Search found 21 matches

by Yusrah Ishtiaq 1E
Mon Mar 07, 2016 10:11 am
Forum: *Haloalkanes
Topic: Intro to Organic Chem (Self Test 2.2B)
Replies: 1
Views: 808

Intro to Organic Chem (Self Test 2.2B)

The following Self-Test Exercise 2.2B (A) says: "Name the compound (CH3)2CFCH2CH(CH2CH3)2." No matter how hard I try, I'm not getting the answer, which according to the solutions is: 4-Ethyl-2-fluoro-2methylhexane. Am I drawing the line structure wrong? Where is the F attached to and is it...
by Yusrah Ishtiaq 1E
Tue Mar 01, 2016 10:43 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Drawing Constitutional & Geometric Isomers
Replies: 1
Views: 345

Drawing Constitutional & Geometric Isomers

Is there a simple method of accurately drawing every possible constitutional and geometric isomer? I find that I'm having trouble drawing all the possible ones and always end up leaving some out. Is memorization pretty much the way to go for this? Or is there a better, more reliable approach?
by Yusrah Ishtiaq 1E
Sun Feb 28, 2016 1:01 pm
Forum: *Organic Reaction Mechanisms in General
Topic: Transition States in Reaction Mechanisms
Replies: 1
Views: 342

Transition States in Reaction Mechanisms

When you are asked to complete a reaction mechanism, do you also include the transition state with the partial bonds? Or unless explicitly stated (to include transition states), do you just draw the next step? Also, would we get points off if we forget to indicate the slight negative/positive charge...
by Yusrah Ishtiaq 1E
Mon Feb 15, 2016 1:28 pm
Forum: Second Order Reactions
Topic: Quiz Prep 2 Winter 2015 #10
Replies: 2
Views: 520

Re: Quiz Prep 2 Winter 2015 #10

It's a conceptual question! If you notice, the second concentrations they give you for both situations is half the initial concentration. So, they are testing you on if you're aware that the half-life of a second order reaction is dependent on initial concentration. Because the half-life is dependen...
by Yusrah Ishtiaq 1E
Sun Feb 14, 2016 5:02 pm
Forum: General Rate Laws
Topic: Homework 15.19
Replies: 1
Views: 420

Homework 15.19

I had a question about homework problem 15.9, Part C. It says: Determine the value of the rate constant. Given is a table with experiments one through five and their initial concentrations and initial rates. When I did this part, I ended up with 2.85 mmol/L*s . However, in the Solutions Manual, the ...
by Yusrah Ishtiaq 1E
Sun Feb 14, 2016 2:46 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: What does k' mean?
Replies: 1
Views: 418

Re: What does k' mean?

k' (kprime) is for the reverse reaction.
by Yusrah Ishtiaq 1E
Sat Feb 06, 2016 11:25 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Increasing Residual Entropy
Replies: 1
Views: 281

Increasing Residual Entropy

I had a question regarding residual entropy. I came across this problem in an old midterm: List the following compounds in order of increasing residual entropy. HF, C2H2, BCl2H The answer lists them as follows: BCl2H > HF > C2H2 I thought the more bonds a molecule has, the greater its entropy. So, w...
by Yusrah Ishtiaq 1E
Fri Jan 29, 2016 2:07 pm
Forum: Balancing Redox Reactions
Topic: Identifying Which Half-Reaction to Reverse
Replies: 3
Views: 499

Identifying Which Half-Reaction to Reverse

In lecture today, Professor Lavelle said that you reverse the half-reaction that, after you reverse, will cause you to get a positive value of voltage. So, does this mean the voltage always has to end up as a positive value?
by Yusrah Ishtiaq 1E
Sun Jan 24, 2016 10:09 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz #1
Replies: 3
Views: 562

Re: Quiz #1

On the Chem 14B website, Professor Lavelle posted this: Quiz 1 covers Chapter 8 and 9. In the course reader it is all material up to and including page 41.
by Yusrah Ishtiaq 1E
Sun Jan 17, 2016 12:04 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: degeneracy and energy
Replies: 2
Views: 309

Re: degeneracy and energy

According to the book, because a microstate only lasts for an instant , the energy of the microstates remains the same. In the book, it doesn't go into much detail as to why, but if you look it up online, it expands more on the idea. The detailed explanation is that "the total energy hasn't cha...
by Yusrah Ishtiaq 1E
Sat Jan 09, 2016 12:59 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry 14B Quiz #1
Replies: 1
Views: 463

Chemistry 14B Quiz #1

What chapters will Quiz #1 cover? I wanted to know ahead of time to plan out my studying. Thank you!
by Yusrah Ishtiaq 1E
Fri Dec 04, 2015 2:12 am
Forum: Lewis Acids & Bases
Topic: Increasing Strength of Acids (Electron Withdrawal Abilities)
Replies: 1
Views: 343

Increasing Strength of Acids (Electron Withdrawal Abilities)

Question number 7B on the Fall 2013 Final, asks to:

List the following acids in order of increasing strength and explain why.

