Search found 13 matches

by Selena_Wong_1I
Sun Mar 19, 2017 8:20 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 200
Views: 45716

Re: Saying Thank You to Dr. Lavelle

Hi Dr. Lavelle,

Thanks for dedicating so much passion and time in teaching us Chem 14B. You really made my winter quarter memorable. I really enjoyed Friday's jokes and the numerous resources available for students.
by Selena_Wong_1I
Sun Mar 12, 2017 8:49 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Dihedral Angle
Replies: 1
Views: 265

Dihedral Angle

I am having difficulty seeing what the dihedral angle is?
by Selena_Wong_1I
Sun Mar 05, 2017 4:46 pm
Forum: *Electrophilic Addition
Topic: Reaction Profiles
Replies: 2
Views: 384

Reaction Profiles

Why is it that in transition states and intermediates, the energy is higher than in reactants and products?
by Selena_Wong_1I
Sun Feb 26, 2017 2:49 pm
Forum: *Nucleophiles
Topic: Basic Mechanisms
Replies: 1
Views: 184

Basic Mechanisms

When writing basic mechanisms, why do we draw the arrows from the nucleophiles to the electrophiles?
by Selena_Wong_1I
Sun Feb 19, 2017 4:33 am
Forum: First Order Reactions
Topic: Half Life
Replies: 1
Views: 270

Half Life

Why is the half-life of a first order reaction independent of the initial concentration?
by Selena_Wong_1I
Mon Feb 06, 2017 11:30 am
Forum: Balancing Redox Reactions
Topic: 14.11 (d)
Replies: 1
Views: 228

14.11 (d)

Write the half-reactions and the balanced equation for the cell reaction for each of the following galvanic cells: (d) Pt(s)|O2(g)|H+(aq)||OH-(aq)|O2(g)|Pt(s) If you look at the solution manual, why is the anode reaction the one with the larger Eknot? I thought the cell potential had to be positiv...
by Selena_Wong_1I
Sun Feb 05, 2017 3:52 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Standard Potentials in Electrochemical Series
Replies: 1
Views: 149

Standard Potentials in Electrochemical Series

Why is it more strongly reducing when the standard potential is low/negative and vice versa?
by Selena_Wong_1I
Thu Jan 26, 2017 8:56 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Self Test 9.17A
Replies: 1
Views: 223

Self Test 9.17A

Determine delta S,delta Ssurr, and delta Stot for (a) the reversible, isothermal expansion and (b) the isothermal free expansion of 1.00 mol of ideal gas molecules from 10.00 atm and 0.200 L to 1.00 atm and 2.00 L at 298 K. Why can we disregard the pressures ( 10 atm and 1 atm) when solving this ...
by Selena_Wong_1I
Sun Jan 22, 2017 11:20 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Example 8.7 on Section 8.13
Replies: 1
Views: 185

Re: Example 8.7 on Section 8.13

Normally, the equation of delta H = q/n. The enthalpy change is usually referred to as the the enthalpy change PER mole. However, in this question, the moles of C6H6 is 2, not 1. Therefore, we must multiply 2 * q/n.
by Selena_Wong_1I
Sat Jan 21, 2017 9:48 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.41
Replies: 2
Views: 313

Re: Homework Problem 8.41

At 0 degrees Celsius, there is a phase change because it has a mixture of ice and water. Therefore we must add that to the temperature change at 0 Celsius.
by Selena_Wong_1I
Sat Jan 21, 2017 9:29 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework chapter 8 #3 part a
Replies: 1
Views: 155

Re: Homework chapter 8 #3 part a

The volume of an object is length * width * height. In this particular case, we are trying to find the volume of a cylinder shaped object. The length * width portion of the volume is the cross section area of the cylinder, which is just the area of a circle (pir^2). We are given the diameter (3 cm),...
by Selena_Wong_1I
Sat Jan 21, 2017 9:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Question: 8.49
Replies: 1
Views: 232

Re: Homework Question: 8.49

The equation is delta U= q + w.
q= -318
w= -2.48
So the book is correct; you add q+w together to get -320 ( you subtracted w from q).
by Selena_Wong_1I
Sat Jan 14, 2017 3:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hw 8.75b
Replies: 1
Views: 170

Hw 8.75b

8.75 Use the bond enthalpies in Tables 8.6 and 8.7 to estimate the reaction enthalpy for (a) N2(g)+  3 F2(g) --> 2 NF3(g) (b) CH3CHCH2(g) + H2O(g) --> CH3CH(OH)CH3(g) (c) CH4(g)+  Cl2(g) -->CH3Cl(g)+  HCl(g) How am I supposed to know which mean bond enthalpies to use for CH3CHCH2 and CH3CH(OH)CH3?

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