reductive/neutral |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| The universal gas constant is ___ |
|
Definition
8.314 J/mol*K
0.08205 L*atm/mol*K |
|
|
Term
| The chemical formula of methanol is ___ |
|
Definition
|
|
Term
| If atmospheric pressure is 1 bar, the partial pressure of oxygen in air is about ___ bar |
|
Definition
|
|
Term
| The redox number of oxygen in most chemical compounds is ___ |
|
Definition
|
|
Term
| When enthalpy of a reaction (ΔrH) is negative, the reaction is endothermal/exothermal |
|
Definition
|
|
Term
| If hydrogen is used in a fuel cell, the output(s) is(are) ___ |
|
Definition
| water, electricity, and heat |
|
|
Term
| How developed is the technology for the electrolytic production of hydrogen? |
|
Definition
|
|
Term
| Development of the hydrogen technology would need ___ gov't support |
|
Definition
|
|
Term
| An idea on hydrogen technology was primitively described by |
|
Definition
|
|
Term
| Penn State ___ a hydrogen fuel station |
|
Definition
|
|
Term
| The electrical efficiency of a fuel cell can be up to ___% |
|
Definition
|
|
Term
| Molecular hydrogen ___ occurs in nature |
|
Definition
|
|
Term
| Portable fuel cell chargers are ___ on the market |
|
Definition
|
|
Term
| The total (electrical + heat) efficiency of a fuel cell can be up to ___% |
|
Definition
|
|
Term
| Methane is an electron-___ compound |
|
Definition
|
|
Term
| Hydrogen is the ___ element |
|
Definition
|
|
Term
| One of the main advantages of fuel cell technology is high ___ |
|
Definition
|
|
Term
| A fuel cell can directly convert ___ of a fuel to electricity |
|
Definition
|
|
Term
| Fuel cell cellular phones are ___ on the market |
|
Definition
|
|
Term
| Hydrogen has ___ isotopes |
|
Definition
|
|
Term
| The range of H2 flammability in air (at 1 bar) is ___ to ___% |
|
Definition
|
|
Term
|
Definition
|
|
Term
| The engineering principles of fuel and electrolytic cells are similar/different |
|
Definition
|
|
Term
| ___ has the largest energy content per unit of weight |
|
Definition
|
|
Term
| H2O has ___ bonds between molecules |
|
Definition
|
|
Term
|
Definition
|
|
Term
| One of the main disadvantages of the fuel cell technology is ___ |
|
Definition
|
|
Term
Presently, hydrogen is mostly used for
___ |
|
Definition
|
|
Term
| In PA, there are ___ hydrogen fuel stations |
|
Definition
|
|
Term
| Hydrogen and fuel cell technologies are usable/unusable for renewable energy conversion |
|
Definition
|
|
Term
The power output of a fuel cell can be
from ___ to ___ |
|
Definition
|
|
Term
| The carbon-to-hydrogen ratio in methane is ___ |
|
Definition
|
|
Term
| The present gov't strongly supports R&D in ___ power generation |
|
Definition
|
|
Term
| Stationary fuel cells are currently on market in what country? |
|
Definition
|
|
Term
| Ammonia is an electron-___ compound |
|
Definition
|
|
Term
| Hydrogen can be used to produce both ___ and ___ power |
|
Definition
|
|
Term
| Hydrogen usually chemically/electrochemically reacts as ___ |
|
Definition
|
|
Term
| The Honda FCX fuel cell car can be purchased/leased where? |
|
Definition
|
|
Term
The first hydrogen fuel and electrolytic cells were demonstrated by
___ |
|
Definition
|
|
Term
| Cost of hydrogen produced via water electrolysis without using nuclear energy is low/high |
|
Definition
|
|
Term
| The U.S. Hydrogen Fuel Initiative was announced in what year? |
|
Definition
|
|
Term
| Hydrogen is an energy ___ |
|
Definition
|
|
Term
| Hydrogen can be used to (store electricity using an electrolyzer)/(produce electricity using a fuel cell) |
|
Definition
|
|
Term
| In a fuel cell, the cathode is ___ charged |
|
Definition
|
|
Term
| Efficiency of converting electricity to hydrogen can be ___% |
|
Definition
|
|
Term
| Reduction occurs at the ___ |
|
Definition
|
|
Term
| A galvanic electrochemical system turns ___ into ___ |
|
Definition
| chemicals into electricity |
|
|
Term
