Skip to main content
Ch.5 - Thermochemistry

Chapter 5, Problem 126

The methane molecule, CH4, has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is 'expanded,' by simultaneously extending all four C—H bonds to infinity. We then have the process CH41g2¡C1g2 + 4 H1g2 (a) Compare this process with the reverse of the reaction that represents the standard enthalpy of formation of CH41g2.

Verified Solution
Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
779
views
Was this helpful?

Video transcript

Hey everyone. So here we have the following adam Ization reaction. I'm hydrogen chloride. For the H. C. O bond is broken to produce H and cl atoms in the gas phase. They were as house this reaction similar or different from the reverse other standard entropy information of hydrogen chloride gas. So for the information we can have our elements and their standard states And it's gonna produce one mole of a substance. We're gonna have hydrogen in its standard site which is H2 gas Plus chlorine in its standard state which is cl two gas and it's gonna be one more with H. C. L. Yes, analysis balances. We have package in in the chlorine on both sides. We have two hydrogen over here to chlorine over here, one hydrogen here, one chlorine over here. Since we need to keep one mole of hydrogen chloride, We need to put one half in front of H2 and cl two. So for the reverse we're gonna have hcl yes, building one half H two yes plus one half cl two gas. So in an organization, the products are in atomic form in the reverse of the formation equation. The products are there standards form of the elements. So this is your answer. Thanks for watching my video and I hope it was helpful
Related Practice
Textbook Question
Consider the following acid-neutralization reactions involving the strong base NaOH(aq): HNO31aq2 + NaOH1aq2¡NaNO31aq2 + H2O1l2 HCl1aq2 + NaOH1aq2¡NaCl1aq2 + H2O1l2 NH4+1aq2 + NaOH1aq2¡NH31aq2 + Na+1aq2 + H2O1l2 (d) In the third equation NH4 +1aq2 is acting as an acid. Based on the value of H° for this reaction, do you think it is a strong or a weak acid? Explain.
738
views
Textbook Question

Consider two solutions, the first being 50.0 mL of 1.00 M CuSO4 and the second 50.0 mL of 2.00 M KOH. When the two solutions are mixed in a constant-pressure calorimeter, a precipitate forms and the temperature of the mixture rises from 21.5 to 27.7 °C. (a) Before mixing, how many grams of Cu are present in the solution of CuSO4?

980
views
Textbook Question
A sample of a hydrocarbon is combusted completely in O21g2 to produce 21.83 g CO21g2, 4.47 g H2O1g2, and 311 kJ of heat. (a) What is the mass of the hydrocarbon sample that was combusted?
718
views
Textbook Question
One of the best-selling light, or low-calorie, beers is 4.2% alcohol by volume and a 355-mL serving contains 110 Calories; remember: 1 Calorie = 1000 cal = 1 kcal. To estimate the percentage of Calories that comes from the alcohol, consider the following questions. (a) Write a balanced chemical equation for the reaction of ethanol, C2H5OH, with oxygen to make carbon dioxide and water. (b) Use enthalpies of formation in Appendix C to determine ΔH for this reaction. (c) If 4.2% of the total volume is ethanol and the density of ethanol is 0.789 g/mL, what mass of ethanol does a 355-mL serving of light beer contain? (d) How many Calories are released by the metabolism of ethanol, the reaction from part (a)? (e) What percentage of the 110 Calories comes from the ethanol?
662
views