Search found 11 matches

by Celina N 2H
Mon Mar 20, 2017 4:22 pm
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Chair conformations [ENDORSED]
Replies: 2
Views: 1226

Re: Chair conformations [ENDORSED]

Looking at the top of Pg. 112, the one on the left is trans -1,4-dimethylcyclohexane. "Trans" means "opposite"; we can see that the two methyl substituents are on opposite sides of the cyclohexane ring. The one on the right is cis -1,4-dimethylcyclohexane. "Cis" means &...
by Celina N 2H
Mon Mar 13, 2017 11:42 pm
Forum: *Alkanes
Topic: Nomenclature
Replies: 3
Views: 439

Re: Nomenclature

It is probably safer (and more convenient!) to know them.

There is a considerable number of functional groups that include a carbon-oxygen double bond; this is called a carbonyl. A functional group that includes a carbon-nitrogen double bond is called an imine.
by Celina N 2H
Mon Mar 06, 2017 9:48 am
Forum: *Cycloalkanes
Topic: Geometric vs Constitutional Isomers [ENDORSED]
Replies: 2
Views: 490

Re: Geometric vs Constitutional Isomers [ENDORSED]

Constitutional isomers have atoms that vary in the order in which they are connected in; therefore, constitutional isomers may contain differing bonding patterns or functional groups. Geometric isomers are based on geometric configuration; they can vary in position around bonds with restricted rotat...
by Celina N 2H
Mon Feb 27, 2017 9:32 am
Forum: *Electrophiles
Topic: Showing Electron Arrangement
Replies: 1
Views: 245

Re: Showing Electron Arrangement

Yes, this is important, as which arrow you use gives the e - arrangement; as stated in the course reader, the arrows give more detail to an organic reaction mechanism. A "full triangle" at the tip of the arrow denotes a 2 e - rearrangement, while a "half triangle" at the tip of t...
by Celina N 2H
Mon Feb 20, 2017 1:04 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: determining stabililty
Replies: 1
Views: 234

Re: determining stabililty

A good example of how to determine stability can be found on Pg. 57 of our Course Reader. The graph on this page shows the reaction of diamond (reactant) --> graphite (product). We can see that diamond has a high potential energy; therefore, it is kinetically stable but thermodynamically unstable. O...
by Celina N 2H
Mon Feb 13, 2017 10:44 am
Forum: Balancing Redox Reactions
Topic: K and K(sub)a
Replies: 2
Views: 451

Re: K and K(sub)a

There is a good example of this in the Winter 2014 Midterm, Question 8, where you are asked to find the value of K A for HF using given standard cell potentials. Because we know that HF is a weak acid, we know that (1) it dissociates to H + (aq) and F - (aq), and (2) it has an acid dissociation cons...
by Celina N 2H
Mon Feb 06, 2017 9:37 am
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Rechargeable Batteries
Replies: 2
Views: 558

Re: Rechargeable Batteries This recent article introduces many new solutions to bulky and quick-dying batteries. This includes gold nanowire batteries (nanowires, a “thousand times thinner than human hair,...
by Celina N 2H
Mon Jan 30, 2017 10:27 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy
Replies: 5
Views: 625

Re: Entropy

Entropy is a state function that acts as a measurement of disorder. Thus, a positive entropy change correlates to greater disorder. Because the sum of the entropy change in the system and its surroundings must be positive for a reaction to be spontaneous, all spontaneous reactions occur through an i...
by Celina N 2H
Mon Jan 23, 2017 3:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Boltzmann equation
Replies: 1
Views: 324

Re: Boltzmann equation

The quantity W in the Boltzmann equation stands for the number of different ways that atoms in molecules in a sample can be arranged and yet each still amounting to the same total energy ( Chemical Principles: The Quest for Insight , 6th edition). Every different arrangement of the molecules in a sa...
by Celina N 2H
Mon Jan 16, 2017 11:37 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Question about R value
Replies: 1
Views: 370

Re: Question about R value

The value of R, referred to as the gas constant , has different numerical values based on the units it is expressed in. We can determine which R value to use by looking at the units of the other provided information from the problem; we should choose the R value that will cancel the proper units out...
by Celina N 2H
Thu Jan 12, 2017 3:13 pm
Forum: Phase Changes & Related Calculations
Topic: Bond Enthalpy and Enthalpy of Formation
Replies: 4
Views: 510

Re: Bond Enthalpy and Enthalpy of Formation

The enthalpy of formation of oxygen (O 2 ) is 0 because O 2 is the element oxygen in its most stable state. Therefore, elements in their most stable states (e.g., H 2 for hydrogen, F 2 for fluorine, C for carbon, etc.) all have enthalpy of formation equal to 0. In all other less stable forms, enthal...

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