1 / 7

Chemistry Report Guidelines and Practice Problems for Exam Review | Quiz 4 Returns and Enthalpy Examples

Get detailed formal report guidelines, Exam 2 review problems, and Quiz 4 statistics. Practice enthalpy examples and study combustion reactions. Understand enthalpy changes, standard states, and heat evolution in chemical reactions. Solve temperature and gas distribution problems. Attend class to benefit fully.

hermanharris
Télécharger la présentation

Chemistry Report Guidelines and Practice Problems for Exam Review | Quiz 4 Returns and Enthalpy Examples

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plan for Fri, 24 Oct 08 • Formal report guidelines • Quiz 4 returned • Exam 2 review problems • NOTE: I will not check my email on Sunday.

  2. Quiz 4 • Avg: 4.71 +/- 2.64 • High: 10, Low: 1 • You may re-work Prob. #1 only and turn it in Monday for full credit. • Please staple your new solution to the front of your quiz. • This option is only available to those who attend class Friday, Oct 24th.

  3. Which would you guess is in its standard state? • CO2(g) / CO2(s) • H2O(g) / H2O(l) / H2O(s) • N2(g) / N2(l) • Which of the following has DHfo = 0? • CO2(g) / H2O(l) / N2(g)

  4. Example Determine the standard enthalpy change at 25°C for the combustion of one mole of heptane (C7H16) sometimes used in gasoline fuel mixtures. The balanced equation is shown here: C7H16 (g) + 11 O2 (g)  7 CO2 (g) + 8 H2O (l) DHfo (kJ/mol) C7H16(g) -264 CO2(g) -394 H2O(l) -286 ANS: –4,800 kJ

  5. DH Stoichiometry Example • When sulfur (S8) burns in air, SO2 is produced. The reaction evolved 9.31 kJ of heat per gram of S8 at constant pressure. • Write the balanced chemical equation, including the appropriate enthalpy change. • How much heat is evolved when 15.0 g of S8 is burned? • 5.01 x 103 kJ of heat was evolved from the combustion of S8 in air. How many liters of SO2 were produced if the reaction occurred at 125oC and 0.879 atm?

  6. Cold water (35oC) 40. g Hot water (50oC) 10. g energy flow Lukewarm water T = ?? oC

  7. A A B B C C A B C D Same gas, different temperatures. Which of curves A, B, and C represents the highest temperature? the lowest? Same temperature, different gases. Curves A-D represent the speed distribution of He, Ne, Ar, and Xe gases at a certain temperature. Label each curve with the correct noble gas. = Xe(g) = Ar(g) = Ne(g) = He(g)

More Related