Search found 25 matches

by Rita Tran 2B
Sun Mar 13, 2016 10:19 am
Forum: *Cyclohexanes (Chair, Boat, Geometric Isomers)
Topic: Most Stable Conformation - Larger Substituent
Replies: 2
Views: 407

Most Stable Conformation - Larger Substituent

When comparing which substituent is larger to put in the equatorial position of a cyclohexane, do you compare the total mass of the molecule or atomic number of first bonded atom? For example, between Br and ethyl, which one is considered larger to be put in the equatorial position to make the most ...
by Rita Tran 2B
Sat Mar 12, 2016 5:30 pm
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Tert and Sec Naming
Replies: 1
Views: 632

Tert and Sec Naming

When naming a compound using tert and sec, are we required to put them in parentheses since we cannot it italicize (how it is written in books and online) those terms when writing them? For example, is it 2-tert-butylpentane or 2-(tert)-butylpentane? Or are they both correct and it does not matter?
by Rita Tran 2B
Mon Feb 29, 2016 4:19 pm
Forum: *Cycloalkanes
Topic: Quiz 3 Preparation 1 Problem #5
Replies: 1
Views: 386

Quiz 3 Preparation 1 Problem #5

For the compound for question 5, what is the correct name: 1-bromo-3-iodocyclohexane or 3-bromo-1-iodocyclohexane (book answer)? I have been hearing different reasonings and answers, but I want to know which one is correct and why? When do you give iodo priority with the lower number? And why do you...
by Rita Tran 2B
Sun Feb 28, 2016 1:42 pm
Forum: *Alkanes
Topic: "Sum Rule"
Replies: 1
Views: 333

"Sum Rule"

I still do not quite understand why the "sum rule" does not always work. Can I get a few examples and explanations about why we should not use the "sum rule"?
by Rita Tran 2B
Mon Feb 15, 2016 9:52 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate Determining Step
Replies: 1
Views: 359

Rate Determining Step

Will the problems always state which step is fast and slow so that we could determine the rate determining step or do we have to some how figure it out based on the context given? If we have to figure it out, how do we know which step is fast and slow?
by Rita Tran 2B
Mon Feb 15, 2016 4:57 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Energetically Favorable
Replies: 1
Views: 436

Energetically Favorable

When looking at reaction profiles, how do you which reactions are energetically favorable? What does energetically favorable mean?
by Rita Tran 2B
Mon Feb 15, 2016 4:54 pm
Forum: General Rate Laws
Topic: Rate Law #7 (Quiz 2 Winter 2014)
Replies: 2
Views: 459

Re: Rate Law #7 (Quiz 2 Winter 2014)

So you just look for the rate determining step and find the order by looking at the coefficient?
by Rita Tran 2B
Mon Feb 15, 2016 4:06 pm
Forum: General Rate Laws
Topic: Rate Law #7 (Quiz 2 Winter 2014)
Replies: 2
Views: 459

Rate Law #7 (Quiz 2 Winter 2014)

For number 7 the question asks: "The following mechanism was proposed for the reaction: 2NO(g)+O_{2}\rightarrow 2NO_{2}(g) : Step 1(slow): NO+NO\rightarrow N_{2}O_{2} Step 2(fast): O_{2}+N_{2}O_{2}\rightarrow N_{2}O_{4} Step 3(fast): N_{2}O_{4}\rightarrow NO_{2}+NO_{2} What is t...
by Rita Tran 2B
Mon Feb 15, 2016 2:49 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Solving for K (Rate Constant)
Replies: 2
Views: 451

Solving for K (Rate Constant)

Since there are more than one experiment, which one are you suppose to chose when solving for the rate constant (k)? You get slightly different numbers when using different times and concentrations on the given tables. Is it best to always use the last time and concentration given?
by Rita Tran 2B
Tue Feb 09, 2016 9:44 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E as a Path Function
Replies: 1
Views: 386

E as a Path Function

If E is a path function, why is that we are allowed to do or be able to flip and add the E to calculate the total (similar to Hess's Law)?
by Rita Tran 2B
Sun Feb 07, 2016 2:32 pm
Forum: Balancing Redox Reactions
Topic: Half-Reactions (Midterm 2011 #6)
Replies: 1
Views: 368

Half-Reactions (Midterm 2011 #6)

Part A: When looking for the two half-reactions that would create a battery with the largest voltage, do you just look for the two largest positive and negative standard reduction potentials? Part B: After knowing that F_{2}/F^{-} and Rb^{+}/Rb would create the largest voltage, how do you know which...
by Rita Tran 2B
Wed Feb 03, 2016 5:33 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Question Regarding Favorable Processes
Replies: 1
Views: 323

