## Search found 22 matches

Sat Mar 18, 2017 1:36 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Winter 2013 Final 1B
Replies: 4
Views: 497

### Re: Winter 2013 Final 1B

Why do we assume that the expansion and temperature change aren't simultaneous? My intuition is to assume that since volume expands from 3.0 to 3.5 liters, we wouldn't use the equation with constant volume but with constant pressure. Are these types of problems usually this way (where volume expands...
Sat Mar 18, 2017 1:03 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Winter 2013 Final 1B
Replies: 4
Views: 497

### Winter 2013 Final 1B

For question 1B, aren't you supposed to use Cp instead of Cv? In the answer, Cv is used but volume is not constant while temperature is. The variable in the subscript in these is supposed to be the variable held constant, right?
Fri Mar 17, 2017 2:53 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst that is used and produced
Replies: 4
Views: 483

### Re: Catalyst that is used and produced

veeksha25 wrote:Do you include the catalyst when writing the rate law?

Yes, because it affects the rate of the reaction.
Fri Mar 17, 2017 2:40 am
Forum: *Cycloalkanes
Topic: Naming (from example in course reader)
Replies: 1
Views: 443

### Re: Naming (from example in course reader)

Propyl has only 7 hydrogens while propane has 8 hydrogens. The carbon that is bonded to the parent chain is also bonded to two other carbons, so it can only be bonded to one hydrogen. The other two carbons in the cyclopropyl group have 3 hydrogens each, so in total there are three carbons and seven...
Fri Mar 17, 2017 2:34 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell potential
Replies: 1
Views: 257

### Re: Cell potential

I think it is because electric cell potential is essentially equal to the sum of the reduction potential and the oxidation potential. Because the anode is oxidized at the same rate that the cathode is reduced, the sum of the potentials does not change no matter the quantity.
Fri Mar 17, 2017 1:59 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: final exam 2013 q3c
Replies: 1
Views: 219

### Re: final exam 2013 q3c

The .05916 doesn't just come from plugging in 298K into the Nernst equation. You didn't make a mistake, but the difference is that the variation with .05916 has log with base 10 and the regular Nernst equation has natural log. That's why the numbers are different.
Fri Mar 17, 2017 12:22 am
Forum: *Organic Reaction Mechanisms in General
Topic: Hydrogen in Reaction Mechanisms
Replies: 1
Views: 471

### Re: Hydrogen in Reaction Mechanisms

Electrons will never go from hydrogen to something else, but electrons can go from something to hydrogen. A bond between hydrogen and another element can break however, and both electrons from the bond can go to the other element. But, these electrons come from the bond, not the hydrogen.
Thu Mar 16, 2017 11:31 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Constant Volume and Constant Pressure
Replies: 3
Views: 376

### Re: Constant Volume and Constant Pressure

Those equations are on the equation sheet, but you will probably have to know which one is for constant pressure or constant temperature. Also, a reversible heat transfer simply implies a change in volume under constant temperature; pressure can decrease or stay the same, but as you can see, the equ...
Thu Mar 16, 2017 11:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: heat question
Replies: 1
Views: 254

### Re: heat question

You would use this equation when calculating the heat energy necessary for phase changes (e.g. how much heat energy [q] would you need to completely convert 125g of water at 0 degrees Celsius into steam at 100 degrees celsius). If you remember the diagram for phase changes, the part of the diagram t...
Tue Mar 14, 2017 3:27 pm
Forum: Administrative Questions and Class Announcements
Topic: 1.23 in Introduction to Organic Chemistry Course reader
Replies: 1
Views: 289

### Re: 1.23 in Introduction to Organic Chemistry Course reader

There's no formula for how many structural isomers an alkane has, so you'd have to look them up. For alkanes with total # carbons 1-10, these are how many isomers the alkane has according to the internet. # carbons:# isomers

