Search found 127 matches

by Niharika Reddy 1D
Tue Dec 02, 2014 11:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determining number of ligands
Replies: 7
Views: 2294

Re: Determining number of ligands

The question states that Pt2+ is forming a square planar complex, so that information was given to us.
by Niharika Reddy 1D
Mon Dec 01, 2014 8:58 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordinate Compounds #16.35
Replies: 1
Views: 332

Re: Coordinate Compounds #16.35

The coordination number is the number of bonds the central ion makes. Table 16.4 was probably given as a reference to see what the formulas for en and edta (in c and d) are to determine how many bonds each ligand can make. a) is straightforward, with 4 chlorine anions bonded to the central nickel io...
by Niharika Reddy 1D
Mon Dec 01, 2014 6:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: From K to Kc
Replies: 1
Views: 415

Re: From K to Kc

No; only gaseous products and reactants are taken into account.

delta n = (Total moles of gas on the products side) - (Total moles of gas on the reactants side).
by Niharika Reddy 1D
Mon Dec 01, 2014 5:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Square Planar complexes
Replies: 1
Views: 399

Re: Square Planar complexes

All square planar complexes have 4 bonds to the central metal ion, not necessarily 4 ligands. This means the central metal ion forms 4 bonds, and the same ligand can provide multiple bonds to the central metal ion, given it has multiple bond sites. Since en is a bidentate, each en ligand has 2 bond ...
by Niharika Reddy 1D
Sun Nov 30, 2014 10:02 am
Forum: Ideal Gases
Topic: Relationship between Kc and K
Replies: 1
Views: 521

Re: Relationship between Kc and K

"c" is concentration, which is moles/liter, or n/V. If you rearrange the ideal gas law to get P=(n/V)RT, it can be rewritten as P=cRT, and cRT/P is used in that equation.

Hope this clears things up!
by Niharika Reddy 1D
Sat Nov 29, 2014 11:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW 10.39
Replies: 3
Views: 3878

Re: HW 10.39

It was probably just left out when typing the explanation but when you calculate Kc, I believe it should be:
[x][x]/[.0086-2x]^2
not:
[x][x]/[.0086-x]^2
as the student above has stated.
by Niharika Reddy 1D
Sat Nov 29, 2014 9:35 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Cubic Equations
Replies: 8
Views: 1468

Re: Cubic Equations

In lecture, Professor Lavelle said it is safe to approximate and assume the change (x) is negligible when K is 10 -5 or smaller. More specifically, we can approximate when the change in composition (x) is less than 5% of the initial concentration, and this will be the case when K is less than or equ...
by Niharika Reddy 1D
Wed Nov 19, 2014 9:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Conversions regarding pressures
Replies: 2
Views: 460

Re: Conversions regarding pressures

For units, I don't think it matters as long as you're consistent (i.e., make sure the gas constant includes the same units as what you use for pressure). Regarding you second question, you can use the ideal gas law (PV=nRT) to convert between partial pressure and molar concentration. P=(n/V)(RT) is ...
by Niharika Reddy 1D
Wed Nov 19, 2014 9:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Chart
Replies: 2
Views: 460

Re: ICE Chart

The direction of the reaction indicates whether the concentrations of products/reactants decrease or increase. For this problem, since there is no product to begin with (the initial molar concentration of N2O is 0), we know the reactants are going to form products and the forward reaction will occur...
by Niharika Reddy 1D
Mon Nov 17, 2014 3:08 pm
Forum: Naming
Topic: 16.29 part c
Replies: 1
Views: 305

Re: 16.29 part c

I think you copied down the problem incorrectly. It's supposed to be tetraamminediaquacobalt(III) bromide. There are 2 H2Os because there is a prefix "di" before aqua in the name, and di indicates that there are 2. We know the subscript for Br is 3 because the whole compound is neutral and...
by Niharika Reddy 1D
Mon Nov 17, 2014 2:54 pm
Forum: Naming
Topic: thiocyanato(kN)pentaaqua(III) iron
Replies: 1
Views: 511

