Search found 29 matches

by Vanessa A 3F
Sat Dec 05, 2015 5:40 pm
Forum: Naming
Topic: using bis, tris, tetrakis
Replies: 4
Views: 5610

Re: using bis, tris, tetrakis

The complex ligands that are in our course reader are oxalato, (en), and (dien). These and other complex ones are the only ligands you would need to use bis, tris, and tetrakis for. For all other ligands, use the usual prefixes of bi, tri, tetra.
by Vanessa A 3F
Sat Dec 05, 2015 5:36 pm
Forum: *Making Buffers & Calculating Buffer pH (Henderson-Hasselbalch Equation)
Topic: Henderson-Hasselbalch equation
Replies: 4
Views: 1346

Re: Henderson-Hasselbalch equation

In this class we will mostly get questions where we can't use the HH equation. Unless the question has the word "buffer" in it, then you can go ahead and use it. Otherwise it's hard to tell
by Vanessa A 3F
Sun Nov 29, 2015 9:06 pm
Forum: Naming
Topic: Adding "-ate" to a metal
Replies: 5
Views: 851

Re: Adding "-ate" to a metal

It's always going to be adding -ate. I think you're thinking of ions like nitrite and sulfite
by Vanessa A 3F
Sun Nov 29, 2015 9:02 pm
Forum: Naming
Topic: Naming this compound
Replies: 2
Views: 961

Re: Naming this compound

The correct answer is pentaamminechlorocobalt (III) chloride *Note that there is no di prefix in front of the chloride. To find the oxidation number: There are some atoms and polyatomic ions in coordination compounds that have a charge. These should be memorized, so that you know what proper oxidati...
by Vanessa A 3F
Sun Nov 29, 2015 8:55 pm
Forum: Naming
Topic: naming ligands
Replies: 2
Views: 526

Re: naming ligands

[Co (NH3)5 Cl] Cl 2H2O

Remember to always check the charges of the components when writing the formula in case there needs to be more than one atom of something
by Vanessa A 3F
Sun Nov 29, 2015 8:52 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Gas # of Moles, Increase the pressure
Replies: 3
Views: 693

Re: Gas # of Moles, Increase the pressure

So if the pressure decreases, the reaction shifts towards the less moles of gas side? How about when the volume decreases? What side does it proceed to and how does it affect concentration
by Vanessa A 3F
Sun Nov 29, 2015 8:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octet Rule
Replies: 3
Views: 547

Re: Octet Rule

In our class I think we won't deal with the extremely complicated cases and instead mainly focus on the atoms in the second period of the periodic table instead, and as long as the formal charge agrees with the Lewis structure you come with, that's fine. For example, SF 6 and PF 5 should intuitively...
by Vanessa A 3F
Sun Nov 29, 2015 8:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond lengths
Replies: 3
Views: 638

Re: Bond lengths

there are two things to keep in mind 1. Triple bonds are the shortest, and single bonds are the longest. We determine how many bonds there are from the Lewis structure that we determine to be the best. 2. A molecular orbital theory chart may tell you that the bond between two atoms is 1.5, or 2.5, w...
by Vanessa A 3F
Sun Nov 22, 2015 7:46 pm
Forum: Naming
Topic: Adding "-ate" to a metal
Replies: 5
Views: 851

Re: Adding "-ate" to a metal

If the metal is a part of a negatively charged anion, add "ate" to the name. Otherwise, just use the name of the metal, and remember to always include the metal's oxidation state.
by Vanessa A 3F
Sun Nov 22, 2015 7:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Concentrations
Replies: 2
Views: 356

Re: Equilibrium Concentrations

If the concentrations remain constant, so will the ratio.
If the rate of the forward reaction is equal to the reverse reaction, then the chemicals are in chemical equilibrium. K signifies a ratio that does not change.
by Vanessa A 3F
Sun Nov 15, 2015 5:04 pm
Forum: Bond Lengths & Energies
Topic: Bond Order Meaning
Replies: 3
Views: 6693

Re: Bond Order Meaning

A bond order of 1.5 signifies that the Lewis structure of the compound has resonance structures, and that the bonds of the compound will have the characteristics of both a single and double bond. The resonance structures don't truly tell us how the bonds are in reality, so a bond order of 1.5 helps ...
by Vanessa A 3F
Sun Nov 15, 2015 5:00 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Lewis structures
Replies: 11
Views: 1626

Re: Lewis structures

If the formal charges you're getting aren't 0, try to go back and either add bonds, or lone pairs (if applicable), to make the formal charge more favorable. Most of the time, using a double or triple bond instead of a single bond solves the problem.
by Vanessa A 3F
Sun Nov 15, 2015 4:52 pm
Forum: Naming
Topic: When to use "-ate" when naming compounds
Replies: 1
Views: 372

Re: When to use "-ate" when naming compounds

For [Co(NH3)6]3+, the name would be hexaamminecobalt(III), because this is a positively charged complex ion.
Only when the total charge is negative do you end a metal's name with "ate".
by Vanessa A 3F
Sat Nov 07, 2015 8:16 pm
Forum: Photoelectric Effect
Topic: Work Function vs De Broglie
Replies: 4
Views: 3333

Re: Work Function vs De Broglie

E=hv simply means Energy = Planck's consant x velocity Ephoton = work function + kinetic energy is the same thing as E incident = E threshold + E excess This is basically saying that in the photoelectric effect, the energy of the incident light that hits the metal (E photon), equals the minimum ener...
by Vanessa A 3F
Sat Nov 07, 2015 8:08 pm
Forum: Photoelectric Effect
Topic: when to use photoelectric effect or debroglie?
Replies: 3
Views: 1112

Re: when to use photoelectric effect or debroglie?

