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: Carbon
Explanation: Organic compounds are those made by carbon atoms that link to other carbon or elements such as nitrogen, hydrogen or oxygen with covalent bonds.
The presence of these compounds were associated with living things, because most of them are produced by plants or animals. However nowdays substances like polymers and other synthetically made molecules can also be considered as organic since they are made of carbon.
Hydrogen peroxide breaks down into oxygen and water. As a small amount of hydrogen peroxide generates a large volume of oxygen, the oxygen quickly pushes out of the container. The soapy water traps the oxygen, creating bubbles, and turns into foam.
The most common reaction that causes spoilage isn't a reaction at all. Molds and Bacteria are attracted to the easily found presence of water in the fruit. They find a natural place to reproduce and what they do causes spoilage.
Very few sources talk about the chemical changes that take place. If you put fruit in a refrigerator it slows the spoiling process down. That means that the chemical reaction has to be endothermic (it requires heat to occur)
The process of spoilage is speeded up by bananas for example, giving up Ethylene gas. You do not want to put a banana with tomatoes, because tomatoes are very sensitive to Ethylene. (It's OK to eat them together. They make a terrific salad. Yum).
I cannot find a definitive source that connects all this together, but the conduct of the fruit in refrigerators confirms what I am saying.
Spoilage is a very complex reaction and interaction with the environment. I have given you a hint of what happens but you should search it out to convince yourself of the outcome.
The answer would be C: energy is released to form radiation.