| Find the cell potential difference of the Daniell cell at STP if activities of Zn2+(aq) and Cu2+(aq) are, respectively, 0.1 and 0.001 |
|
Definition
|
|
Term
| H2->2 H+ + 2e- is a(n) ___ rxn |
|
Definition
|
|
Term
| A H2/O2 PEMFC has two ___ |
|
Definition
|
|
Term
| Estimate the standard electrode potential at STP of the oxygen electrode, the half reaction of which is (1/2) O2(g) +2H+(aq) + 2e- = H2O(l) |
|
Definition
|
|
Term
| The Daniell Cell’s electrodes are what elements? |
|
Definition
|
|
Term
| Find the standard Gibbs energy (ΔrG°) of rxn of decomposition of liquid water to gaseous hydrogen and oxygen at STP |
|
Definition
|
|
Term
| The IUPAC recommendation is that the cell potential difference is left/right potential minus left/right potential |
|
Definition
| right potential - left potential |
|
|
Term
| The electrolyzer anode is ___ charged |
|
Definition
|
|
Term
| Find the standard enthalpy (ΔrH°) of rxn of decomposition of liquid water to gaseous hydrogen and oxygen at 100 °C and 1 bar |
|
Definition
|
|
Term
| Find the standard electrode potential difference (E°) of the Daniell cell (at 25 °C) if pressure is 1000 MPa |
|
Definition
|
|
Term
An electrolytic electrochemical system
turns ___ into ___ |
|
Definition
| electricity into chemicals |
|
|
Term
| Oxidation occurs at the ___ |
|
Definition
|
|
Term
| Find the standard electrode potential difference (E°) of the Daniell cell (at 1 bar) if temperature is 150 °C |
|
Definition
|
|
Term
| The fuel cell anode is ___ charged |
|
Definition
|
|
Term
| A classical electrochemical cell (e.g. Daniell Cell) consists of what? |
|
Definition
electrodes
electrolytes
salt bridge |
|
|
Term
| Find the standard electrode potential difference (E°) of a fuel cell that consumes hydrogen and oxygen and produces gaseous water at 1000 K and 1 bar |
|
Definition
|
|
Term
| Find the standard electrode potential difference (E°) of the Daniell cell (1.101 V at 25 °C) if the left-hand Zn2+/Zn electrode is replaced by the SHE |
|
Definition
|
|
Term
| If Galvani potential is about 1 V, the electrochemical reaction rate can be increased by ___ orders of magnitude |
|
Definition
|
|
Term
| The most common two contributions to an electrochemical reaction are ___ and ___ |
|
Definition
electron transfer
mass transfer |
|
|
Term
| Tafel plot can be used to experimentally estimate ___ and ___ |
|
Definition
exchange current density
transfer coefficient |
|
|
Term
| Concentration overpotential is related to ___ |
|
Definition
| transport of the electrochemically active species |
|
|
Term
| Three-electrode electrochemical cell allows the study of the electrochemical kinetics of ___ |
|
Definition
|
|
Term
| 2 H+(aq) + 2e- = H2(g) is a ___ rxn |
|
Definition
|
|
Term
| Based on the generalized Butler-Volmer equation, you can conclude that when the cathodic current approaches its limiting value, the overpotential goes to ___ |
|
Definition
|
|
Term
0.5 O2(g) + 2 H+(aq) + 2e- = H2O(l) is
a ___ rxn |
|
Definition
|
|
Term
| The charge transfer electrochemical kinetics is based on ___ |
|
Definition
|
|
Term
| The net current density is defined as ___ minus ___ |
|
Definition
| anodic current density minus cathodic one |
|
|
Term
| Using Butler-Volmer equation, calculate the current density for hydrogen half reaction at 25 °C and ovepotential of 50 mV if the exchange current density (jo) is 0.001 A/cm2 and the transfer coeff (α) is 0.5 |
|
Definition
|
|
Term
| When the exchange current density is 10^-2 A/cm2 the electrochemical reaction is ___ |
|
Definition
|
|
Term
| The exchange current density is defined when... |
|
Definition
| the anodic and cathodic currents have equal magnitude |
|
|
Term
| When the exchange current density is 10^-15 A/cm2 the electrochemical reaction is electrochemically reversible/irreversible |
|
Definition
|
|
Term
