Question

Calculate AH° for each of the following reactions, which occur in the atmosphere. (a) C2H4(g) + O3(g) → CH3CHO(g) + O2(g) СkJ (b) 03(g) + NO(g) → NO2(g) + O2(g) (c) SO3(g) + H20(1) - H2SO4(aq) Гk) (d) 2 NO(g) + O2(g) → 2 NO2(g) k]

Answer 1

Following is the - complete Answer -&- Explanation: for the given: Question: in...typed format...

$\Rightarrow$Answer:

1. part - (a): $\Delta$ H^o_rxn. = - 366.0 kJ / mol
2. part - (b):    $\Delta$ H^o_rxn. =  - 200.09 kJ / mol
3. part - (c):    $\Delta$ H^o_rxn. =  - 132.5 kJ / mol
4. part - (d): $\Delta$ H^o_rxn. =  - 114.18 kJ / mol

$\Rightarrow$Explanation:

Following is the complete : Explanation: for the above: Answer...

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$\Rightarrow$Part - (a):

• Given:

1. balanced chemical equation: C₂H₄ (g) + O₃ (g)  $\rightleftharpoons$ CH₃CHO (g) + O₂ (g) -------------Equation - 1

• ​​​​​​​Step - 1:

​​​​​​​Now, we know the following standard enthalpy of formation: of the given: reactants and products:

1. $\Delta$H_f^o [ C₂H₄ (g) ] = + 52.3 kJ / mol
2. $\Delta$H_f^o [ O₃ (g) ] = + 143.0 kJ / mol
3. $\Delta$H_f^o [ CH₃CHO(g) ] = -170.7  kJ / mol
4. $\Delta$H_f^o [O₂(g) ] = 0.0 kJ / mol

• ​​​​​​​Step - 2:

​​​​​​​Therefore, according to Equation - 1: the value of the standard change of enthalpy: of Equation - 1, will be the following;

$\Rightarrow$$\Delta$H^o_rxn. = [ ( 1.0 mol ) x ( $\Delta$ H_f^o [ CH₃CHO(g)) ] ) + (1.0 mol ) x ($\Delta$H_f^o [O₂(g) ] ) ] - [ ( $\Delta$ H_f^o[ C₂H₄ (g) ] + $\Delta$ H_f^o[ O₃ (g) ) ]

$\Rightarrow$ $\Delta$ H^o_rxn. = [ ( 1.0 mol ) x (-170.7  kJ / mol ) ] ) + (1.0 mol ) x (0.0 kJ/mol ) ] - [ ( 1.0 mol) x (52.3 kJ / mol ] + (1.0 mol ) x ( 143.0 kJ / mol ) ] = - 366.0 kJ / mol

$\Rightarrow$ $\Delta$ H^o_rxn. = - 366.0 kJ / mol

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$\Rightarrow$Part - (b):

• Given:

1. ​​​​​​​balanced chemical equation: O₃ (g) + NO (g)  $\rightleftharpoons$ NO₂ (g) + O₂ (g) -------------Equation - 2

• ​​​​​​​Step - 1:

​​​​​​​Now, we know the following standard enthalpy of formation: of the given: reactants and products:

1. $\Delta$H_f^o [ NO₂ (g) ] = + 33.2 kJ / mol
2. $\Delta$H_f^o [ O₃ (g) ] = + 143.0 kJ / mol
3. $\Delta$H_f^o [NO(g) ] = +90.29 kJ / mol
4. $\Delta$H_f^o [O₂(g) ] = 0.0 kJ / mol

• ​​​​​​​Step - 2:

​​​​​​​Therefore, according to Equation - 1: the value of the standard change of enthalpy: of Equation - 1, will be the following;

$\Rightarrow$$\Delta$H^o_rxn. = [ ( 1.0 mol ) x ( $\Delta$ H_f^o [ NO₂(g)) ] ) + (1.0 mol ) x ($\Delta$H_f^o [O₂(g) ] ) ] - [ ( $\Delta$ H_f^o[ O₃ (g) ] + $\Delta$ H_f^o[ NO(g) ) ]

$\Rightarrow$ $\Delta$ H^o_rxn. = [ ( 1.0 mol ) x (+ 33.2 kJ / mol ) ] ) + (1.0 mol ) x (0.0 kJ/mol ) ] - [ ( 1.0 mol) x (+ 143.0 kJ / mol   ] + (1.0 mol ) x ( +90.29 kJ / mol ) ] = - 200.09 kJ / mol

$\Rightarrow$ $\Delta$ H^o_rxn. = - 200.09 kJ / mol

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$\Rightarrow$Part - (c):

• Given:

1. ​​​​​​​balanced chemical equation: SO₃ (g) + H₂O (l)  $\rightleftharpoons$ H₂SO₄ (aq) -------------Equation - 3

• ​​​​​​​Step - 1:

​​​​​​​Now, we know the following standard enthalpy of formation: of the given: reactants and products:

1. $\Delta$H_f^o [H₂SO₄ (aq) ] = -814.0 kJ / mol
2. $\Delta$H_f^o [ SO₃ (g) ] = −395.7 kJ / mol
3. $\Delta$H_f^o [H₂O (l) ] = −285.8 kJ / mol

• ​​​​​​​Step - 2:

​​​​​​​Therefore, according to Equation - 1: the value of the standard change of enthalpy: of Equation - 1, will be the following;

$\Rightarrow$$\Delta$H^o_rxn. = [ ( 1.0 mol ) x ( $\Delta$ H_f^o [H₂SO₄ (aq) ] ) ] - [ ( $\Delta$ H_f^o[ SO₃ (g) ] + $\Delta$ H_f^o[ H₂O (l) ) ]

$\Rightarrow$ $\Delta$ H^o_rxn. = [ ( 1.0 mol ) x (-814.0 kJ / mol ) ] ) ] - [ ( 1.0 mol) x (−395.7 kJ / mol ) + (1.0 mol ) x (−285.8 kJ / mol ) ]

   = - 132.5 kJ / mol

$\Rightarrow$ $\Delta$ H^o_rxn. = - 132.5 kJ / mol

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$\Rightarrow$Part - (d):

• Given:

1. ​​​​​​​balanced chemical equation: 2 NO (g) + O₂ (g)  $\rightleftharpoons$ 2 NO₂ (g) -------------Equation - 3

• ​​​​​​​Step - 1:

​​​​​​​Now, we know the following standard enthalpy of formation: of the given: reactants and products:

1. $\Delta$H_f^o [ NO₂ (g) ] = + 33.2 kJ / mol
2. $\Delta$H_f^o [NO(g) ] = +90.29 kJ / mol
3. $\Delta$H_f^o [O₂(g) ] = 0.0 kJ / mol

• ​​​​​​​Step - 2:

​​​​​​​Therefore, according to Equation - 1: the value of the standard change of enthalpy: of Equation - 1, will be the following;

$\Rightarrow$$\Delta$H^o_rxn. = [ ( 2.0 mol ) x ( $\Delta$ H_f^o [NO₂ (g) ] ) ] - [ ( 2.0 mol ) x ( $\Delta$ H_f^o[ NO(g) ] + ( 1.0 mol ) x ($\Delta$H_f^o[ O₂ (g)) ]

$\Rightarrow$ $\Delta$ H^o_rxn. = [ ( 2.0 mol ) x (+ 33.2 kJ / mol ) ] ) ] - [ (2.0 mol) x (+90.29 kJ / mol ) + (1.0 mol ) x (0.0 kJ/mol) ]

   = - 114.18 kJ / mol

$\Rightarrow$ $\Delta$ H^o_rxn. = - 114.18 kJ / mol

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