Search found 10 matches

by Jerry Wang 1L
Fri Mar 17, 2017 11:45 pm
Forum: *Cycloalkanes
Topic: 1.16 in ochem book
Replies: 1
Views: 516

Re: 1.16 in ochem book

Both IUPAC and common naming are accepted according to Lavelle. Common naming is more convenient compared to IUPAC because it is shorter (as you will see in the following). For example, the strict IUPAC naming of the compound you have provided will be 1,1-dimethyl-2-(1-methylethyl)-cyclopentane. (Fe...
by Jerry Wang 1L
Thu Mar 09, 2017 1:53 am
Forum: *Alkanes
Topic: Naming [ENDORSED]
Replies: 92
Views: 8332

Re: Naming [ENDORSED]

You can think of Z as having the higher priority groups on the same side of the molecule (also known as "cis" and hence the mnemonic "Zee Zame Zide") and E as having the higher priority groups on the opposite sides of the molecule (also known as "trans"). When looking a...
by Jerry Wang 1L
Fri Mar 03, 2017 6:21 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: 4(36) Why z Gibbs Activation always + for reactions
Replies: 1
Views: 263

Re: 4(36) Why z Gibbs Activation always + for reactions

Hello, The Gibb's free energy is always going to be positive for the energy of activation because by definition, energy must be pumped into the system in order to overcome that energy barrier (or else it wouldn't be called energy of activation if it happened by itself!). Suppose that the Gibb's free...
by Jerry Wang 1L
Mon Feb 20, 2017 2:06 pm
Forum: Zero Order Reactions
Topic: Detail in the Rate Laws
Replies: 2
Views: 318

Re: Detail in the Rate Laws

The negative signs in equations must be observed. I would recommend you to go through the derivation process again to see how each one came about (because some of the kinetics equations don't have negative signs because of how the mathematics works out) but from the foundational equations such as d[...
by Jerry Wang 1L
Mon Feb 20, 2017 1:54 pm
Forum: Zero Order Reactions
Topic: Concept of Zero Order
Replies: 5
Views: 375

Re: Concept of Zero Order

A good example of 0 order is when the surface of a catalyst is saturated with the reactants (i.e all of its surface is covered by the reactant). Thus, no matter how much more you may increase the concentration of the reactants, the rate will still remain as k because those additional reactant molecu...
by Jerry Wang 1L
Fri Feb 10, 2017 12:18 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Qualitative ways to find Entropy
Replies: 3
Views: 401

Re: Qualitative ways to find Entropy

Firstly, you would rank by the complexity (i.e number of atoms) of the molecule. Those with higher complexities will have higher entropies. However, in this case, the molecules all have the same number of atoms. So, in order to arrange these molecules by entropies, we proceed to look at molar weight...
by Jerry Wang 1L
Fri Feb 03, 2017 10:47 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy
Replies: 2
Views: 353

Re: Entropy

Hi, To my knowledge, it is not possible to get entropy change from only the enthalpy change. Temperature must be known. If we look at the units, this is already telling because entropy is in J/K while enthalpy is in J (or kJ). q often is the enthalpy change, of which when we divide by temperature, w...
by Jerry Wang 1L
Tue Jan 24, 2017 5:37 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Ch. 8 Question 8.61 (Hess's Law)
Replies: 4
Views: 656

Re: Ch. 8 Question 8.61 (Hess's Law)

Hello Riley, Yes. We would use this approach if they ask you to use Hess's Law to find the enthalpy change associated with a reaction they want. In order to do this, the enthalpy change of the other reactions they want you to manipulate should be given (like how it was given in this problem). The en...
by Jerry Wang 1L
Tue Jan 17, 2017 2:30 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Ch. 8 Question 8.61 (Hess's Law)
Replies: 4
Views: 656

Re: Ch. 8 Question 8.61 (Hess's Law)

Hello, So this problem is dealing with Hess's Law, that is manipulating equations and their delta H's to give the desired chemical equation. There are multiple ways to think about this but I will lead you through mine. I recommend you to write it out on paper and follow each step because it is prett...
by Jerry Wang 1L
Wed Jan 11, 2017 10:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Chapter 8.55, Hess's Law
Replies: 4
Views: 429

Re: Chapter 8.55, Hess's Law

When we are multiplying the O2 reactant by 3/2 to balance this chemical reaction, there is no need to multiply the corresponding ΔH by 3/2. Balancing the equation is a separate idea from the multiplying the entire equation and its corresponding ΔH technique in Hess's Law problems.

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