Ex_3A_KEY.pdf

# Ch 3 ohg which choice below gives the correct signs

• 9
• 100% (1) 1 out of 1 people found this document helpful

This preview shows pages 5–8. Sign up to view the full content.

) ® CH 3 OH(g). Which choice below gives the correct signs for both ∆ H ° and ∆ S ° ? H ° S ° (A) + + (B) + (C) + (D) (3 pts) 15. A student performing a calorimetry experiment combined 100.0 mL of 0.50 M HCl and 100.0 mL of 0.50 M NaOH in a Styrofoam cup calorimeter. Both solutions were initially at 20.0 ° C, but when the two were mixed the temperature rose to 23.2 ° C. Is D H ° for the neutralization reaction between HCl and NaOH positive, negative, or zero? (A) positive (B) negative (C) zero (4 pts) 16. Suppose the experiment from #15 is repeated in the same calorimeter, but this time using 100 mL of 1.00 M HCl and 100.0 mL of 1.00 M NaOH. Will the D T observed be greater than, less than, or equal to that seen in the first experiment? (A) greater than (B) less than (C) equal to (6 pts) 17. Given the following data, N 2 (g) + O 2 (g) ® 2 NO(g) H ° = +181 kJ 2 NO(g) + O 2 (g) ® 2 NO 2 (g) H ° = –113 kJ 2 N 2 O(g) ® 2 N 2 (g) + O 2 (g) H ° = –163 kJ calculate D H ° for the reaction below. N 2 O(g) + NO 2 (g) ® 3NO(g) (A) 131 kJ (B) 65.5 kJ (C) –95 kJ (D) –78 kJ (E) 156 kJ

This preview has intentionally blurred sections. Sign up to view the full version.

A6 © 2018 L.S. Brown (15 pts) 18. Identify each of the following Lewis structures as correct or incorrect, and circle “correct” or “incorrect” under the structure. For each incorrect structure, draw the actual structure for the same molecule in the box provided. All of these are intended to be for neutral molecules (not ions), and the sequence of atoms for each is correct in the structure shown. At least one structure is correct, and at least one is incorrect. (Graded as 5 pts each. For the 2 you had to draw, that was 2 for saying “incorrect” and then 3 for the structure.) (a). NOF correct or incorrect (b). C 2 H 2 correct or incorrect (c). HCN correct or incorrect F N O H C C H C N H F N O H C C H
NAME:_________________________________ © 2018 L.S. Brown A7 19. Consider the complete combustion of octane, and use the thermodynamic data given as needed. 2 C 8 H 18 ( ! ) + 25 O 2 (g) ® 16 CO 2 (g) + 18 H 2 O( ! ) D H ° = –10,939.8 kJ Compound D H f ° (kJ/mol) S ° (J/K/mol) C 8 H 18 ( !

This preview has intentionally blurred sections. Sign up to view the full version.

This is the end of the preview. Sign up to access the rest of the document.
• Fall '07
• GENERALCHEMFORENG
• Chemistry, pts, Dr. Larry Brown, L.S. Brown

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern