CHEMISTRY COMMUNITY

Mariam Baghdasaryan 4F

If the coordination compound has the ligand ethylenediaminetetraacetato is this written simply as (edta) or (edta 4-) when naming the compound because technically they're two different things?

Mariam Baghdasaryan 4F

Why is H20 not a bidentate even though it has 2 lone pairs?

Mariam Baghdasaryan 4F

Do have to memorize all of these ligands?

Mariam Baghdasaryan 4F

The two carbons that don't have an H attached to them have an sp hybridization, so they would want to have the linear arrangement. But because the atoms are arranged to form a ring, the two carbons have a strained structure (meaning they won't form 180 degree angles). This is why it is reactive.

Mariam Baghdasaryan 4F

I don't think so, but I would check with your T.A.

Mariam Baghdasaryan 4F

Does a tetrahedral like CH4 have 5 109.5 degree bond angles?

Mariam Baghdasaryan 4F

It is true that the H-Br bond length is shorter than the H-I bond length. However, what you need to consider is also the size of the atoms. I is a larger atom than Br, so it has more electrons that increase the strength of the dispersion forces and the attractive interactions. Due to the greater att...

Mariam Baghdasaryan 4F

Trigonal Bipyramidal: AX5
Seesaw: AX4E
Square Pyramidal: AX5E

A represents the central atom
X bonded atom
E lone pair

Notice how they are not exactly the same because of the lone pairs.

Mariam Baghdasaryan 4F

There are two 90 degree lone-pair-bonding-pair repulsions, but I am not sure about the number of 120 degree bond angles.

Mariam Baghdasaryan 4F

Professor Lavelle drew the p-p orbitals on the board which helped me visualize this. Note that a p-orbital has 2 lobes. For the "end-to-end," if p-orbital 1 and p-orbital 2 are in the horizontal direction next to each other, the "end" of the right lobe of p-orbital 1 will "o...

Mariam Baghdasaryan 4F

I believe that Professor Lavelle said we don't need to know the exact bond angles for specific molecules, but we should know it for the general shape. So if you identify a molecule to have the trigonal pyramidal shape (3 bonding pairs and 1 lone pair), you can say that the bond angles for that molec...

Mariam Baghdasaryan 4F

Why is lone-lone pair repulsion stronger than lone-bonding pair and bonding-bonding pair?

Mariam Baghdasaryan 4F

In our lecture notes, the energy is negative i.e. for ion-ion it is -250 kJ/mol, but in the book all the values are positive. Why is this?

Mariam Baghdasaryan 4F

Something like NaCl is known to be a salt with an ionic bond between Na+ and Cl-. You have to keep in mind though that all ionic bonds have covalent character, meaning electrons are going to be "shared" between the Na+ and Cl-. The Na+ which is the cation has polarizing power and can exert...

Mariam Baghdasaryan 4F

I don't think it can because if it has more than 4 single bonds, then that means the central atom has more than 8 valence electrons, already suggesting an expanded octet. The resonance structures also have to reflect this. If an atom does not have a d-orbital or f-orbital for more electrons, it can'...

Mariam Baghdasaryan 4F

Which HW problems can we turn in this week? 3.73 and onward, or are all chapter 3 problems acceptable?

Mariam Baghdasaryan 4F

Thank you that makes sense!

Mariam Baghdasaryan 4F

The more stable structure of SO42- has 2 double bonds and 2 single bonds with O, but the single bonds have a formal charge of -1. Why can't those single bonds also become double bonds so that the formal charge becomes 0. Since S can accommodate more than 8 valence electrons, wouldn't this work?

Mariam Baghdasaryan 4F

So In is [Kr] 4d10 5s2 5p1. So for In3+, I looked at the periodic table and moved 3 to the left, arriving at Palladium. Hence, I thought the electron configuration of palladium/In 3+ will be [Kr] 4d8 5s2, but palladium is an exception like chromium and copper so its electron configuration is [Kr] 4d...

Mariam Baghdasaryan 4F

Do we need to know the # of valence electrons for the 3d elements?

Mariam Baghdasaryan 4F

For example, the electron configuration for Selenium (Se) is [Ar] 3d10 4s2 4p4.

If I am looking at n=4, then l can be the 0 (s) ,1 (p), 2 (d) and 3 (f) subshells. Since Selenium goes up to 4p4, does that mean it has empty l=2 and l=3 subshells, or does it not have those subshells at all?

Mariam Baghdasaryan 4F

Step 1. Atoms in their elemental state have an oxidation number of 0. Step 2. Atoms in monatomic (i.e. single atom) ions have an oxidation number equal to their charge. Step 3. In compounds: fluorine is assigned a −1 oxidation number; oxygen is usually assigned a −2 oxidation number (except in perox...

Mariam Baghdasaryan 4F

35. Calculate the wavelength of a 275 kg single-seat electric car traveling at a speed of 125 km.hr-1. Do electric cars have wavelike properties? A. λ = 6.94 x 10-38 m , Yes B. λ = 6.94 x 10-38 m , No C. λ = 1.93 x 10-38 m , Yes D. λ = 1.93 x 10-38 m , No I got the wavelength correct, but I chose A ...

