Question

Complete the stoichiometry of each reaction, making sure both stoichiometry and charge balance are correct. That is, find the values of the coefficients A, B, C, etc., for each reaction. Show your work and explain your reasoning. [2 Points each]

(a) Oxidation of nitrite to nitrate (a chemoautotrophic process): A·O2 + B·NO2- = C·NO3-

(b) Oxidation of organic matter using nitrite (a step of denitrification, a heterotrophic reaction):

A·CH2O + B·NO2- + C·H+ = D·CO2 + E·N2 + F·H2O
(c) Oxidation of ammonium with nitrite (anammox, a chemoautotrophic process):

A· NH4+ + B·NO2- = C·N2 + D·H2O

[Hint: start by writing the 2 half-reactions for each full reaction, including the number of electrons produced by the oxidation half-reaction, and the numbers of electrons required for the reduction half-reaction. Then balance H+ and H2O if required by stoichiometry, and sum the half reactions, each multiplied by the factor required to have the same number of electrons produced and consumed. End by simplifying terms present in both sides.]

Answer 1

Following is the - complete Answer -&- Explanation, for the given Question(s), in......typed format...

Answer:

1. part - (a): Coefficients ( desired ): A = 1.0; B = 2.0 ; C = 2.0   
2. part - (b): Coefficients ( desired ): A = 2.0; B = 2.0 ; C = 1.0 ; D = 2.0; E = 1.0 ; F = 2.0
3. part - (c):   Coefficients ( desired ): A = 1.0; B = 1.0 ; C = 1.0 ; D = 2.0

Explanation:

Following is the complete Explanation, for the above Answers...

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Following is the complete Answer -&- Explanation, for question: given in part - (a):

Part - (a):

Following is the complete balanced chemical equation: for the desired reaction:

O₂ (g) + 2 NO₂^- (g)    2 NO₃^- (g) ------------------------------------------------ Equation - 1

Where:

1. O₂ (g) = Gaseous Oxygen  
2. NO₂^- (g) = Nitrite ion
3. NO₃^- (g) = Nitrate ion
4. Coefficients ( desired ): A = 1.0; B = 2.0 ; C = 2.0   

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Following is the complete Answer -&- Explanation, for question: given in part - (b):

Part - (b):

Following is the complete balanced chemical equation: for the desired reaction:

2 CH₂O (aq) + 2 NO₂^- (g) + H⁺ (aq) 2 CO₂ (g) + N₂ (g) + 2 H₂O (l)  ------------------------- Equation - 2

Where:

1. CH₂O (aq) = Formaldehyde
2. NO₂^- (g) = Nitrite ion
3. H⁺ (aq)  = Hydrogen ion
4. CO₂ (g) = Carbon di-oxide
5. N₂ (g) = Nitrogen gas  
6. H₂O (l) =  Liquid water  
7. Coefficients ( desired ): A = 2.0; B = 2.0 ; C = 1.0 ; D = 2.0; E = 1.0 ; F = 2.0

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Following is the complete Answer -&- Explanation, for question: given in part - (c):

Part - (c):

Following is the complete balanced chemical equation: for the desired reaction:

NH₄⁺ (aq) +    NO₂^- (aq) N₂ (g) + 2H₂O (l) ------------------------------------------------ Equation - 1

Where:

1. NH₄⁺ (aq) = Ammonium ion ( cation )
2. NO₂^- (g) = Nitrite ion ( anion )
3. N₂ (g) = Nitrogen gas
4. H₂O (l) = Liquid Water
5. Coefficients ( desired ): A = 1.0; B = 1.0 ; C = 1.0 ; D = 2.0

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