Gibbs Free Energy Question Regarding Favorable Processes

On page 41 of the course reader where the Gibbs free energy is used to calculate the boiling point, I am confused as to why +\Delta H (endothermic) "does not favor the forward process". How can you determine this? I thought that according to the Le Châtelier's principle, endothermic reacti...
by Rita Tran 2B
Mon Jan 25, 2016 11:17 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Question #9 in Quiz 1 Winter 2015
Replies: 4
Views: 730

Re: Question #9 in Quiz 1 Winter 2015

Can someone explain why and are 0? How do you determine this value?
by Rita Tran 2B
Mon Jan 25, 2016 10:58 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Increase in Entropy (Quiz 1 #7 Winter 2015)
Replies: 1
Views: 1909

Increase in Entropy (Quiz 1 #7 Winter 2015)

Question number 7 states: Consider the following processes (treat all gases as ideal). 1) The pressure of 1 mole of oxygen gas is allowed to double isothermally. 2) Carbon dioxide is allowed to expand isothermally to 10 time its original volume. 3) The temperature of 1 mol of helium is increased 25 ...
by Rita Tran 2B
Mon Jan 25, 2016 6:13 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Quiz 1 Prep Winter 2014 #9
Replies: 5
Views: 741

Re: Quiz 1 Prep Winter 2014 #9

Dima, are we suppose to multiply 90.83 times 2 because there are 2 moles of HgO in the balanced equation and therefore get deltaH as +181.66? Also for deltaS, I got 216.6 J/Kmol. I did summationS (product) - summationS (reactants): (2(76.02)+205.14) - (2)(70.29). Are these steps correct even though ...
by Rita Tran 2B
Sun Jan 24, 2016 11:55 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isobaric (for Solids and Liquids)
Replies: 1
Views: 362

Isobaric (for Solids and Liquids)

For reactions with constant pressure that only involve solids and liquids, why and how is insignificant, which makes ?
by Rita Tran 2B
Sat Jan 23, 2016 1:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard State
Replies: 1
Views: 347

Standard State

How do you know if something is in its standard state or form? I am confused as to how to make sure everything is in its standard states. Will questions state that the element is in its standard state/form to know to use the standard reactant enthalpy equation?
by Rita Tran 2B
Sun Jan 17, 2016 11:25 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Entropy and Degeneracy
Replies: 1
Views: 420

Entropy and Degeneracy

Degeneracy is directly related to entropy, but what does that mean? What is the relationship and difference between entropy and degeneracy? Also, entropy is described as a property, but I am unclear as to what entropy is. Can I please get an explanation?
by Rita Tran 2B
Sat Jan 09, 2016 9:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Extensive and Intensive Properties
Replies: 1
Views: 474

Extensive and Intensive Properties

In the course reader it states that, "Heat capacity is an extensive property" and that "Specific heat capacity is an intensive property" (pages 5-6). What is an extensive property and an intensive property? I remembered from lecture that an extensive property is something like de...
by Rita Tran 2B
Tue Nov 24, 2015 3:57 pm
Forum: Quantum Numbers and The H-Atom
Topic: Video: Quantum Numbers
Replies: 1
Views: 367

Video: Quantum Numbers

Overview of Quantum Numbers

Chem Video.mp4 [ 257.41 MiB | Viewed 367 times ]

by Rita Tran 2B
Mon Oct 26, 2015 12:15 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond Order
Replies: 1
Views: 279

Bond Order

What are bond orders and how do you determine them? How can bond orders equal .5?
by Rita Tran 2B
Sun Oct 25, 2015 11:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H2CBr2 Polar and Dipole Moments
Replies: 1
Views: 328

H2CBr2 Polar and Dipole Moments

Is polar? If so, why is it polar because it seems as if the arrangement of the atoms could be symmetrical?
Also, can you explain how dipole moments cancel?
by Rita Tran 2B
Wed Oct 21, 2015 9:56 am
Forum: Ionic & Covalent Bonds
Topic: Electron Configurations of Copper (I) and Copper (II)
Replies: 2
Views: 13602

Electron Configurations of Copper (I) and Copper (II)

What are the electron configurations of:
(a) the copper(I) ion
(b) the copper(II) ion
(c) the manganese(II) ion
(d) the lead(IV) ion

What do the (I), (II), and (IV) mean and how do they change the electron configurations?
by Rita Tran 2B
Sat Oct 10, 2015 9:28 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7951
Views: 1212471

Re: Chemistry Jokes

Q: Where does a chemist put the dishes?
A: In the Zinc, of course!


Q: What did the thermometer say to the graduated cylinder?
A: "You may have graduated but I have many degrees!"


Q: Does light have mass?
A: Of course not! It's not even Catholic!!!
by Rita Tran 2B
Sun Oct 04, 2015 5:52 pm
Forum: Einstein Equation
Topic: Understanding Planck's Constant
Replies: 1
Views: 463

Understanding Planck's Constant

I know that Planck's Constant is J.s but how was this number derived and why is it used as "h" for the E=hv equation? What exactly is Planck's Constant?

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