Search found 45 matches

by BryantChung_4B
Mon Dec 02, 2019 2:40 am
Forum: Conjugate Acids & Bases
Topic: Conjugate acids and bases with lewis/bronsted acids
Replies: 3
Views: 44

Re: Conjugate acids and bases with lewis/bronsted acids

An acid is generally specific to its conjugate base, and a base is specific to its conjugate acid. Whether it is a Lewis or Bronsted base won't change what conjugate it forms.
by BryantChung_4B
Mon Dec 02, 2019 2:39 am
Forum: Conjugate Acids & Bases
Topic: Product of Acid and Base
Replies: 5
Views: 71

Re: Product of Acid and Base

In a reaction with acid containing hydrogen and a base containing hydroxide, the two will neutralize each other and give off their ions, meaning the H+ and OH- ions can now combine into H2O. The remaining ions can combine into a salt.
by BryantChung_4B
Mon Dec 02, 2019 2:35 am
Forum: Conjugate Acids & Bases
Topic: Conjugate/Bronsted/Lewis
Replies: 2
Views: 45

Re: Conjugate/Bronsted/Lewis

Lewis and Bronsted definitions have been explained above already, but just know that a conjugate base occurs when an acid donates an H+ and thus the product is now able to accept an H+ back in the reverse reaction.
by BryantChung_4B
Mon Dec 02, 2019 2:33 am
Forum: Conjugate Acids & Bases
Topic: Ligands
Replies: 12
Views: 114

Re: Ligands

Ligands are found in coordination compounds, meaning they donate an electron pair to a central atom.
by BryantChung_4B
Mon Dec 02, 2019 2:33 am
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 4
Views: 65

Re: Conjugate Acids and Bases

Conjugate acids and bases can arise in reversible reactions. For example, an acid donates an H+ to another molecule, and then turns into a product with one less H+. This is now a conjugate base, because in the reverse reaction, it can accept an H+.
by BryantChung_4B
Mon Nov 25, 2019 4:02 am
Forum: Coordinate Covalent Bonds
Topic: Electronegativity
Replies: 12
Views: 938

Re: Electronegativity

There are just certain periodic trends to know. In basic terms, electronegativity is mainly reliant on an atom's positive charge and the "shielding" of electrons. N is more electronegative than C because it has one more proton, allowing it to attract electrons more tightly. F is more elect...
by BryantChung_4B
Mon Nov 25, 2019 3:58 am
Forum: Coordinate Covalent Bonds
Topic: coordinate covalent bond
Replies: 5
Views: 504

Re: coordinate covalent bond

Some atoms can't complete their octet unless another atom donates a whole electron pair (2 electrons instead of 1). This is known as a coordinate covalent bond.
by BryantChung_4B
Mon Nov 25, 2019 3:57 am
Forum: Coordinate Covalent Bonds
Topic: carbon monoxide formal charges
Replies: 4
Views: 169

Re: carbon monoxide formal charges

Simple formal charge calculations. The carbon atom, for example, has 4 valence electrons, but if you take the electrons in a CO molecule (2 lone electrons and 3 bonded electron pairs) you will get 4 - 5 = -1 formal charge.
by BryantChung_4B
Mon Nov 25, 2019 3:55 am
Forum: Coordinate Covalent Bonds
Topic: Coordinate Covalent Bonds
Replies: 5
Views: 223

Re: Coordinate Covalent Bonds

Coordinate covalent bonds allow certain atoms to complete the octet. Boron, a big example, needs to accept a whole lone pair from another atom to complete its octet.
by BryantChung_4B
Mon Nov 25, 2019 3:53 am
Forum: Coordinate Covalent Bonds
Topic: Covalent character: BeCl2 Vs MgCl2
Replies: 4
Views: 1301

Re: Covalent character: BeCl2 Vs MgCl2

BeCl2. As stated, the molecule with smaller electronegativity difference has more covalent character. A larger difference becomes more ionic.
by BryantChung_4B
Fri Nov 22, 2019 12:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Specific Naming Question
Replies: 4
Views: 67

