Search found 27 matches

by Christine Burke 1G
Sun Dec 06, 2015 12:52 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: 2014 Final #8- Raising pH
Replies: 2
Views: 448

Re: 2014 Final #8- Raising pH

I thought it was being added to the base because in the Henderson Hasselbach equation, it's the log of base over acid.
by Christine Burke 1G
Wed Dec 02, 2015 4:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape from AXE model
Replies: 2
Views: 510

Re: Shape from AXE model

I was under the impression AX2E is bent.
by Christine Burke 1G
Tue Dec 01, 2015 10:33 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH of Weak Acids and Bases
Replies: 1
Views: 298

Re: pH of Weak Acids and Bases

It does depend on how small the value of K is. If I remember correctly, 10^-4 is the cut off.
by Christine Burke 1G
Wed Nov 25, 2015 7:27 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Homework Question 12.51 A
Replies: 5
Views: 716

Re: Homework Question 12.51 A

After doing more of the homework, I think I figured it out. Bond strength is important in binary acids (acids with like HCl and HF). Whereas electronegativity is important in non binary acids.
by Christine Burke 1G
Wed Nov 25, 2015 7:21 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: conjugate acids and bases
Replies: 2
Views: 378

Re: conjugate acids and bases

I'm not positive, but I think because Ka*Kb=Kw, the larger the one value is the smaller the other has to be because Kw is a constant.
by Christine Burke 1G
Sun Nov 22, 2015 4:50 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: ICE Box for weak Acids and Bases
Replies: 1
Views: 594

Re: ICE Box for weak Acids and Bases

Going off of what was said in lecture, it is my understanding that we don't need an ICE box for strong acids and bases because you can assume they were 100% disassociated.
by Christine Burke 1G
Sun Nov 22, 2015 12:45 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Homework Question 12.51 A
Replies: 5
Views: 716

Re: Homework Question 12.51 A

I'm not positive but I think that HCl has a weaker bond strength than HF because Chlorine is larger than Fluorine. Bond strength decreases as you go down a group. A larger radius means a longer bond, longer bonds mean weaker bonds. Weaker bonds are easier to break, resulting in the compound being mo...
by Christine Burke 1G
Sat Nov 14, 2015 8:41 pm
Forum: Naming
Topic: Order when writing compounds
Replies: 2
Views: 299

Re: Order when writing compounds

Thanks for the response! I just read something form the chem moderator I would add in case anyone else looks at this thread. Anionic ligands come before neutral ligands when writing the formula.
by Christine Burke 1G
Sat Nov 14, 2015 8:38 pm
Forum: Naming
Topic: complex ion
Replies: 2
Views: 386

Re: complex ion

Also, this ion is negatively charged. Remember that when an ion has a negative charge we add -ate to the end. Cobalt becomes cobaltate. If it has a Latin equivalent, we switch to that. If you notice you never see ironate we only see ferrate.
by Christine Burke 1G
Sat Nov 14, 2015 8:36 pm
Forum: Naming
Topic: complex ion
Replies: 2
Views: 386

Re: complex ion

I'm not positive, but cuprate is the latin version of copper like ferrate is for iron. So I think the answer is just allowing leniency for people who didn't know the latin word for copper is cuprate. If you look at the two correct answers, the only difference is copper and cuprate.
by Christine Burke 1G
Sat Nov 14, 2015 8:34 pm
Forum: Naming
Topic: Alphabetical Order in Naming?
Replies: 1
Views: 337

Re: Alphabetical Order in Naming?

We ignore the greek prefixes when looking at alphabetical order. So diammine would come before chloro.
by Christine Burke 1G
Sat Nov 14, 2015 8:32 pm
Forum: Naming
Topic: Formula Charge
Replies: 4
Views: 404

Re: Formula Charge

I think I figured it out. When something has an overall charge that is negative the metal name gets an ate. If this had a negative charge it would end with cobaltate(III). (By the way, if it has a latin name and the compound is negative we switch to that so you would not have ironate but ferrate.) I...
by Christine Burke 1G
Sat Nov 14, 2015 8:25 pm
Forum: Naming
Topic: Formula Charge
Replies: 4
Views: 404

Re: Formula Charge

I'm not positive about the naming, but a sulfate ion (SO4) has a 2 minus charge not a three minus charge.
by Christine Burke 1G
Sat Nov 14, 2015 5:17 pm
Forum: Naming
Topic: Aqua or Hydrate
Replies: 2
Views: 375

Re: Aqua or Hydrate

In this case it is aqua. Most of the time, at least from the homework and the examples we've seen in this course, it's aqua.If something is a hydrate it will be written like (Compound here) dot H20. There is an actual dot written between them, it looks like multiplication.
by Christine Burke 1G
Sat Nov 14, 2015 2:26 pm
Forum: Naming
Topic: When to use OH2 and H2O?
Replies: 1
Views: 249

When to use OH2 and H2O?