Re: thiocyanato(kN)pentaaqua(III) iron

I asked our TA about that one last week and he said pentaaqua should come first because, as you said, we ignore the prefixes when listing ligands in alphabetical order.
As for the "thio" in thiocyanato, I'm not sure if this is what you're asking but it comes from the S in SCN-.
by Niharika Reddy 1D
Sun Nov 09, 2014 8:22 am
Forum: Hybridization
Topic: S Character of Hybrids
Replies: 2
Views: 616

Re: S Character of Hybrids

You can think of s character as the percent composition of s. •sp3 is 1/4 (25%) s in character since there is 1 s and 3/4 (75%) p in character The bond angle corresponding to sp3 is 109.5° •sp2 is 1/3 (~33.3%) s in character and 2/3 (~66.6%) p in character The bond angle corresponding to sp2 is 120°...
by Niharika Reddy 1D
Sat Nov 08, 2014 6:43 pm
Forum: Hybridization
Topic: Benzyne hybridization
Replies: 2
Views: 4231

Re: Benzyne hybridization

The student above is referring to benzene (C6H6), not benzyne (C6H4). I have drawn and attached an image of the benzyne molecule below with the hybridization of each carbon atom written next to it. To determine hybridization, find the regions of electron density around the carbon atom. The 2 carbon ...
by Niharika Reddy 1D
Sat Nov 08, 2014 4:23 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Molecular Orbital Diagram
Replies: 4
Views: 812

Re: Molecular Orbital Diagram

When there is a heteronuclear diatomic molecule, use the molecular orbital diagram for the atom with the lower nuclear charge.

In CF, C has the lower nuclear charge so use the MO diagram for Z<8.

Hope this helps!
by Niharika Reddy 1D
Sat Nov 08, 2014 9:15 am
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 1
Views: 1780

Re: Dipole Moments

SO3 2- has a trigonal pyramidal molecular geometry, with one lone pair and 3 oxygen atoms around the sulfur atom. Since oxygen is more electronegative than sulfur, all three bonds' dipole moments would point from the partial positive sulfur towards the partial negative oxygen. Because the lone pair ...
by Niharika Reddy 1D
Thu Nov 06, 2014 5:21 pm
Forum: Lewis Structures
Topic: Structures of Polyatomic Species
Replies: 1
Views: 392

Re: Structures of Polyatomic Species

Cations have a positive charge and anions have a negative charge. The ammonium ion has a plus 1 positive charge (NH4+) and the sulfate ion has a minus 2 negative charge (SO4 2-), which is why ammonium ions are cations and sulfate ions are anions. We need two ammonium ions to bond with a sulfate ion ...
by Niharika Reddy 1D
Thu Nov 06, 2014 4:53 pm
Forum: Dipole Moments
Topic: Ch.3 #19
Replies: 1
Views: 418

Re: Ch.3 #19

The lone pair does not affect the partial charges of each dipole moment; it only affects the net dipole of the entire molecule. Fluorine will always be more electronegative than sulfur, so all 4 bonds' dipole moments will point to the fluorine atoms from the sulfur atoms. The molecule is polar is be...
by Niharika Reddy 1D
Sat Nov 01, 2014 1:23 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: 2.81 Polarizability
Replies: 2
Views: 1942

Re: 2.81 Polarizability

The student above mixed up his terms. Having high polarizing power is different from being highly polarizable. Polarizing power is the ability to cause electron cloud distortion while being highly polarizable is readily undergoing a large distortion. Small, highly charged cations have high polarizin...
by Niharika Reddy 1D
Thu Oct 30, 2014 3:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bonds and Energy
Replies: 1
Views: 309