Mariam Baghdasaryan 4F

37. Write the equation that allows one to calculate the electronic energy levels for the hydrogen atom. Do the calculated energies compare favorably with empirical observation (spectroscopic results)? C. E = -hR/(n2), No D. E = -hR/(n2), Yes Is the 2nd question asking whether the calculated version ...

Mariam Baghdasaryan 4F

25. Photoelectric experiments gave rise to a new equation relating the energy of light to its frequency. Select the right equation. A. λv = c B. Ek = mv2/2 C. mv2/2 = hv - φ D. E = hv E. None of the above Is E=hv the correct answer since it is the one that clearly relates energy to the frequency? I ...

Mariam Baghdasaryan 4F

If the electron went from a lower energy state (i.e. n to higher energy state that would indicate absorption, so the difference in energy would be positive instead of negative. Would the photon energy still be positive in this case since it is no longer an emission?

Mariam Baghdasaryan 4F

In the image, why is the photon of particular energy given as v? I understand that v=change in Energy/h, but isn't v the Bohr frequency condition and not "the particular energy"?

Mariam Baghdasaryan 4F

In the photoelectric effect, higher intensity does not necessarily mean greater amplitude right? Do we stop treating light like a wave once we consider it a photon?

Mariam Baghdasaryan 4F

Properties of Light: Friday 10/5 Lecture: When Professor Lavelle wrote v=m*s^-1 on the board was he referring to velocity? In my notebook, I wrote v as frequency, but I don't think that makes sense.

Mariam Baghdasaryan 4F

15. Calculate the concentration (molarity) of a glucose solution containing 0.1 moles of glucose in 0.4 liters of water. A. 0.25 mol.L-1 B. 4.0 mol.L-1 C. 2.5 mol.L-1 D. 2 mol.L-1 .1mol/.4L=.25 mol. L-1. So I got this for the answer but I was confused why the answer is exact and not 1 sig fig (.2)

Mariam Baghdasaryan 4F

18. For the following equation, determine the limiting reagent if 21.4 g NH3 is reacted with 42.5 g of O2. 4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g) A. NH3 B. O2 C. Both D. Neither I did this incorrectly the first time, so now I am not sure about my work. Can someone please confirm my work? Based on my...

Mariam Baghdasaryan 4F

0.0490 has 3 sig figs I read this in another post: "If the decimal point is present, start counting digits from the Pacific (left) side, starting with the first non-zero digit. If the decimal point is absent, start counting digits from the Atlantic (right) side, starting with the first non-zero...

Mariam Baghdasaryan 4F

The number of significant figures that the answer should have is determined by what is given in the question and not what has been calculated. Therefore, since the molar mass of 84 is the only number that is given, then the answer should have 2 significant figures because 84 has 2 sig figs. If ther...

Mariam Baghdasaryan 4F

19. The molar mass of cyclohexane is 84 g.mol–1 and its empirical formula is CH2 What is its molecular formula? So I did 1x12.011g.mol^-1+2x1.008g.mol^-1= 14.027g.mol^-1 When I do 84 g.mol–1/14.027g.mol^-1, how many sig figs will the answer have? Is 84 just considered an integer which means that I l...

Mariam Baghdasaryan 4F

So you are given 1.00 mol of Ag, but what you are supposed to find is the number of Ag atoms from this given info. because only then can you use the radius given (144pm) to figure out how long the fiber is. Step 1: you would convert the mol of Ag to number of Ag atoms 1.00 mol Ag x (6.0221x10^23)/mo...

Mariam Baghdasaryan 4F

If my empirical formula is CH2, for example, and then I need to use the molar mass to find the molecular formula, I do 1(12.011 g.mol^-1)+2(1.008 g. mol^-1). Will my answer have 3 places after the decimal because I am supposed to focus on the addition rule or will it be 4 significant digits because ...

Mariam Baghdasaryan 4F

I think the book defines N as "# of objects" because a "mole" is the amount of substance and that substance is Cu in your video. The objects that make up a substance can be atoms, molecules, ions, etc. In most examples, the "objects" are the atoms, so N is the # of atom...

CHEMISTRY COMMUNITY

Search found 37 matches

edta 4-

H20 as ligand

Ligand

Re: Question 4.91 Part B (Sixth Edition)

Re: Fall 2018 Final

Tetrahedral

Re: Determining Higher Boiling Points

Re: VESPR Geometric Shapes

Re: Seesaw bond angles

Re: End-to-end vs. Side-to-side

Re: Bond Angles

Repulsion Strength

Energy of Intermolecular forces

Re: Covalent Character

Re: Expanded Octet and Resonance

HW for this week

Re: Formal Charge SO42-

Formal Charge SO42-

Isoelectronic elements

Valence Electrons

Subshells

Re: Oxidation Numbers

De Broglie module #35

Atomic Spectra Module #37

Module: Photoelectric Effect #25

Absorption/atomic spectra

Atomic Spectra

Intensity

Friday 10/5 Lecture

Module: Molarity #15

Module Question #18 Help

Re: Sig Fig in Relation to Zero

Re: Empirical and Molecular Formula's Video #19

Empirical and Molecular Formula's Video #19

Re: Moles and Molar Mass

Sig Figs

Re: Clarification on Units (Moles)