Re: Specific Naming Question

The electron geometry is considering all areas of electron density. Because this molecule has 5 such areas, it would be a trigonal bipyramidal shape. However, because one of the areas is a lone pair, the actual shape is a see-saw
by BryantChung_4B
Fri Nov 22, 2019 12:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Week 8 homework
Replies: 2
Views: 68

Re: Week 8 homework

Should be fine, it makes sense to do homework on whatever you studied.
by BryantChung_4B
Fri Nov 22, 2019 12:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Removing Non-Axis Atoms First
Replies: 4
Views: 73

Re: Removing Non-Axis Atoms First

The goal of the VSEPR model is showing how each region of electron density repels others. You do not always remove non-axis electrons first, it depends on whatever creates the farthest distance between each electron density region.
by BryantChung_4B
Fri Nov 22, 2019 12:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: NO Shape and Polarity
Replies: 4
Views: 72

Re: NO Shape and Polarity

Diatomic molecules like NO are always linear, as there's only one way to connect them. But this molecule is indeed polar because of the electronegativity difference between N and O.
by BryantChung_4B
Fri Nov 22, 2019 12:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape of Diatomic Molecules
Replies: 5
Views: 56

Re: Shape of Diatomic Molecules

The shape is always linear, just make sure not to confuse it with polarity. Diatomic molecules are not always nonpolar.
by BryantChung_4B
Sun Nov 17, 2019 6:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Angles
Replies: 4
Views: 70

Re: VSEPR Angles

Atomic radius only affects bond length. For VSEPR, you don't need to worry about atomic radius, just look at the areas of electron density.
by BryantChung_4B
Sun Nov 17, 2019 6:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 5
Views: 61

Re: Dipole moment

Dipole moment is just a term to describe attraction between molecules. Atoms in a molecule like H2O are unequal in electronegativity; the O atom pulls electrons more strongly, obtaining a partial negative charge, while the H atoms become partially positive. This creates a dipole.
by BryantChung_4B
Sun Nov 17, 2019 6:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: single, double, and triple bonds
Replies: 6
Views: 74

Re: single, double, and triple bonds

Whether the bond is single, double, or triple, it is still grouped as one area of electron density, so it can be treated the same as a different type of bond.
by BryantChung_4B
Sun Nov 17, 2019 6:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Prediction of Angles
Replies: 4
Views: 56

Re: Prediction of Angles

There are resources and charts to show the bond angles of specific shapes. The angles themselves though are determined by the areas of electron density repelling each other.
by BryantChung_4B
Sun Nov 17, 2019 6:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 3
Views: 55

Re: VSEPR

The basis of VSEPR is that areas of electron density repel each other and try to get as far from each other as possible. This repulsion determines the shape of the molecule and how the atoms are positioned.
by BryantChung_4B
Fri Nov 08, 2019 4:35 am
Forum: Electronegativity
Topic: Website
Replies: 3
Views: 98

Re: Website

You probably already tried, but just make sure you use LL14A19, which is the password he gave us.
by BryantChung_4B
Fri Nov 08, 2019 4:33 am
Forum: Formal Charge and Oxidation Numbers
Topic: Which lewis structure will make the dominant contribution to a resonance hybrid?
Replies: 5
Views: 75

Re: Which lewis structure will make the dominant contribution to a resonance hybrid?

If there can be a resonance structure with no formal charges on any atoms, that will be the most stable structure. However, if this is not possible, you would indeed place the charge on the more electronegative atom.
by BryantChung_4B
Fri Nov 08, 2019 4:31 am
Forum: Resonance Structures
Topic: Drawing the resonance hybrid
Replies: 2
Views: 57

Re: Drawing the resonance hybrid

The exam already passed but for future reference, it's good to draw the different resonance structures. Usually the question will ask for this.
by BryantChung_4B
Fri Nov 08, 2019 4:27 am
Forum: Lewis Structures
Topic: Midterm grades
Replies: 26
Views: 463

