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aleksandr82 [10.1K]
3 years ago
11

Dry chemical hand warmers utilize the oxidation of iron to form iron oxide according to the following reaction: 4Fe(s)+3O2(g)→2F

e2O3(s) Standard thermodynamic quantities for selected substances at 25 ∘C Reactant or product ΔH∘f(kJ/mol) Fe(s) 0.0 O2(g) 0.0 Fe2O3(s) −824.2 Calculate ΔH∘rxn for this reaction.
Chemistry
1 answer:
Svetlanka [38]3 years ago
8 0

Answer:

-1648.4 kJ/mol

Explanation:

Based on Hess's law:

ΔHr = ∑n×ΔH°f(products) - ∑n×ΔH°f(reactants)

In the reaction:

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

ΔHr = 2 ΔH°f {Fe₂O₃} - (4ΔH°f {Fe(s)} + 3ΔH°f{O₂(g)}

As:

ΔH°f {Fe₂O₃} = -824.2kJ/mol

ΔH°f {Fe(s)} = 0.0kJ/mol

ΔH°f{O₂(g)} = 0.0kJ/mol.

Thus,

ΔHr = 2 ₓ -824.2kJ/mol =

<h3>-1648.4 kJ/mol</h3>
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The gas OF2 can be produced from the electrolysis of an aqueous solution of KF, as shown in the equation below.
Readme [11.4K]

Answer:

A) 6.48 g of OF₂ at the anode.

Explanation:

The gas OF₂ can be obtained through the oxidation of F⁻ (inverse reaction of the reduction presented). The standard potential of the oxidation is the opposite of the standard potential of the reduction.

H₂O(l) + 2 F⁻(aq) → OF₂(g) + 2 H⁺(aq) + 4 e⁻    E° = -2.15 V

Oxidation takes place in the anode.

We can establish the following relations:

  • 1 Faraday is the charge corresponding to 1 mole of e⁻.
  • 1 mole of OF₂ is produced when 4 moles of e⁻ circulate.
  • The molar mass of OF₂ is 54.0 g/mol.

The mass of OF₂ produced when 0.480 F pass through an aqueous KF solution is:

0.480F.\frac{1mole^{-} }{1F} .\frac{1molOF_{2}}{4mole^{-} } .\frac{54.0gOF_{2}}{1molOF_{2}} =6.48gOF_{2}

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3 years ago
02.04 Slide #2 Fill in the blanks based on the videos T Speed of reaction. When the of the reactants are moving too in a chemica
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3 years ago
Elvira Walks 4 miles to the west from school and stops at the store. She then walks 3 miles south.
dalvyx [7]

Answer:

distance = 7 miles

displacement = 5 miles

Explanation:

Distance is a scalar quantity as it takes account of magnitude traveled but not the direction traveled from starting point.

The distance traveled is the sum total of distances moved

distance = 4 + 3 = 7 miles

Displacement however, is a vector and measure the shortest possible distance traveled in a given direction from the starting point.

The path of Elvis' walking forms a right-angle triangle with the hypotenuse being the displacement and the other two sides being the distance traveled west and south.

Using Pythagoras' theorem; c² = a² + b²

where c = hypotenuse and a and b are the other two sides

c² = 4² + 3²

c² = 16 + 9 = 25

√c² = √25

c = 5

Therefore, displacement = 5 miles

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3 years ago
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When each of the following equilibria is disturbed by increasing the pressure as a result of decreasing the volume, does the num
NISA [10]

Answer:

1. CO(g) + H_2O(g)\rightleftharpoons CO_2(g) + H_2(g), remain the same.

2. 2CO(g)\rightleftharpoons C(s) + CO_2(g),increase.

3. N_2O_4(g)\rightleftharpoons 2NO_2(g), decrease.

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

Increase the pressure

If the pressure of the container is increased, the volume will decrease according to Boyle's Law. Now, according to the Le-Chatlier's principle, the equilibrium will shift in the direction where decrease in pressure is taking place.

1. CO(g) + H_2O(g)\rightleftharpoons CO_2(g) + H_2(g)

On increasing the pressure ,the equilibrium will shift in direction where decrease in pressure is taking place,so reaction will shift in no direction because number of gaseous moles are same on both sides. Hence no increase in number of moles of products.

2. 2CO(g)\rightleftharpoons C(s) + CO_2(g)

On increasing the pressure ,the equilibrium will shift in direction where decrease in pressure is taking place,so reaction will shift in forward direction because number of gaseous moles are less on product sides. Hence ,increase in number of moles of products.

3. N_2O_4(g)\rightleftharpoons 2NO_2(g)

On increasing the pressure ,the equilibrium will shift in direction where decrease in pressure is taking place,so reaction will shift in backward direction because number of gaseous moles are less on reactant side both sides. Hence, decrease in number of moles of products.

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3 years ago
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