If we write (OH2) while the solutions manual has (H20), would it be considered wrong? Does it make a big difference writing OH2 instead of H2O? If it does make a big difference how do we figure out which one to use? Thank you.
by Christine Burke 1G
Sat Nov 14, 2015 2:24 pm
Forum: Naming
Topic: Order when writing compounds
Replies: 2
Views: 299

Order when writing compounds

When they give us the name and we have to write the complex's formula, does it matter if we put like (CN)6(H20)2 versus (H20)2(CN)6? (This is just a random example I picked.) If order does matter, how do we figure out which one goes first? I know that when we go to the name from the formula it's alp...
by Christine Burke 1G
Sat Nov 14, 2015 2:22 pm
Forum: Naming
Topic: Figuring out if something is polydentate
Replies: 1
Views: 182

Figuring out if something is polydentate

Are we supposed to be able to figure out if a compound is ploydentate? If so, do we draw out the whole molecule and figure it out from there? If we don't have to know how to do that, do we just memorize some of the ones that are polydentate? Which ones should we have memorized?
by Christine Burke 1G
Sat Nov 14, 2015 12:20 pm
Forum: Naming
Topic: Naming [Co(CN)5(OH2)]2-?
Replies: 2
Views: 325

Naming [Co(CN)5(OH2)]2-?

This is numer 29 c for chapter 17. I wrote the name as aquapentacyanidocoboltate(III) ion but the solutions manual has aquapentacyanocoboltate(III) ion. Does it matter if it's cyanido or cyano? If it does, when do you use which? Thank you!
by Christine Burke 1G
Tue Nov 03, 2015 5:37 pm
Forum: Ionic & Covalent Bonds
Topic: Why is LiH more ionic than HCl?
Replies: 2
Views: 720

Re: Why is LiH more ionic than HCl?

Thanks! That does help. I forgot that Hydrogen is not a metal even though it's placed in with the metals. So it makes sense that bonding between a metal and nonmetal would be more ionic than bonding between two nonmetals.
by Christine Burke 1G
Tue Nov 03, 2015 1:26 pm
Forum: Ionic & Covalent Bonds
Topic: Why is LiH more ionic than HCl?
Replies: 2
Views: 720

Why is LiH more ionic than HCl?

This is question 6B from the Fall 2011 midterm. It asks whether LiH or HCl is more ionic, the answer given is LiH. Because of differences in electronegativity, I thought HCl would be more ionic because Hydrogen and Chlorine are farther away from each other than Lithium and Hydrogen. So why is LiH th...
by Christine Burke 1G
Tue Nov 03, 2015 1:13 pm
Forum: Trends in The Periodic Table
Topic: Arranging S2-, Cl-, and P3- in order or ionic radius
Replies: 1
Views: 30694

Arranging S2-, Cl-, and P3- in order or ionic radius

This is question 5B on the practice midterm for fall 2014. The question says, "Arrange S2+, Cl-, and P3- in order of increasing ionic radius. The answer is Cl-, S2-, and P3-. Why is this the order? How do charges affect ionic radius?
by Christine Burke 1G
Thu Oct 22, 2015 4:35 pm
Forum: Lewis Structures
Topic: Lewis Structures (Conceptual)
Replies: 2
Views: 280

Re: Lewis Structures (Conceptual)

Lewis structures are a model to help us think about bonding. It tells us how many regions of electron densities there are and which atoms are bonded to which, with single, double, or triple bonds, and shows us lone pairs. However, they do not accurately depict what atoms bonded together really look ...
by Christine Burke 1G
Wed Oct 21, 2015 4:13 pm
Forum: Dipole Moments
Topic: How do you predict polarity for molecules?
Replies: 1
Views: 635

How do you predict polarity for molecules?

For number 27 in chapter 4, we have to predict whether C5H5N will be polar or not. It tells us this molecule is like benzene. Should we have the structure of benzene memorized? Because if not how does that help us? And then as far as predicting polarity between atoms, doesn't it depend on electroneg...
by Christine Burke 1G
Mon Oct 12, 2015 12:27 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Why are Copper and Chromium exceptions?
Replies: 3
Views: 23675

Why are Copper and Chromium exceptions?

I understand Cu and Cr are exceptions when writing electron configurations, but on a quantum level, why are they exceptions?
by Christine Burke 1G
Sat Oct 03, 2015 4:51 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Course reader- Which is the uncertainty for the electron?
Replies: 3
Views: 517

Re: Course reader- Which is the uncertainty for the electron

Thank you for the answers. I think I understand what Sparks 55 3f is saying that since we do not have a definite position, we are solving for an indefinite velocity. This especially makes sense because in the course reader, the answer says \Delta v equals 2.3X10^5 meters per second. This makes a lot...
by Christine Burke 1G
Sat Oct 03, 2015 2:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Course reader- Which is the uncertainty for the electron?
Replies: 3
Views: 517

Course reader- Which is the uncertainty for the electron?

In the course reader on page 53, in the question it says, "The electron is not confined to the nucleus and we now know, from experimental observation, that the size of an atom is determined by its electron outside of the nucleus. For H-atom the electron is confined to its atomic diameter of 2.5...

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