Re: Bonds and Energy

Lewis structures that do not correspond to the same energy do not in general make the same contribution to a resonance structure. One way to decide which structures are likely to make the major contribution is to compare the number of valence electrons distributed around each atom in a structure wit...
by Niharika Reddy 1D
Tue Oct 28, 2014 3:01 pm
Forum: Lewis Structures
Topic: Lewis Structure for COCl2
Replies: 2
Views: 5737

Re: Lewis Structure for COCl2

Since the double bond can be placed in more than one place without rearranging the atoms, COCl2 exhibits resonance. Its Lewis structure can be drawn 3 ways: the first with a double bond between carbon and oxygen, the second with a double bond between carbon and one chlorine, and the third with a dou...
by Niharika Reddy 1D
Wed Oct 22, 2014 8:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence Electrons
Replies: 3
Views: 7251

Re: Valence Electrons

Valence electrons are considered to be all of those written after the preceding noble gas configuration, so scandium actually has 3 valence electrons. I was confused about this as well since I initially thought only the electrons in the outermost shell are valence electrons, but elements can have up...
by Niharika Reddy 1D
Sun Oct 19, 2014 1:11 pm
Forum: Limiting Reactant Calculations
Topic: Combustion Analysis
Replies: 3
Views: 647

Re: Combustion Analysis

Combustion is the burning of a compound in the presence of oxygen, so O2 is always a reactant in combustion even if it isn't stated explicitly.

Hope this helps!
by Niharika Reddy 1D
Fri Oct 17, 2014 9:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Valence Electrons
Replies: 3
Views: 10743

Re: Valence Electrons

Edit: Cobalt has 9 valence electrons. The 3d subshell has a higher energy than the 4s one, and since electrons fill up in an order of increasing energy, the 3d subshell is filled after 4s. However, once the 4s orbital is filled and electrons enter the 3d orbitals, the 3d orbitals are lower in energy...
by Niharika Reddy 1D
Mon Oct 13, 2014 11:24 pm
Forum: DeBroglie Equation
Topic: de Broglie wavelength vs. Planck length
Replies: 3
Views: 897

Re: de Broglie wavelength vs. Planck length

The size of the wavelength determines whether or not something has measurable wavelike properties. I use the wavelengths in the electromagnetic spectrum as a guide. Since gamma rays (wavelength of about .1 pm, or 10^-13 m) can be detected, moving objects with wavelengths that are about this short, m...
by Niharika Reddy 1D
Sat Oct 11, 2014 9:04 am
Forum: Photoelectric Effect
Topic: Ek = 1/2mv^2....how do we get the "m"?
Replies: 6
Views: 5170

Re: Ek = 1/2mv^2....how do we get the "m"?

I just did the calculation in the problem again to verify and it checks out. (1/2)(9.109x10^-31 kg)(6.68x10^5 m/s)^2 =2.03x10^-19 J If you were to multiply just the 10^-31 and (10^5)^2, you would get 10^-21. After you calculate (1/2)(9.109)(6.68^2), you get 203, so the answer is 203x10^-21 at this p...
by Niharika Reddy 1D
Thu Oct 09, 2014 10:30 pm
Forum: Photoelectric Effect
Topic: Ek = 1/2mv^2....how do we get the "m"?
Replies: 6
Views: 5170

Re: Ek = 1/2mv^2....how do we get the "m"?

So the mass of an electron is the same regardless of what element it is? 9.109 x 10^-31 kg is something that will be given or do we have to memorize it? Im asking because the assessment of the photoelectric effect module had a problem that required the mass of a sodium electron for the same equatio...
by Niharika Reddy 1D
Wed Oct 08, 2014 8:48 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro's Number
Replies: 2
Views: 856

Re: Avogadro's Number

Avogadro's number is the number of objects (i.e. atoms, ions, molecules, formula units, or anything really, as you mentioned humans) per mole. A mole is like a "dozen"--just a term that represents how many objects it contains. 12 is to a dozen what Avogadro's number (6.022x10^23) is to a m...

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