A picture of the the four acids given are attached. Why is the acid with the F's the stronger than the acid with the Cl's attached to it?
by Yusrah Ishtiaq 1E
Sun Nov 29, 2015 2:34 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating a pH from a Concentration
Replies: 2
Views: 694

Calculating a pH from a Concentration

This is from the Self-Test 12.4A example in the textbook on page 473.

Calculate the pH of (a) household ammonia, in which the OH- concentration is about mol/L^-1; (b) M HClO4 (aq).

How do you calculate Part B?
by Yusrah Ishtiaq 1E
Sun Nov 22, 2015 4:37 pm
Forum: Bronsted Acids & Bases
Topic: J.5 Acid-Base Reactions
Replies: 1
Views: 476

J.5 Acid-Base Reactions

Fundamentals: J.5 Complete the overall equation and write the complete ionic equation and the net ionic equation for each of the following acid-base reactions. If the substance is a weak acid or base, leave it in its molecular form in the equations. b). (CH3)3N (aq) + HNO3 (aq) --> Completed equatio...
by Yusrah Ishtiaq 1E
Sat Nov 14, 2015 3:15 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining if a Ligand is Polydentate
Replies: 6
Views: 1231

Re: Determining if a Ligand is Polydentate

So, as long as two or more atoms have lone pairs, it’s going to be polydentate? How do you know if it’s bidentate or tridentate? The number of atoms with lone pairs?
by Yusrah Ishtiaq 1E
Sat Nov 07, 2015 10:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Reactions Reaching Equilibrium
Replies: 1
Views: 231

Chemical Reactions Reaching Equilibrium

Just out of curiosity, does every chemical reaction eventually reach equilibrium? If not, why? It is honestly pretty fascinating how everything in chemistry comes back to some kind of "ground state."
by Yusrah Ishtiaq 1E
Sat Oct 31, 2015 2:24 pm
Forum: Bond Lengths & Energies
Topic: Calculating Bond Order (Bonding & Antibonding Values)
Replies: 1
Views: 480

Calculating Bond Order (Bonding & Antibonding Values)

I'm confused on how to calculate bond order. I know the formula is 1/2(Number of Bonding Electrons - Number of Antibonding Electrons). However, I don't know how to use the Molecular Orbital diagram to find these two values, in the parentheses. I get confused on what to include and what not to includ...
by Yusrah Ishtiaq 1E
Sun Oct 25, 2015 1:38 pm
Forum: Lewis Structures
Topic: Element Arrangements & Lone Pairs
Replies: 1
Views: 309

Element Arrangements & Lone Pairs

Do lone pairs in a Lewis structure affect the arrangement of the elements? For example, for XeF4, does the Lewis structure have to be drawn like the one shown in the Solutions Manual or can it also be drawn like the picture I attached? Are both Lewis structures correct?
by Yusrah Ishtiaq 1E
Fri Oct 16, 2015 5:23 pm
Forum: Lewis Structures
Topic: Drawing & Determining Correct Lewis Structure
Replies: 4
Views: 642

Drawing & Determining Correct Lewis Structure

When you draw a Lewis Structure for a molecule and it has more than one correct structure, how do you know which one is the most stable? Also, is there a way to check if the structure is the best one, (are there specific characteristics it should have)?
by Yusrah Ishtiaq 1E
Sun Oct 11, 2015 12:02 pm
Forum: Ionic & Covalent Bonds
Topic: Valence Shells
Replies: 3
Views: 511

Re: Valence Shells

It is known that metals tend to lose electrons in reactions. In this case, Lithium has one valence electron. It would be far easier for it to lose its outermost electron, versus gain seven to achieve a full valence shell. In addition, Lithium has a low ionization energy compared to a nonmetal. There...
by Yusrah Ishtiaq 1E
Sat Oct 03, 2015 4:45 pm
Forum: Properties of Light
Topic: Rest Mass of Photons
Replies: 1
Views: 384

Rest Mass of Photons

I don't understand one thing about photons. How do photons have no rest mass, but have momentum and energy? Is it because they move at the speed of light?

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