| Find the concentration overpotential of the proton reduction reaction, H+(aq) + e- = (1/2) H2(g), in PEMFC at temperature of 25 °C and current density of 0.4 A/cm2 if the limiting current density is 1.1 A/cm2 |
|
Definition
|
|
Term
| 16. Using Tafel equation calculate the cathodic current density for oxygen half reaction at 25 oC and ovepotential of 0.8 V if the exchange current density (jo) is 10^-7 A/cm2 and the transfer coefficient (α) is 0.3 |
|
Definition
|
|
Term
| Find total electrical efficiency of a fuel cell if current efficiency is 96%, voltage efficiency is 60%, and thermodynamic efficiency is 80% |
|
Definition
|
|
Term
| If the limiting current density of a fuel cell is 1 A/cm2, the operation current density should be above/below 1 A/cm2 |
|
Definition
|
|
Term
| As area specific resistance (Ri) increases, the fuel cell polarization curve shifts ___ |
|
Definition
|
|
Term
| In the Daniell cell lab, when the operational mode is changed from galvanic to electrolytic, electrode polarity is ___ |
|
Definition
|
|
Term
| For an electrolytic cell, magnitude of the applied voltage (potential difference) ___ magnitude of DP |
|
Definition
|
|
Term
| When a H2/O2 fuel cell operates at a potential difference (voltage) of 0.7 V and a current density of 0.5 A/cm2 , the power density is |
|
Definition
|
|
Term
| As exchange current density (io) increases, the fuel cell polarization curve shifts ___ |
|
Definition
|
|
Term
| As operating pressure (P) increases, the fuel cell polarization curve shifts ___ |
|
Definition
|
|
Term
| When in a H2/O2 fuel cell oxygen is replaced with air, the polarization curve shifts |
|
Definition
|
|
Term
| In the Daniell cell lab, when the operational mode is changed from galvanic to electrolytic, the cathode and anode ___ |
|
Definition
|
|
Term
| As transfer coefficient (alpha) increases, the fuel cell polarization curve shifts |
|
Definition
|
|
Term
| Calculate the charge passed through an alkaline electrolytic cell when a current of 1.8 A was constant during 3 hours |
|
Definition
|
|
Term
| When the amount of H2 produced in an electrolyzer is 2 L, the amount of O2 produced is ___ |
|
Definition
| H2:O2 production ratio is 2:1, so 1 L |
|
|
Term
| For a fuel cell, the operational voltage (potential difference) ___ OCP |
|
Definition
|
|
Term
| Find the mass of Cu dissolved during electrolysis in Daniell cell if the process takes 30 minutes at a constant current of 0.5 A |
|
Definition
| it's a very small amount, like ~0.3 g |
|
|
Term
| Thermodynamic efficiency of an H2/O2 FC at 1000 K and 1 bar is ___% |
|
Definition
|
|
Term
| Thermodynamic efficiency of an ideal heat engine is defined by ___ |
|
Definition
| the temp's of the hot and cold reserviors |
|
|
Term
| Thermodynamic efficiency of an ideal FC is defined by ___ and ___ |
|
Definition
Gibb's energy of rxn
enthalpy |
|
|
Term
| Thermodynamic efficiency of a C(s)/O2(g) FC that produces CO2(g) at 1000 K and 1 bar is ___ |
|
Definition
|
|
Term
| In a FC, DELTAG ___ DELTAH |
|
Definition
|
|
Term
| Find the standard entropy of the H2/O2 FC rxn at 400 K and 1 bar |
|
Definition
| !!!!!!!!!!!!!! -47.4 J/mol*K |
|
|
Term
| At 100 C and 1 bar, the standard electrode potential of H2(g)+0.5O2(g)=H2O(l) ___ that of H2(g)+0.5O2(g)=H2O(g) |
|
Definition
|
|
Term
| Find the standard Gibb's energy of a direct methanol fuel cell at STP (CH3OH(l)+1.5O2(g)=2H2O(l)+CO2(g)) |
|
Definition
| !!!!!!!!!!!! -702.3 kJ/mol |
|
|
Term
| Thermodynamic efficiency of a combined FC-HE system can be ___% |
|
Definition
|
|
Term
| Gibb's energy of a FC rxn should be ___ charged |
|
Definition
|
|
Term
| Gibb's energy of an electrolytic cell rxn should be ___ charged |
|
Definition
|
|
Term
| In PEMFC, the electrodes are separated by a ___-conductive membrane |
|
Definition
|
|
Term
| In PAFC the ionic conductivity is provided by ___ |
|
Definition
|
|
Term
| In PAFC the ion conducting electrolyte is ___ |
|
Definition
|
|
Term
| The common operating temperature of H2/O2 PEMFC is between ___ and ___ C |
