Homework 1-solutions - devore (kd6877) Homework 1 vanden...

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

View Full Document Right Arrow Icon
devore (kd6877) – Homework 1 – vanden bout – (51640) 1 This print-out should have 24 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. All homework will be equally weighted re- gardless oF the number oF question on each assignment. 001 10.0 points Substance A has undergone a phase tran- sition (under constant pressure) where ΔH = 10kJ / mol and ΔS = 36J / K · mol. What phase transition could have occurred? 1. deposition 2. condensation 3. Freezing 4. melting correct Explanation: Melting is the only phase transition listed where both ΔH and ΔS are positive values. Condensation (gas to liquid), Freezing (liqid to solid) and deposition (gas to solid) all have a negative ΔH and ΔS. 002 10.0 points Rank the Following in order oF increasing va- por pressure at a fxed temperature: H 2 O, CH 3 Cl, He, NaCl 1. He < H 2 O < CH 3 Cl < NaCl 2. H 2 O < NaCl < CH 3 Cl < He 3. H 2 O < CH 3 Cl < He < NaCl 4. NaCl < CH 3 Cl < H 2 O < He 5. NaCl < H 2 O < CH 3 Cl < He correct Explanation: 003 10.0 points Answer the Following about CO 2 using the provided phase diagram. What answer choice best describes the tem- perature at the triple point and critical point For CO 2 (triple point temperature, critical point temperature)? Carbon Dioxide 3 1 4 2 200 250 300 350 400 10 0 10 1 10 2 10 3 10 4 Pressure, bar Temperature, K 1. 310 K, 310 K 2. 310 K, 220 K 3. 220 K, 310 K correct 4. Not enough inFormation 5. 220 K, 220 K Explanation: 004 10.0 points Which oF the Following constants are needed to calculate the change in enthalpy (ΔH) For heating a sample oF liquid water at 10 o C to steam at 150 o C. I) the heat capacity oF water II) the enthalpy oF Fusion oF water III) the heat capacity oF ice IV) the enthalpy oF vaporization oF water V) the heat capacity oF steam 1. I and V only 2. I, II, IV and V only 3. I, II, III, IV and V 4. I, II and III only
Background image of page 1

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

View Full DocumentRight Arrow Icon
devore (kd6877) – Homework 1 – vanden bout – (51640) 2 5. I and III only 6. I, IV and V only correct 7. II and III only Explanation: The heat capacity of water is necessary to calculate heat needed to raise the liquid wa- ter’s temperature from 10 o C to 100 o C. The enthalpy of vaporization of water is necessary to calculate the heat needed to convert 10 gram of water at 100 o C to 10 grams of steam at 100 o C. Finally, the heat capacity of steam is necessary to calculate heat needed to raise the steam’s temperature from 100 o C to 150 o C. 005 10.0 points When a chemical reaction comes to equilib- rium, both the forward and the reverse reac- tions continue, but their rates are equal. For such a system at equilibrium at 300 K and 1.00 atm pressure, the change in Gibbs free energy as the forward reaction occurs must be 1. negative. 2.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/09/2011 for the course CHEM 302 taught by Professor Mccord during the Spring '10 term at University of Texas at Austin.

Page1 / 7

Homework 1-solutions - devore (kd6877) Homework 1 vanden...

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

View Full Document Right Arrow Icon
Ask a homework question - tutors are online