Using the De Brogile equation to find the wavelength of an electron is the only correct way to do so. There are some equations, like E=hc and c=lambda*velocity, that are only to be used when you're dealing with light. And there are some equations that are only to be used with massive objects, things...
by Vanessa A 3F
Sat Oct 31, 2015 3:36 pm
Forum: Hybridization
Topic: VSEPR Geometry
Replies: 2
Views: 1717

Re: VSEPR Geometry

There are 6 electron pair geometries to remember, and from them, you can derive the molecular geometry 2 electron dense regions? EPG is linear 3 electron dense regions? EPG is trigonal planar 4? EPG is tetrahedral 5? EPG is trigonal bipyramid 6? EPG is octahedral After you decide what a molecule's E...
by Vanessa A 3F
Sat Oct 31, 2015 3:27 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 2
Views: 440

Re: Covalent Bonds

"Covalent character" is usually thought of in relative terms, and refers to the relative covalent character of ionic bonds. This is because we already know all covalent bonds have covalent character, by definition. So, an ionic bond has more covalent character if there is less of a differe...
by Vanessa A 3F
Sat Oct 31, 2015 3:20 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond Order
Replies: 4
Views: 618

Re: Bond Order

The greater the bond order is, the greater the bond strength is.
A BO of 1 denotes a single bond
A BO of 2 denotes a double bond
A BO of 3 denotes a double bond

As the bond order increases, so does the strength of the bond.
by Vanessa A 3F
Thu Oct 22, 2015 9:06 pm
Forum: Student Social/Study Group
Topic: Top of the Hill Study Group
Replies: 5
Views: 1084

Re: Top of the Hill Study Group

I'm at summit too, totally down for a study group.
by Vanessa A 3F
Thu Oct 22, 2015 9:02 pm
Forum: Lewis Structures
Topic: Bonds
Replies: 2
Views: 521

Re: Bonds

When making a Lewis Structure, you don't initially know how many bonds there will end up being. So start by counting up all of the valence electrons each atom in the molecule has. This is how many electrons there need to be in the Lewis structure. Then use a single bond to connect them to each other...
by Vanessa A 3F
Wed Oct 14, 2015 9:44 pm
Forum: Empirical & Molecular Formulas
Topic: Using mass percent
Replies: 1
Views: 465

Re: Using mass percent

"why is it unnecessary to find the mass percent after converting the grams of CO2 and H2O into grams of C and H?" In a question like this, you do use mass percents, in the beginning when you are converting the grams of CO2 and H2O to grams of C and H. The steps to solve are -Find mass per...
by Vanessa A 3F
Wed Oct 14, 2015 9:35 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Finding Quantum Numbers
Replies: 2
Views: 569

Re: Finding Quantum Numbers

n= principle quantum number, the shell the electron is in. For example, if an atom's electron configuration ends with 5s1, its n=5. L=numbers from 0 to n-1. So for the example mentioned above, l can be 0, 1, 2, 3, or 4. M l = can be positive and negative possible l values. -4, -3, -2, -1, 0, 1, 2, 3...
by Vanessa A 3F
Sat Oct 10, 2015 2:51 pm
Forum: Significant Figures
Topic: Which number to use?
Replies: 6
Views: 880

Re: Which number to use?

Our reference sheet says c= 2.99792 x 10^8 m/s, so I'd use as many sig figs as possible, like 2.998 x 10^8 just to be safe and as precise as possible. Try a problem where you use 3.0 x 10^8 and do it again using c=2.998 x 10^8 m/s. As you'll find, the answers are slightly different, but if your fina...
by Vanessa A 3F
Sat Oct 10, 2015 2:40 pm
Forum: SI Units, Unit Conversions
Topic: Exercise 1 in Fundamentals Section
Replies: 2
Views: 708

Re: Exercise 1 in Fundamentals Section

You're right, the radius is just what's given in question E3, but you'll have to double it to find the diameter of an atom and solve the problem.
by Vanessa A 3F
Sat Oct 10, 2015 2:36 pm
Forum: SI Units, Unit Conversions
Topic: Preference of Units [ENDORSED]
Replies: 2
Views: 580

Re: Preference of Units [ENDORSED]

Yes, they mean the same thing. Use whichever you prefer.
by Vanessa A 3F
Sat Oct 10, 2015 2:31 pm
Forum: SI Units, Unit Conversions
Topic: What prefixes do I need to know? [ENDORSED]
Replies: 6
Views: 1065

Re: What prefixes do I need to know? [ENDORSED]

It would be useful to memorize the highlighted prefixes as they are the most common.
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by Vanessa A 3F
Sat Oct 10, 2015 2:20 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Penetration
Replies: 2
Views: 523

Re: Penetration

I hope this website helps with its explanation of orbital penetration. http://chemwiki.ucdavis.edu/?title=Physical_Chemistry/Quantum_Mechanics/10:_Multi-electron_Atoms/Multi-Electron_Atoms/Penetration_%26_Shielding#Orbital_Penetration"onclick="window.open(this.href);return false; I think the main id...
by Vanessa A 3F
Sat Oct 10, 2015 2:12 pm
Forum: Properties of Light
Topic: Homework problem 2.43
Replies: 1
Views: 464

Re: Homework problem 2.43

Hi Madeline. I can see how you got the answer you did by looking at the periodic table. However, notice that Tungsten's (W) atomic number is 74. Now, do you notice how in period 6, the atomic numbers skip from #57 (Lanthanum) to #72 (Hafnium)? That's because a series of f-block elements actually go ...
by Vanessa A 3F
Wed Sep 30, 2015 10:46 pm
Forum: Significant Figures
Topic: Common molar masses to remember
Replies: 3
Views: 671

Re: Common molar masses to remember

Very helpful, thank you!

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