A small sample of methane burns, releasing 120.0 kJ of heat and doing 830.0 kJ of work. The total energy released is -950.0 kJ.
Energy is a property that is transferred to a physical system, recognizable in the performance of work and in the form of heat and light.
A small sample of methane undergoes combustion. As the hot gas mixture expands, it releases energy (E).
- It releases 120.0 kJ of heat. By convention, when heat is released, we assign it a negative sign. Thus, q = -120.0 kJ.
- It does 830.0 kJ of work. By convention, when the system does work on the surroundings, we assign it a negative sign. Thus, w = -830.0 kJ.
The change in the energy is the sum of the heat released and the work done.
ΔE = q + w = -120.0 kJ + (-830.0 kJ) = -950.0 kJ
A small sample of methane burns, releasing 120.0 kJ of heat and doing 830.0 kJ of work. The total energy released is -950.0 kJ.
Learn more about energy here: brainly.com/question/13881533
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First, we write the half equations for the reduction of the chemical species present:
Cu⁺² + 2e → Cu; E° = 0.34 V
Ni⁺² + 2e → Ni; E° = - 0.23 V
In order to determine the potential of the cell, we find the difference between the two values. For this:
E(cell) = 0.34 - (-0.23)
E(cell) = 0.57 V
The second option is correct. (The difference in values is due to different values in literature, and it is negligible)
The reaction which shows oxidation and reduction simultaneously is C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(l).
<h3>What are redox reactions?</h3>
Those reaction in which oxidation as well as reduction of substances takes place simultaneously will known as redox reactions.
- SO₂(g) + H₂O(l) → H₂SO₃(aq)
- CaCO₃(aq) → CaO(s) + CO₂(g)
- Ca(OH)₂(s) + H₂CO₃(l) CaCO₃(aq) + 2H₂O(l)
Above reaction are not the redox reactions as in these reaction oxidation and reduction simultaneously not takes place.
- C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(l)
In the above reaction reduction of oxygen takes place as its oxidation state changes from 0 to -2, and at the same time oxidation of carbon takes place as its oxidation state changes from 0 to +4.
Hence correct option is (4).
To know more about redox reactions, visit the below link:
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Where are the answers that apply .. hopes this help :)
