Answer:
a) ΔH°rxn = -9.2kJ/mol
b) ΔH°rxn = -9.2kJ/mol
Explanation:
Using Hess's law, you can find ΔH of a reaction from ΔH of formation of the substances involved in the reaction, thus:
ΔH°rxn = ∑(BE(reactants)) − ∑(BE(products))
Or:
ΔH°rxn = ∑(nΔH°f (products)) − ∑(mΔH°f (reactants))
For the reaction:
H₂(g) + I₂(g) → 2HI(g)
a) Using the first equation:
ΔH°rxn = ΔH (H-H) + ΔH (I-I) - 2ΔHBE (H-I)
ΔH°rxn = 436.4kJ + 151kJ - 2×298.3kJ
<em>ΔH°rxn = -9.2kJ/mol</em>
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b) Using the second equation:
ΔH°rxn = 2Δ°f (HI) − ΔH°f (H₂) - ΔH°f (I₂)
ΔH°rxn = 2×25.9kJ - 0kJ - 61.0kJ
<em>ΔH°rxn = -9.2kJ/mol</em>
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Answer:
The correct answer is 32.2 grams.
Explanation:
Based on the given information, the enthalpy of formation for aluminum oxide is 1676 kJ/mol. It signifies towards the energy that is required to generate aluminum and oxygen, and both of these exhibit zero enthalpy of formation. Therefore, the ΔHreaction is the required energy to generate 2 moles of aluminum. Thus, the energy needed for the formation of single mole of aluminum is,
ΔHrxn = 1676/2 = 838 kJ/mol
Q or the energy input mentioned in the given case is 1000 kJ. Therefore, the number of moles of Al generated is,
(1000 kJ) / (838 kJ/Al mole) = 1.19 moles of Aluminum
The grams of aluminum produced can be obtained by using the formula,
mass = moles * molecular mass
= 1.19 * 26.98
= 32.2 grams.
I would say C bc I don’t rlly think it’s A or B
Mn metal can be used as a sacrificial electrode to prevent the rusting of an iron pipe. So, the correct option is (c) Mn.
Commonly, sacrificial electrodes are employed to stop another metal from corroding or oxidising. A metal that is more reactive than the metal being shielded must serve as the sacrificial electrode. Magnesium, aluminium, and zinc are the three metals most frequently used in sacrificial anodes.
Manganese-Magnesium (Mn-Mg) electrode is more suited for on-shore pipelines where the electrolyte (soil or water) resistivity is higher since it has the highest negative electropotential of the three. In order to replenish any electrons that could have been lost during the oxidation of the shielded metal, the highly active metal offers its electrons.
Therefore, Mn metal can be used as a sacrificial electrode to prevent the rusting of an iron pipe. So, the correct option is (c) Mn.
Learn more about electrode here:
brainly.com/question/17060277
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