CHEMISTRY COMMUNITY

juliefilice 4A

The molar concentration of HCl in hydrochloric acid is reduced to 12% of its initial value by dilution. What is the difference in pH values of the two solutions?
Can someone please help me out on how to start this problem?

juliefilice 4A

Yes, HN(CH2CH2NH2) is tridentate. It's easier to see when looking at the structure drawn out, but there are 3 N atoms each with a set of lone pairs that are ready to form a coordinate covalent bond. The ligand bends in such a way to where the N atoms are able to bind to the same metal atom.

juliefilice 4A

Yup! An anionic complex with an overall negative charge.

juliefilice 4A

You have the right idea. Polydentate means one ligand can bind to the same metal atom at different binding sites. The chelate is the complex that is produced when a polydentate ligand binds to a metal atom and forms a ring. Chelation is just this process, and the polydentate ligand can be referred t...

juliefilice 4A

Why is the PF bond in PF3 longer than the NF bond in NF3? This is from homework problem 2.25

juliefilice 4A

How does ClF3 have a dipole moment? Does it have to do with the lone pairs on the Cl molecule?

juliefilice 4A

How do we decide whether aqueous solutions of salts are acidic, neutral, or basic? Could someone please explain how Ba(NO2)2 would be basic?

juliefilice 4A

Thank you Sam that was super helpful!

juliefilice 4A

Lavelle said in class that we can use the charge of the ligands to figure out the oxidation number of the central atom. He used the example Fe(CN)6^4- with an oxidation number or 2+. How do we know the charge of the CN molecules?

juliefilice 4A

What is the "s-character" of a hybridized atom?

juliefilice 4A

But which is the correct way to arrange the atoms?

juliefilice 4A

The bonding electron pair shared in a sigma bond with an adjacent atom lies further from the central atom than a nonbonding (lone) pair of that atom, which is held close to its positively charged nucleus. Thus, repulsion from a lone pair is greater than repulsion from a bonding pair.

juliefilice 4A

Hybridization occurs because electrons in an atom or molecule are randomly dispersed, and sometimes happen to be gathered in one area. This causes dipole dispersion, and another dipole molecule interacts with these electrons making Van Der Waals forces. The atomic orbitals overlap (hybridization) to...

juliefilice 4A

We represent molecules using 2D Lewis structures, but they really exist in 3D space. This means that the atoms can get father away from each other, going behind or coming in front of the central atom, which explains the larger bond angle of 109.5

juliefilice 4A

Professor Lavelle said that for a bond to be considered ionic, the difference in electronegativites of the 2 atoms should be at least 2. This isn't the case for BeBr2, so it's not ionic.

juliefilice 4A

Why isn't BeBr2 an ionic compound?

juliefilice 4A

A bond will be polar covalent if the 2 atoms have different electronegativities. In the case of C and H, they have similar enough electronegativities (I think theres a .3 difference) to be non polar covalent. C and H are the 2 main elements you need to know have similar electronegativities.

juliefilice 4A

Basically, elements on the left half of the periodic table will have +1/2, and elements on the right half will have -1/2. This is because on the left half of the table, the orbitals each have one electron in them, and once you get to the other half, the electrons begin to double up. Each element has...

juliefilice 4A

Why doesn't the 13th column of the periodic table need an octet?

juliefilice 4A

When talking about Lewis acids and bases, Lavelle drew the Lewis structure for BF3 with Boron only having 6 electrons. He explained this was because making one of the B-F bonds a double bond would give F a + charge. Why would that be a bad thing?

juliefilice 4A

In lecture, Dr. Lavelle drew out the Lewis structures for NO3- when explaining resonance. Nitrogen has 2 single bonds to Oxygen and one double bond to Oxygen, but I thought Nitrogen could only make 3 bonds because it has 5 valence electrons. Can someone please explain how this works? Can we just add...

juliefilice 4A

The electron configuration for each of these atoms is listed on the periodic table. So for (a) Zn, the electron configuration is [Ar] 3d10 4s2. To form a +1 ion, an electron will be taken from the outermost shell, which we get from the electron configuration. For Zn, an electron would be removed fro...

juliefilice 4A

Energy and intensity aren't the same in practice. You first find the total energy (32W*1J/s*2s=64J), then find the energy per photon using E=hc/lambda. Calculate the number of photons by dividing the total energy by the energy/photon, then convert this number to moles by dividing by Avogadro's numbe...

juliefilice 4A

The question reads, "In each second, a certain lamp produces 2.4x10^21 photons with a wavelength of 633 nm. How much power (in watts) is produced as radiation at this wavelength?" I know how to solve this problem and that you start using E=hc/lambda, but do I need to convert the wavelength...

juliefilice 4A

We write electron configurations for the ground state, so yes it would be 1s1 for H and 1s2 for He. An excited H electron will pass all energy levels up to the one matching the energy of the photon, and then fall right back down to release the energy as light.

juliefilice 4A

Yes, the SI unit for mass is kg. However, in many problems, we're dealing with amounts of samples that make most sense to express in g. In a realistic lab setting we would say 2.4 g instead of 2.4 x 10^-3 kg. So if a problem gives units in g, it's probably best to use g in your answer

juliefilice 4A

why is the ionization energy for O lower than that of N or F when ionization energy usually increases from left to right across the periodic table?

juliefilice 4A

Can someone please explain how to write the ground state electron configuration of atoms: sodium, silicon, chlorine, and rubidium?

juliefilice 4A

classical mechanics explains behavior of large objects, while quantum mechanics describes very small objects, such as subatomic particles. In his example during class, he described water in both ways. In a classical sense, when we pour water from a can, it comes out as one continuous stream. However...

juliefilice 4A

Could I get a step by step solution to this problem? I'm not sure where to start. "A 1.50 g sample of metallic tin was placed in a 26.45 g crucible and heated until all the tin had reacted with the O in air to form an oxide. The crucible and product together were found to weigh 28.35 g. a. What...

juliefilice 4A

Will we need to know the molar masses of elements for tests? I know the basics (O,C,H,N), but am wondering if I should try to memorize any others or if we'll be given a periodic table.

CHEMISTRY COMMUNITY

Search found 31 matches

homework problem 6B.1

Re: 7th edition 9C.5

Re: Cation Naming

Re: Polydentate v. Chelate

bond length

Net Dipole

aqueous solutions of salts

Re: Ligand charge

Ligand charge

s-character

Re: 2E.25 (7th ed)

Re: Repulsion Strength

Re: General definition/context

Re: Bond Angles

Re: 7th edition 2D.3

Covalent or ionic?

Re: Non-polar and Polar Covalent Bonds

Re: Quantum Numbers related to Orbitals

Re: Octet Exceptions

Boron Trifluoride class example

Lewis Structure NO3-

Re: Chemical Bonds 3.13

Re: 1B.9 (7th edition)

unit conversion hw Q 1.3

Re: Question about H electron configuration

Re: What Unit of Mass to Use?

problem 1.13

Orbitals problem 1E.11

Re: Classical vs Quantum

Question L.39, Reaction Stoichiometry

Molar Masses