ch302 - Mitchell, Viviane – Homework 1 – Due: Sep 11...

This preview shows pages 1–3. Sign up to view the full content.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Mitchell, Viviane – Homework 1 – Due: Sep 11 2007, 11:00 am – Inst: James Holcombe 1 This print-out should have 31 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points The vapor pressure of CH 3 COCH 3 (propa- none or acetone), is 67 Torr at 0 ◦ C and 222 Torr at 25 ◦ C. What is the normal boiling point of propanone? The universal gas con- stant is 8 . 314 J K · mol . Correct answer: 55 . 941 ◦ C. Explanation: T 1 = 0 ◦ C + 273 . 15 = 273 . 15 K T 2 = 25 ◦ C + 273 . 15 = 298 . 15 K P 1 = 67 Torr P 2 = 222 Torr P = 1 atm = 760 Torr R = 8 . 314 J K · mol Using the Clausius-Clapeyron equation, ln µ P 1 P 2 ¶ = Δ H ◦ vap R µ 1 T 2- 1 T 1 ¶ R ln µ P 1 P 2 ¶ 1 T 2- 1 T 1 = Δ H ◦ vap Δ H ◦ vap = ( 8 . 314 J K · mol ) ln µ 67 Torr 222 Torr ¶ 1 298 . 15 K- 1 273 . 15 K = 32445 . 7 J / mol . Applying the Clausius-Clapeyron equation again, ln µ P P 2 ¶ = Δ H ◦ vap R µ 1 T 2- 1 T ¶ R Δ H ◦ vap ln µ P P 2 ¶ = 1 T 2- 1 T 1 T = 1 T 2- R Δ H ◦ vap ln µ P P 2 ¶ = 1 298 . 15 K- 8 . 314 J K · mol 32445 . 7 J / mol ln µ 760 Torr 222 Torr ¶ = 0 . 00303867 ◦ C T = 1 . 00303867 ◦ C = 329 . 091 ◦ C- 273 . 15 = 55 . 941 K 002 (part 1 of 1) 10 points Arsine (AsH 3 ) is a highly toxic compound used in the electronic industry for the pro- duction of semiconductor. Its vapor pressure is 35 Torr at- 111 . 95 ◦ C and 253 Torr at- 83 . 6 ◦ C. What is the standard enthalpy of vaporization of arsine? Correct answer: 17 . 7248 kJ / mol. Explanation: T 1 =- 111 . 95 ◦ C + 273 . 15 = 161 . 2 K P 1 = 35 Torr P 2 = 253 Torr T 2 =- 83 . 6 ◦ C + 273 . 15 = 189 . 55 K P = 1 atm = 760 Torr Using the Clausius-Clapeyron equation, ln µ P 1 P 2 ¶ = Δ H ◦ vap R µ 1 T 2- 1 T 1 ¶ R ln µ P 1 P 2 ¶ 1 T 2- 1 T 1 = Δ H ◦ vap Δ H ◦ vap = ( 8 . 314 J K · mol ) ln µ 35 Torr 253 Torr ¶ 1 189 . 55 K- 1 161 . 2 K = 17724 . 8 J / mol = 17 . 7248 kJ / mol . 003 (part 1 of 1) 10 points The vapor pressure of CH 3 COCH 3 (propa- none or acetone), is 67 Torr at 0 ◦ C and 222 Torr at 25 ◦ C. What is the standard entropy of vaporization of propanone? Correct answer: 0 . 0985919 J K · mol . Explanation: T 1 = 0 ◦ C + 273 . 15 = 273 . 15 K Mitchell, Viviane – Homework 1 – Due: Sep 11 2007, 11:00 am – Inst: James Holcombe 2 P 1 = 67 Torr P 2 = 222 Torr T 2 = 25 ◦ C + 273 . 15 = 298 . 15 K P = 1 atm = 760 Torr Using the Clausius-Clapeyron equation, ln µ P 1 P 2 ¶ = Δ H ◦ vap R µ 1 T 2- 1 T 1 ¶ R ln µ P 1 P 2 ¶ 1 T 2- 1 T 1 = Δ H ◦ vap Δ H ◦ vap = ( 8 . 314 J K · mol ) ln µ 67 Torr 222 Torr ¶ 1 298 . 15 K- 1 273 . 15 K = 32445 . 7 J / mol ....
View Full Document

This note was uploaded on 06/16/2008 for the course CH 302 taught by Professor Holcombe during the Fall '07 term at University of Texas.

Page1 / 9

ch302 - Mitchell, Viviane – Homework 1 – Due: Sep 11...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online