1:1, 2:1, 3:1, 4:2, 5:3, 6:5, 7:9, 8:18, 9:35, 10:75
Tue Mar 14, 2017 3:16 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 2008 Final question 3B
Replies: 1
Views: 226

### Re: 2008 Final question 3B

When the standard reduction potential of a half-cell reaction is negative, the electrode in that reaction is going to be oxidized. The rule of thumb is that the more negative the standard reduction potential, the more likely it is to be oxidized, and the more positive the potential, the more likely ...
Fri Mar 10, 2017 2:33 am
Forum: *Alkanes
Topic: "Iso"
Replies: 3
Views: 421

### "Iso"

In the quiz 1 preparation in the course reader, what makes the name of the substituent 4-isopropyl as opposed to just 4-propyl?
Sun Dec 04, 2016 3:19 am
Forum: Polyprotic Acids & Bases
Topic: Deprotonation Percentage
Replies: 1
Views: 581

### Re: Deprotonation Percentage

It was mention once or twice I think, there's an example of deprotonation in the course reader on page 156. It's labeled as ionization, but it's the same as deprotonation.
Sun Dec 04, 2016 3:09 am
Forum: Lewis Acids & Bases
Topic: 2013 Final #7B [ENDORSED]
Replies: 1
Views: 378

### 2013 Final #7B[ENDORSED]

Can somebody explain why CH3 has a weaker electron withdrawing ability than H?
Sat Dec 03, 2016 10:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Practice Final 2015 #5A
Replies: 1
Views: 351

### Practice Final 2015 #5A

Can someone explain how the formal charge for Corrin-DMB is calculated in the second part of the problem?
Sat Dec 03, 2016 8:50 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Example in Course Reader
Replies: 1
Views: 271

### Example in Course Reader

Can someone explain how the values for the change in molar concentration in the ICE table on p. 141 of the course reader is calculated?
Sat Dec 03, 2016 2:06 pm
Forum: Photoelectric Effect
Topic: Units in Photoelectric Effect
Replies: 1
Views: 279

### Units in Photoelectric Effect

What units do we need to convert to for energy when working with photoelectric effect problems?
Tue Nov 22, 2016 4:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Drawings for Final
Replies: 3
Views: 475

### Re: Drawings for Final

The only drawings we have done have been Lewis structures. There hasn't been any indication that we would have to draw a 3-D representation of a molecule, so I would definitely not be concerned with that. Just know how to draw Lewis structures and understand what the shape of the molecule is with th...
Fri Oct 28, 2016 8:36 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration exceptions
Replies: 1
Views: 1268

### Re: Electron Configuration exceptions

When zinc loses an electron, it'll lose it from its highest energy level at n=4. Zinc's ground state electron configuration is [Ar]3d10 4s2. Zinc with a positive charge of 2 (Zn^2+) would then have a configuration of [Ar] 3d10. Although it has the same number of electrons as nickel, their structures...
Fri Oct 21, 2016 7:13 pm
Forum: Lewis Structures
Topic: determining ionic/covalent from elctronegativity
Replies: 1
Views: 260

### Re: determining ionic/covalent from elctronegativity

I think the character of the bond has to be experimentally observed to find a definite answer to whether it's ionic or covalent. Between 1.5 and 2.0 is a gray area, so I doubt we would be expected to know what type of bonds a certain molecule/salt has.
Fri Oct 07, 2016 12:26 pm
Forum: Photoelectric Effect
Topic: frequencies [ENDORSED]
Replies: 1
Views: 276

### Re: frequencies[ENDORSED]

A TA recommended we know the wavelengths of visible light but other than that it seems we aren't expected to know the different parts of the spectrum
Wed Sep 28, 2016 11:22 pm
Forum: Properties of Light
Topic: Kinetic Energy
Replies: 4
Views: 736

### Re: Kinetic Energy

Does the equation only hold true under the assumption that the electrons carry no rotational kinetic energy? Why is only translational kinetic energy included in the equation?

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