|
Definition
|
|
Term
| The temperature range which is not covered in the fuel/electrolytic cell technologies is ___ to ___ C |
|
Definition
|
|
Term
| In DMFC the anode can be made from ___ |
|
Definition
|
|
Term
| In SOFC the ion conductivity is provided by ___ |
|
Definition
|
|
Term
| The MCFC anode is made from ___ |
|
Definition
|
|
Term
| The MCFC anode is made from ___ |
|
Definition
|
|
Term
| The operational temperature in MCFC is between ___ to ___ C |
|
Definition
|
|
Term
In AFC the ion-conducting electrolyte is
___ |
|
Definition
|
|
Term
|
Definition
|
|
Term
| The operational temperature in PAFC is around ___ C |
|
Definition
|
|
Term
| The Nernst equation for MCFC fueled by hydrogen is... |
|
Definition
| E = EØ + (RT/2/F) ln [pH2*(pO2)^0.5 * pCO2,c / pH2O(g) / pCO2,a] |
|
|
Term
| The membrane thickness in PEMFCs is usually around ___ |
|
Definition
|
|
Term
| Presently, the most promising fuel cells are ___ and ___ |
|
Definition
|
|
Term
| In PAFC the electrodes are made from ___ |
|
Definition
|
|
Term
| The operational temperature in SOFC is around ___ C |
|
Definition
|
|
Term
| In H2/O2 PEMFC the electrodes are made from ___ |
|
Definition
|
|
Term
| The SOFC anode is made from ___ |
|
Definition
|
|
Term
| The MCFC cathode is made from ___ |
|
Definition
|
|
Term
| In MCFC the ion conductor is... |
|
Definition
| ...a mixture of carbonates of alkali metals |
|
|
Term
| In MCFC the ion conductivity is provided by ___ |
|
Definition
|
|
Term
| The SOFC cathode is made from ___ |
|
Definition
|
|
Term
In SOFC the ion conductive membrane is
___ |
|
Definition
|
|
Term
| For the electrochemical reaction of reduction of oxygen in PEMFC at temperature below 100 °C ... |
|
Definition
| ...four-phase boundary problem should be considered |
|
|
Term
|
Definition
|
|
Term
| In PEMFC the gas diffusion layer is usually made from... |
|
Definition
| carbon cloth or carbon paper |
|
|
Term
| Catalysts in PEMFC are usually... |
|
Definition
| ...less Pt-loaded than in PEMEC |
|
|
Term
| Using available for you CRC data, calculate the standard electrode potential difference , Eo, of DMFC at temperature of 50 °C |
|
Definition
|
|
Term
| Using available for you CRC data, calculate the standard electrode potential difference, Eo, of DMFC at temperature of 150 °C |
|
Definition
|
|
Term
| SOFCs are ___ on the market |
|
Definition
|
|
Term
| In PEMFC the membrane electrode assembly (MEA) consists of... |
|
Definition
proton conductive membrane
two electrodes
two gas diffusion layers |
|
|
Term
| The main components of PEMFCs or PEMECs are... |
|
Definition
proton conductive membrane and two electrodes
gas diffusion layers and electron collector plates |
|
|
Term
| The typical material for PEM is ___ |
|
Definition
|
|
Term
| Using available for you CRC data, calculate the electrode potential difference, E, of SOFC which uses CO and air at temperature of 900 °C and pressure of 1 bar; pure CO is the SOFC input and pure CO2 is its output; the air oxygen is completely consumed in the SOFC |
|
Definition
|
|
Term
| In H2/O2 SOFC water is produced at the ___ |
|
Definition
|
|
Term
| The mane difference in polarization curve of PEMFC and SOFC is due to ___ |
|
Definition
| charge transfer polarization |
|
|
Term
| Using available for you CRC data, calculate the standard electrode potential difference, Eo, of CO/O2 SOFC at temperature of 900 °C and pressure of 1 bar |
|
Definition
|
|
Term
| Thermodynamic efficiency of a combined fuel cell and heat engine system is about ___% |
|
Definition
|
|
Term
| Conductivity of Nafion at room temperature is around ___ |
|
Definition
|
|
Term
| In PEMFC the bipolar plates can be made from... |
|
Definition
|
|
Term
| In H2/O2 PEMFC water is produced at the ___ |
|
Definition
|
|
Term
| Thermodynamic efficiency of a combined fuel cell and heat engine system ___ with temperature |
|
Definition
|
|
