Question

Burning H2 (g) in the presence of O2 (g) proceeds by the following reaction:                         H2...

Burning H2 (g) in the presence of O2 (g) proceeds by the following reaction:

                       

H2 (g) + ½ O2 (g) --> H2O (g)                       eq. 1

In a fuel cell, the oxidation half-reaction occurring at the anode (a solid conductor) is:

H2 (g) --> 2H+ (aq) + 2e- eq. 2

At the cathode (solid conductor), O2 is reduced:

O2 (g) + 4H+ (aq) + 4e- --> 2H2O (l) eq. 3

Using Hess’s Law, estimate the heat released by oxidizing 1.0 kg (495 mol) of H2 in a fuel cell. Note that the physical state of water is different in equations 1 and 3. The heat of vaporization () of water is 40.7 kJ/mol. Hint: Start by combining the half reactions and canceling species that appear on both sides.

A. 121.4 MJ
B. 660.0 J
C. 141.6 MJ
D. 161.7 MJ

Homework Answers

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Consider the half-cell reaction: O2(g) + 4H+ (aq) + 4e- → 2H2O If all the stoichiometric...
Consider the half-cell reaction: O2(g) + 4H+ (aq) + 4e- → 2H2O If all the stoichiometric coefficients are multiplied by a factor of 2, how are the following parameters changed (make sure to justify your answer): (a) the number of electrons (b) the reaction quotient (c) the standard Gibbs free energy (ΔG θ ) (d) the cell potential (E) (e) the standard cell potential (E θ )
For the following reactions and given standard reduction potentials O2(g) + 4H+(aq) + 2Cu(s)  2Cu2+(aq)...
For the following reactions and given standard reduction potentials O2(g) + 4H+(aq) + 2Cu(s)  2Cu2+(aq) + 2H2O(l) O2(g) + 4H+(aq) + 4e-  2H2O(l)       E° = 1.23 V Cu2+ + 2e-  Cu(s)    E° = 0.34 V a. Calculate E°cell b. Calculate ΔG° at 254 K
Given the following reactions and their enthalpies: ΔH(kJ/mol)−−−−−−−−−−− H2(g)⟶2H(g) +436 O2(g)⟶2O(g) +495 H2+12O2(g)⟶H2O(g) −242 Part A...
Given the following reactions and their enthalpies: ΔH(kJ/mol)−−−−−−−−−−− H2(g)⟶2H(g) +436 O2(g)⟶2O(g) +495 H2+12O2(g)⟶H2O(g) −242 Part A Devise a way to calculate ΔH for the reaction H2O(g)⟶2H(g)+O(g)
Given the following reactions and their enthalpies: ΔH(kJ/mol)−−−−−−−−−−− H2(g)⟶2H(g)   +436 O2(g)⟶2O(g)   +495 H2+1/2O2(g)⟶H2O(g)   −242 A. Devise...
Given the following reactions and their enthalpies: ΔH(kJ/mol)−−−−−−−−−−− H2(g)⟶2H(g)   +436 O2(g)⟶2O(g)   +495 H2+1/2O2(g)⟶H2O(g)   −242 A. Devise a way to calculate ΔH for the reaction H2O(g)⟶2H(g)+O(g) B. estimate the H-O bond energy
Consider a hydrogen-oxygen fuel cell, an electrochemical cell that generates electricity from the chemical reaction 2...
Consider a hydrogen-oxygen fuel cell, an electrochemical cell that generates electricity from the chemical reaction 2 H2(g) + O2(g) → 2 H2O(l) . Yes, this is the same reaction as in additional question 1, but now we are looking at electrochemical aspects of it. On one side of the cell, H2 is pumped in, and the half-cell reaction is 2 H2(g) + 4 OH–(aq) → 4 H2O(l) + 4 e– ; at the other side, O2 is pumped in: O2(g)...
COmbusting 44.8L of H2(g) with 22.4L of O2(g) (both at STP) results in the formation of...
COmbusting 44.8L of H2(g) with 22.4L of O2(g) (both at STP) results in the formation of 44.8L of H2O(g) if the reaction is maintained at the same condition (STP) and goes to completion. Given the heat of formation of water (delta Hf=-241.8 kJ/mol) calculate: a) the PV work b) the heat evolved c) the change in internal energy of the system and d) the change in internal energy of the surroundings.
Given the following thermochemical data: ½H2(g)+AgNO3(aq) → Ag(s)+HNO3(aq) ΔH = -105.0 kJ 2AgNO3(aq)+H2O(l) → 2HNO3(aq)+Ag2O(s) ΔH...
Given the following thermochemical data: ½H2(g)+AgNO3(aq) → Ag(s)+HNO3(aq) ΔH = -105.0 kJ 2AgNO3(aq)+H2O(l) → 2HNO3(aq)+Ag2O(s) ΔH = 44.8 kJ H2O(l) → H2(g)+½O2(g) ΔH = 285.8 kJ Use Hess’s Law to determine ΔH for the reaction: Ag2O(s) → 2Ag(s)+½O2(g)
Given the following information below, use Hess’s Law to calculate the enthalpy of formation for sodium...
Given the following information below, use Hess’s Law to calculate the enthalpy of formation for sodium oxide: Na (s)     +      HCl (l)  à    NaCl (aq) + ½ H2 (g)                ∆HRx = -393.1 kJ/mol Na2O (s)     +     2 HCl (l)  à 2 NaCl (aq)   + H2O              ∆HRx = -675.2 kJ/mol H2 (g)       +      ½ O2 (g)  à    H2O (g)                              ∆HRx = -288.1 kJ/mol 2 Na (s)       +       ½ O2 (g)   à   Na2O (s)                          ∆HRx =    __________ kJ/mol Calculated Heat of Reaction is....? (Put your answer in...
What is the value of ∆H for the reaction   H2(g)   +    ½ O2(g)→ H2O(l) at 100ºC...
What is the value of ∆H for the reaction   H2(g)   +    ½ O2(g)→ H2O(l) at 100ºC and 1 atm? The experimental values of the average molar heat capacity at constant pressure, Cp, over the range 25ºC to 100ºC are 28.9, 29.4, and 75.5 J/K -mole, for H2(g), O2(g) and H2O(l), respectively.
In the following reaction 2H2(g)   + O2(g) = 2H2O(l) a) write balanced oxidation half -reaction b) )...
In the following reaction 2H2(g)   + O2(g) = 2H2O(l) a) write balanced oxidation half -reaction b) ) write balanced reduction half-reaction c) identify the oxidizing agent d) identify the reducing agent