Search found 20 matches

by Daniella Ching 4C
Tue Mar 08, 2016 5:21 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Torsional strain
Replies: 4
Views: 678

Re: Torsional strain

The torsional strain would not be negative, but it would decrease in value as you move to a more stable conformation. I'm not entirely sure though but that's what I think.
by Daniella Ching 4C
Wed Mar 02, 2016 5:22 pm
Forum: *Alkanes
Topic: Common Names
Replies: 4
Views: 547

Re: Common Names

I don't have a picture of the slides exactly, but here's the notes I jotted down from the slides! Hopefully it helps. In terms of the naming of the structures, you just count the carbons (everything under the iso section would be iso-[carbon chain] for example)
by Daniella Ching 4C
Thu Feb 25, 2016 11:08 pm
Forum: *Electrophiles
Topic: Reaction steps
Replies: 2
Views: 430

Re: Reaction steps

So how do we know if the steps occur at the same time or not? Would we need to know this or draw out the steps correctly for the quiz or final?
by Daniella Ching 4C
Mon Feb 15, 2016 10:50 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Solving for K (Rate Constant)
Replies: 2
Views: 453

Re: Solving for K (Rate Constant)

Shouldn't it give you the same rate constant k value for all the trials?
by Daniella Ching 4C
Mon Feb 15, 2016 10:45 pm
Forum: First Order Reactions
Topic: Half-life
Replies: 2
Views: 444

Re: Half-life

An explanation for why you want to need 0.693 or ln2 in the equation is this: For first order, the equation is ln [A] = -kt + ln[A] 0 For half-life, you want to find the concentration of A when it decreases by half, so [A]= \frac{1}{2} [A] 0 Plugging this into the equation, ln \frac{1}{2} [A] 0 = -k...
by Daniella Ching 4C
Tue Feb 02, 2016 11:29 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox in Acids and Bases
Replies: 1
Views: 417

Re: Balancing Redox in Acids and Bases

Since they give you the entire reaction, Cd(s) + 2 Ni(OH) 3 (s) -> Cd(OH) 2 (s) + 2 Ni(OH) 2 (s) you can balance the half reactions by first separating Cd and Ni into separate reactions. The first one would be: Cd(s) -> Cd(OH) 2 (s) and Ni would be: 2 Ni(OH) 3 (s) -> 2 Ni(OH) 2 (s) Then you can add...
by Daniella Ching 4C
Tue Jan 26, 2016 10:16 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Drawing Heating Curves
Replies: 2
Views: 419

Re: Drawing Heating Curves

I think that if they ask for a sketch of the graph, we won't need to label the melting point and boiling point on the graph. They are usually just checking the slopes relative to each other, and how long your lines for enthalpy of fusion and vaporization are relative to each other.
by Daniella Ching 4C
Wed Jan 20, 2016 11:10 pm
Forum: Phase Changes & Related Calculations
Topic: Heat of Fusion Title
Replies: 2
Views: 457

Re: Heat of Fusion Title

The definition of solid becoming liquid as fusion confused me too, since I thought of it the same way, as two objects becoming one. But often, fusion requires heat. I found this other definition online: "The noun fusion comes from the Latin word fundere, meaning melt, so fusion is the act of me...
by Daniella Ching 4C
Fri Jan 15, 2016 3:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Negative Entropy
Replies: 1
Views: 383

Re: Negative Entropy

It is not possible to have negative entropy, but there can be negative change in entropy. Positive change in entropy occurs more often and is more spontaneous because objects tend to go to a state of more disorder. However, if there are outside forces or changes made to the system, negative change i...
by Daniella Ching 4C
Thu Jan 07, 2016 5:55 pm
Forum: Phase Changes & Related Calculations
Topic: Steam
Replies: 2
Views: 392

Re: Steam

Will we need to solve problems where we have to find the change in heat and then use that and the specific heat capacities to calculate the final temperature of the water or of skin?
by Daniella Ching 4C
Mon Nov 30, 2015 10:05 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Question about Buffers and Use of a Salt
Replies: 4
Views: 627

Re: Question about Buffers and Use of a Salt

Since the conjugate of a strong base is a weak acid, does this mean that the salt (when dissolved) is a strong base? Would there be less salt then in a buffer solution than weak acid?
by Daniella Ching 4C
Sun Nov 29, 2015 10:29 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Second Deprotonations of Diprotic Acids
Replies: 4
Views: 3437

Re: Second Deprotonations of Diprotic Acids

Is Ka2 typically greater than Ka1 for most polyprotic acids? Is there a trend? Or would we have to calculate the Ka1 and Ka2 for each polyprotic acid in order to tell?
by Daniella Ching 4C
Mon Nov 23, 2015 9:08 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ignoring the change in equilibrium
Replies: 3
Views: 522

Re: Ignoring the change in equilibrium

The safest way (or a double check) to know whether to approximate or not is to see if the change is less than 5% of the original amount present. You can solve the problem by approximation first, then do a quick calculation to make sure that the change falls within 5%.
by Daniella Ching 4C
Sun Nov 15, 2015 10:00 pm
Forum: Naming
Topic: Iron vs ferrate & oh2
Replies: 3
Views: 595

Re: Iron vs ferrate & oh2

So if we were given the name for a coordination compound that has aqua in it, would we be expected to know whether to write (OH2) or (H2O)? For example, for triammineaquaplatinum(IV) chloride, can we just write out the chemical formula as: [Pt(NH3)H2O]Cl4
by Daniella Ching 4C
Tue Nov 03, 2015 10:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Helpful Video on Molecular Orbital Diagram
Replies: 2
Views: 439

Re: Helpful Video on Molecular Orbital Diagram

That's pretty much the way I understand the difference in the MO diagrams. For Z<8, the s and p levels are very close together because there is less of an energy difference between the two levels. Because of this, there is a greater repulsion between the electrons in the sigma s and sigma pz bonds, ...
by Daniella Ching 4C
Mon Oct 26, 2015 11:55 pm
Forum: Hybridization
Topic: Hybrid Orbitals
Replies: 1
Views: 313

Re: Hybrid Orbitals

I believe so! This also occurs in his example of benzene with its sp2 hybridization. The fourth electron would then probably create a pi bond in the double and triple bonds. Another way to check is to count how many regions of electron density are in the VSEPR structure, and determine its hybridizat...
by Daniella Ching 4C
Fri Oct 23, 2015 4:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar Angles
Replies: 4
Views: 1178

Re: Square Planar Angles

I don't think we need to know the VSEPR shape of a square pyramidal for this class.
by Daniella Ching 4C
Mon Oct 12, 2015 11:59 pm
Forum: Properties of Electrons
Topic: Quiz 1 Preparation Fall 2014 Question 10
Replies: 4
Views: 573

Re: Quiz 1 Preparation Fall 2014 Question 10

I used the equation from class (E=-hR/n^2) and got the right answer using that, so either version should work. However, I did the second part slightly differently than the work shown on page 26 of the workbook. I calculated out the energy for n=4 first, using (E=-hR/n^2), then plugged in the \Delta ...
by Daniella Ching 4C
Thu Oct 08, 2015 6:35 pm
Forum: Properties of Light
Topic: Frequency and Speed?
Replies: 2
Views: 465

Re: Frequency and Speed?

c= frequency x wavelength.
The frequency and wavelength are inverses of each other, while the speed stays constant.
by Daniella Ching 4C
Tue Sep 29, 2015 6:45 pm
Forum: Properties of Light
Topic: Rydberg Formula
Replies: 7
Views: 1958

Re: Rydberg Formula

When do you need to use the Rydberg Formula?

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