Search found 20 matches

by Ashley_Thomas_3C
Sun Mar 19, 2017 3:34 am
Forum: Administrative Questions and Class Announcements
Topic: Quiz Solutions
Replies: 6
Views: 568

Re: Quiz Solutions

syun3c wrote:Are there solutions to the quizzes we took in class? Not the quiz preps.

nope, you'll have to search for some on chem community with key words. not all are there.
by Ashley_Thomas_3C
Thu Mar 16, 2017 8:59 pm
Forum: *Alkenes
Topic: Naming Convention for Double Bonds
Replies: 1
Views: 409

Re: Naming Convention for Double Bonds

Unless it's before the first carbon, you need to specify where it is.
by Ashley_Thomas_3C
Mon Mar 13, 2017 9:54 pm
Forum: General Science Questions
Topic: steric and torsional strain
Replies: 2
Views: 449

Re: steric and torsional strain

Torsional strain is the repulsion caused by the electrons in between different groups when they pass by each other, when rotating a molecule around a bond. So torsional strain can be thought as the repulsion due to electrostatic forces between electrons in adjacent molecular orbitals. On the other h...
by Ashley_Thomas_3C
Thu Mar 09, 2017 7:33 pm
Forum: *Cycloalkenes
Topic: 1.21 a b and c
Replies: 3
Views: 547

Re: 1.21 a b and c

You're not supposed to know how to do Q 1.21 for quiz 3 since Prof. Lavelle said we will not be quizzed on alkenes (carbon chains with a double bond). A diene is a hydrocarbon with two carbon double bonds.
by Ashley_Thomas_3C
Tue Mar 07, 2017 2:50 pm
Forum: *Alkenes
Topic: 1.25
Replies: 1
Views: 321

Re: 1.25

I think where you went wrong on this question is not taking into consideration the top right carbon group as part of the long chain when numbering.
by Ashley_Thomas_3C
Fri Mar 03, 2017 10:24 am
Forum: *Alkanes
Topic: Naming Example in Organic Textbook
Replies: 1
Views: 193

Re: Naming Example in Organic Textbook

We know that the second half of the chain (4,5,6,7 C) is not a substituent because if it were the substituent and the ethyl substituent were part of the chain, the chain would be a pentane - which wouldn't be the longest possible chain. Basically you try to configure the longest possible chain and t...
by Ashley_Thomas_3C
Tue Feb 28, 2017 8:37 pm
Forum: *Alkynes
Topic: Homework Problem 1.5 Part C Molecular Formula
Replies: 1
Views: 492

Re: Homework Problem 1.5 Part C Molecular Formula

The longer line in the middle is actually a single bond to the left of a triple bond, with a carbon in between the two bonds and on each end. Hopefully the image below will help you out!
by Ashley_Thomas_3C
Wed Feb 22, 2017 12:30 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Eq.
Replies: 1
Views: 194

Re: Arrhenius Eq.

Lowering the activation energy needed to start a reaction, often using a catalyst, increases the reaction rate. The reaction proceeds faster because less energy is required for molecules to react when they collide. Thus, the rate constant (k) increases.
by Ashley_Thomas_3C
Sun Feb 19, 2017 10:58 pm
Forum: General Rate Laws
Topic: Unique rate of reaction
Replies: 2
Views: 260

Re: Unique rate of reaction

The rate of reaction: 1. is change in concentration of a reactant or product per unit time 2. at any instant of time depends upon the molar concentrations of the reactants at that time 3. units are always mols The reaction rate constant: 1. is a constant of proportionality in the rate law equation a...
by Ashley_Thomas_3C
Sun Feb 19, 2017 10:53 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: k values
Replies: 1
Views: 193

Re: k values

The k value (rate constant of a chemical reaction) cannot be negative. If you think about it, a rate should never be negative since the rate is describing how fast the concentration changes with time.
by Ashley_Thomas_3C
Thu Feb 09, 2017 2:27 am
Forum: General Rate Laws
Topic: Orders
Replies: 1
Views: 236

Re: Orders

Changing the concentration of substances taking part in a reaction usually changes the rate of the reaction. A rate equation shows this effect mathematically. Orders of reaction are a part of the rate equation (the exponent). If the order of reaction with respect to A is 0 (zero), this means that th...
by Ashley_Thomas_3C
Sun Feb 05, 2017 10:43 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Bond Enthalpies
Replies: 7
Views: 512

Re: Bond Enthalpies

Entropies of large, complicated molecules are greater than those of smaller, simpler molecules because large, complicated molecules have more disorder as there are a greater number of ways they can move around in 3D space.
by Ashley_Thomas_3C
Mon Jan 30, 2017 3:18 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Question 9.1
Replies: 1
Views: 173

Re: Question 9.1

You basically use ∆S = q(rev)/T for the first and last part. For the second question you use the answer from the first question and convert it from seconds to days.
by Ashley_Thomas_3C
Mon Jan 30, 2017 10:17 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Bond Enthalpies
Replies: 7
Views: 512

Re: Bond Enthalpies

NO has a double bond while in NO2 the bonds are equivalent due to resonance. The lewis structures for NO and for NO2 show that the bond order in NO is the double bond and that in NO2 it is about the average of a N-O and N=O.
by Ashley_Thomas_3C
Sun Jan 29, 2017 10:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Entropy
Replies: 2
Views: 322

Re: Entropy

The latter is true - entropy is an extensive property. Entropy will increase as molar mass increases because the definition of entropy is the probability on how we can arrange molecules.
by Ashley_Thomas_3C
Thu Jan 26, 2017 1:27 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Questions
Replies: 1
Views: 193

Re: Gibbs Free Energy Questions

Gibbs free energy, G, which is defined as: ΔG= H-TΔS, is commonly known as the free energy and more formally as the Gibbs energy and is a thermodynamic function used to predict whether a reaction will be spontaneous in the forward or reverse direction (or whether it is at equilibrium). It is defined...
by Ashley_Thomas_3C
Mon Jan 23, 2017 5:54 pm
Forum: Administrative Questions and Class Announcements
Topic: Weekly Online Discussion
Replies: 6
Views: 770

Re: Weekly Online Discussion

Do you think it would still be accepted for the week if you're an hour or two late?
by Ashley_Thomas_3C
Mon Jan 23, 2017 4:29 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Bond Enthalpies of Diatomic Molecules
Replies: 1
Views: 200

Re: Bond Enthalpies of Diatomic Molecules

Table 8.6 lists bond enthalpies of only some diatomic molecules, not all. This is specified in the text next to the table.
by Ashley_Thomas_3C
Mon Jan 23, 2017 2:02 am
Forum: Phase Changes & Related Calculations
Topic: Open, Closed, and Isolated Systems
Replies: 8
Views: 634

Re: Open, Closed, and Isolated Systems

I think a constant pressure calorimeter is an isolated system because in order to measure the heat of a reaction, the reaction must be isolated so that no heat is lost to the environment. This is achieved by use of a calorimeter, which insulates the reaction to better contain heat. Coffee cups are o...
by Ashley_Thomas_3C
Fri Jan 13, 2017 10:20 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy Question
Replies: 4
Views: 325

Re: Standard Enthalpy Question

Essentially, enthalpy of formation refers to the change in enthalpy that takes place when a substance is formed from the most stable form of its elements. But in the case of natural elements in their most stable state, no change in enthalpy takes place because the reactants and the product are the s...

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