Hydroxyl radicals react with and eliminate many atmospheric pollutants. However, the hydroxyl radical does not clean up everything. For example, chlorofluorocarbons, which destroy stratospheric ozone, are not attacked by the hydroxyl radical. Consider the hypothetical reaction by which the hydroxyl radical might react with a chlorofluorocarbon: OH(g)+CF2Cl2(g)→HOF(g)+CFCl2(g) Use bond energies to explain why this reaction is improbable. Calculate ΔHrxn of this reaction.

Answers 3

Find attachments for complete solution

answer img
answer img
answer img
answer img

The enthalpy change ΔHrxn of the given reaction is 295 kJ/mol

Consider the hypothetical reaction whereby hydroxyl radical reacts with Chlorofluorocarbon. The balanced chemical equation can be expressed as:

\mathbf{OH_{(g)}+ CF_2Cl_{2(g)} \to HOF_{(g)} + CFCl_{2(g)} }

In the above chemical equation, the chemical species participating in the reaction are:

  • O-H, C-F, C-Cl, and O-F

The bond energies of these chemical species are:

  • O-H bond = 458.9 kJ/mol
  • C-F bond = 485 kJ/mol
  • C-Cl bond = 385 kJ/mol
  • O-F bond = 190 kJ/mol

The ΔHrxn is the enthalpy change of the reaction and it can be expressed by using the formula:

\mathbf{\Delta H_{rxn} = \sum \ B.E (reactants) - \sum \ B.E (products)}

\mathbf{\Delta H_{rxn} =\Big ( B.E (O-H) + 2B.E(C-F) +2B.E(C-Cl) \Big) - \Big( B.E (O-H) + B.E(O-F) } \\ \\ \mathbf{\ \ \ \ \ \ \ \ \ \ \ \ \ \ +B.E( C-F )+2B.E(C-Cl) \Big)}

By replacing the bond energies into the above expression, we have:

\mathbf{\Delta H_{rxn} =\Big ( 458.9 \ kJ/mol + 2(485 \ kJ/mol) +2(385 \ kJ/mol) \Big)} \\ \\ \mathbf{ - \Big( 458.9 \ kJ/mol + 190 \ kJ/mol +485 \ kJ/mol +2(385 \ kJ/mol)\Big)}

\mathbf{\Delta H_{rxn} =\Big ( 2198.9 \ kJ/mol \Big) - \Big( 1903.9\ kJ/mol\Big)}}

\mathbf{\Delta H_{rxn} =295 \ kJ/mol}

Therefore, provided that the enthalpy change is positive, it implies that the reaction is improbable and non-favorable.

AI generated Answer

ΔHrxn = -184.8 kJ/mol The hydroxyl radical reaction with chlorofluorocarbon is improbable because it requires energy to break the strong bonds of the reactants and form new bonds in the products. The C-F and Cl-Cl bonds have strong bond energies, whereas the O-F and C-Cl bonds have relatively weak bond energies. The difference in bond energies is greater than the amount of energy available in this reaction (-184.8 kJ/mol). Thus, the reaction is not thermodynamically favorable and is unlikely to occur under normal conditions.
  • Rate an answer:

Do you know an answer? Add it here!

Can't find the answer?

Unable to find an answer to your question?

Don't worry! There are several alternative approaches you can try to resolve your query. Here are some tips to help you find answers in different ways:

  1. Reframe your question: Sometimes, the way you phrase your question can limit your search results. Try rephrasing it using different keywords or providing more context to get better results.
  2. Utilize social media: Post your question on social media platforms, particularly those focused on professional or specialized topics. Twitter, LinkedIn, and Facebook groups can connect you with individuals who may have relevant expertise or experiences to share.
  3. Consult subject matter experts: Reach out to experts in the field related to your question. Many professionals are willing to help and share their knowledge. You can connect with them through email, LinkedIn messages, or by attending relevant conferences or events.
  4. Use our website to find your question through the search box above, or you can sign up to ask your question for our big educational community. Our experts will review your question, and you will get a quick and quality answer.
  5. Collaborate with others: If your question is related to a specific project or problem, consider collaborating with others who might have complementary skills or knowledge. Teamwork can lead to innovative solutions and shared insights.

Remember, the process of finding answers often involves persistence, creativity, and an open mind. By exploring various resources, reaching out to others, and being proactive in your search, you increase your chances of finding the information you need. Happy quest for knowledge!

Login with Google

or

Forgot your password?

I don't have an account, I want to Register

Choose a language and a region
How much to ban the user?
1 hour 1 day 100 years