## Search found 21 matches

Sat Mar 18, 2017 11:55 pm
Forum: *Alkenes
Topic: Z and E
Replies: 6
Views: 957

### Re: Z and E

Cis is when the substituents are on the same side of a double bond and trans is when they are on opposite sides. This should be apparent on the line structure just by looking at it. Z corresponds with cis and E corresponds with trans. You determine Z and E by looking at the atomic number (whichever ...
Sat Mar 18, 2017 11:05 pm
Forum: *Cycloalkenes
Topic: Question 6A on 2013 Final
Replies: 1
Views: 675

### Re: Question 6A on 2013 Final

The course reader answer has a 1 as the lowest number, while your proposed answer has a 2 as its lowest. Since 1<2, the course reader is correct. I think it's not necessarily about having overall lower numbers, it's just having THE lowest number.
Sat Mar 18, 2017 10:59 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Gauche vs Anti
Replies: 4
Views: 3909

### Re: Gauche vs Anti

Gauche is when the large atoms are staggered adjacent to each other (60 degrees) and anti is when the large atoms are opposite each other (180 degrees). Both are staggered but the names gauche and anti tell you the different energies of the conformations. Anti is the most stable (lowest energy) and ...
Sat Mar 18, 2017 10:54 pm
Forum: *Alcohols
Topic: Hydroxy vs Alcohol?
Replies: 2
Views: 811

### Re: Hydroxy vs Alcohol?

I think you use hydroxy when you are treating the -OH group as a substituent but you would only do this when there is more than one functional group. In 9B there was also a ketone in the first structure and a carboxylic acid in the second structure.
Wed Feb 22, 2017 6:44 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: HW #17 and #19
Replies: 2
Views: 380

### Re: HW #17 and #19

You can use any experiments; they are independent of each other.
Wed Feb 22, 2017 6:42 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: signs
Replies: 6
Views: 698

### Re: signs

If I am understanding your question correctly, I believe the negative sign is used when calculating the rate of the reactant because the concentration of the reactant decreases as it becomes product.
Wed Feb 22, 2017 10:38 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Questions about K on pg 73 of CR
Replies: 1
Views: 323

### Re: Questions about K on pg 73 of CR

You would select the first equation because it's the fast step. A buildup of the the intermediate causes the 1st step to be in equiilbrium. You need to use this first step to solve for the intermediate which you can then plug into the rate law for the slow step. I believe the 1/2 is because the coef...
Mon Jan 30, 2017 12:43 am
Forum: Administrative Questions and Class Announcements
Replies: 130
Views: 17217

### Re: Quiz 1 Preparation Answers

For #8, I don't understand why the reaction will not be spontaneous at any temperature. Please help! Thanks! If you plug in the given values into the equation deltaG= deltaH-T*deltaS and set delta G to zero, you will get a negative number for the temperature (-985.5K). You cannot have a temperature...
Thu Jan 26, 2017 11:36 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Quiz 1 Prep Question 3
Replies: 4
Views: 696

### Re: Quiz 1 Prep Question 3

I noticed Dr. Lavelle answered this question in another post. He just used the volumes and ignored the pressures given in the problem. The ratios of the pressures and the volumes should actually be the same, so you could use either V2/V1 or P1/P2 in the equation (since pressure and volume are invers...
Thu Jan 26, 2017 11:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Quiz 1 Preparation: Question 6
Replies: 4
Views: 592

### Re: Quiz 1 Preparation: Question 6

I'm also not completely sure, but I solved it the same way as Joseph.
Sun Jan 15, 2017 10:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Extensive property vs Intensive property [ENDORSED]
Replies: 1
Views: 417

### Re: Extensive property vs Intensive property[ENDORSED]

Specific heat capacity and molar heat capacity are the heat required to raise the temperature of "1 gram" and "1 mole," respectively, by 1 degree Celsius. In contrast, heat capacity is the heat required to raise the temperature of "an object" by 1 degree Celsius. Dividi...
Sun Dec 04, 2016 1:24 pm
Forum: Properties of Light
Topic: Fall 2016 Midterm #2B
Replies: 1
Views: 401

### Re: Fall 2016 Midterm #2B

Yes and you would also have to convert kJ to J.
Sat Dec 03, 2016 5:05 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Calculating x at equilibrium
Replies: 2
Views: 372

### Re: Calculating x at equilibrium

I think my TA said that if the Ka value is 10^-5 or smaller then you can assume x is zero. So under that circumstance I'm pretty sure you would be safe making that assumption on the final.
Sat Dec 03, 2016 2:51 pm
Forum: Dipole Moments
Topic: How to determine polarity
Replies: 1
Views: 487

### Re: How to determine polarity

The basic idea is that atoms of different elements have different electronegativities and exert pulls of differing strengths on the electrons. In a bond, the less electronegative atom will have a partial positive charge while the other atom will be slightly negative. If two different elements are bo...
Sat Dec 03, 2016 2:32 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Chapter 13 #7a
Replies: 2
Views: 828

### Re: Chapter 13 #7a

The chemical equation is HSO4- + H2O double arrows H3O+ +SO42-. You just use one equation for each part of this question and calculate the pH using the Henderson-Hasselbalch equation for the various concentrations of acid and conjugate base.
Sat Dec 03, 2016 2:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Chapter 12 problem 79
Replies: 2
Views: 466

### Re: Chapter 12 problem 79

Sulfuric acid is polyprotic so there are two deprotonizations. The first time, H2SO4 is completely ionized into HSO4- and H3O+. Since the ionization is complete, the concentration of HSO4- is 0.15M and the concentration of H3O+ is 0.15M (same concentration as H2SO4). The next ionization is incomplet...
Sat Dec 03, 2016 2:09 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Chapter 13 #5
Replies: 1
Views: 640

### Re: Chapter 13 #5

I think you can use the Henderson-Hasselbalch for #5 (as in #7), but it would be easier to use an ice table because this question only asked for the concentration of hydronium ions instead of pH. This means if you use the H-H equation you will have to convert from pH to [H+] which is an additional s...
Fri Oct 28, 2016 1:20 pm
Forum: Lewis Structures
Topic: Formal Charge
Replies: 3
Views: 365

### Re: Formal Charge

When you are asked to give the formal charge for each atom within a Lewis structure, you just calculate that using the formal charge formula. You don't need to give an average. As for the second half of your question, the problem will probably indicate whether multiple Lewis structures (resonance) a...
Fri Oct 14, 2016 7:42 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 1
Views: 363

### Re: Ionization Energy

An element has multiple ionization energies in the sense that the first ionization energy is the energy it takes to remove the outermost electron (ex. from Na to Na+). Then the second ionization energy is the energy it takes to remove another electron (Na+ to Na^2+), the third ionization energy is t...
Fri Oct 07, 2016 2:57 pm
Forum: Student Social/Study Group
Topic: Sunset Village Study Group
Replies: 17
Views: 1936

### Re: Sunset Village Study Group

I'm from Canyon Point A1 and I'd love to join sometimes! Is there a meeting place/time?
Fri Sep 30, 2016 1:33 pm
Forum: Significant Figures
Topic: Sig Figs. Problem
Replies: 4
Views: 794

### Re: Sig Figs. Problem

When making an intermediate calculation in a problem with multiple steps/operations, I usually underline the digit of the last sig fig but leave the number unrounded. It helps me to keep track of the number of sig figs from step to step without losing accuracy by rounding during intermediate steps.