Re: Midterm grades

Like the above post says, probably about a week. It mostly depends on how fast the TA's will grade the tests.
by BryantChung_4B
Fri Nov 08, 2019 4:26 am
Forum: Octet Exceptions
Topic: radicals
Replies: 3
Views: 69

Re: radicals

One tip is that in most examples I've seen, the central atom will NOT have the single electron. This is not the specific rule, but we've learned that the central atom is least electronegative, so that one will not pull electrons as strongly as the outer, more electronegative atoms.
by BryantChung_4B
Sun Nov 03, 2019 7:19 am
Forum: Lewis Structures
Topic: Ion formation vs molecule
Replies: 2
Views: 39

Re: Ion formation vs molecule

The lowest energy is basically just a way of saying which bond is likely to form. NaCl, for example has a large electronegativity difference between Na and Cl, making it ionic.
by BryantChung_4B
Sun Nov 03, 2019 7:16 am
Forum: Resonance Structures
Topic: resonance hybrid vs resonance structure
Replies: 2
Views: 38

Re: resonance hybrid vs resonance structure

Resonance hybrid is how a molecule actually appears, when all the possible resonance structures are blended together.
by BryantChung_4B
Sun Nov 03, 2019 7:14 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge vs Actual Charge
Replies: 2
Views: 49

Re: Formal Charge vs Actual Charge

Yes, like the above student said, the numbers should add up to the charge of the actual molecule, showing that it is indeed the most favorable model.
by BryantChung_4B
Sun Nov 03, 2019 7:12 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charges
Replies: 3
Views: 43

Re: Formal Charges

The textbook includes formal charge numbers just to show which resonance structures would be more favorable, but it isn't required unless asked.
by BryantChung_4B
Sun Nov 03, 2019 7:10 am
Forum: Lewis Structures
Topic: Delocalized Electrons
Replies: 4
Views: 31

Re: Delocalized Electrons

The position of double bonds can change between resonance structures, because the electrons are not in a specific place but rather scattered around the atom. This is why they are called "delocalized."
by BryantChung_4B
Mon Oct 28, 2019 3:04 am
Forum: Lewis Structures
Topic: Orbitals
Replies: 9
Views: 114

Re: Orbitals

Yes, it might be confusing because 3d comes before it and d is higher energy, but you can just think of the highest shell (n = ...) as the outer layer to take electrons from.
by BryantChung_4B
Mon Oct 28, 2019 3:02 am
Forum: Electronegativity
Topic: Fluorine's Electronegativity
Replies: 6
Views: 117

Re: Fluorine's Electronegativity

Fluorine only has electrons in the n=2 shell, meaning there are no higher layers to "shield" the positive charge from attracting electrons. It also has the highest number of protons in its period, making the nucleus attract electrons very strongly.
by BryantChung_4B
Mon Oct 28, 2019 2:59 am
Forum: Electronegativity
Topic: Electronegativity in Covalent Bonds
Replies: 3
Views: 45

Re: Electronegativity in Covalent Bonds

Yes, but if you are referring to the electronegativity difference between two atoms, you can just know that ionic bonds happen when the electronegativity difference is greater than 1.6.
by BryantChung_4B
Mon Oct 28, 2019 2:57 am
Forum: Ionic & Covalent Bonds
Topic: periodic table
Replies: 10
Views: 123

Re: periodic table

Kennedi3K wrote:Is this the same for ionization energy?


Yes, if electronegativity increases, the nucleus attracts electrons more strongly, meaning the electrons are also harder to remove.
by BryantChung_4B
Mon Oct 28, 2019 2:55 am
Forum: Ionic & Covalent Bonds
Topic: Mnemonics for the period table trends
Replies: 3
Views: 40

Re: Mnemonics for the period table trends

I don't know any mnemonics, but I can try to help. If we're just talking about electron affinity, ionization energy, and atomic radius, you can just remember one: that atomic radius increases as you go to the left and downwards. The other 2 trends are just the opposite (IE and electron affinity incr...
by BryantChung_4B
Sun Oct 20, 2019 2:25 am
Forum: Trends in The Periodic Table
Topic: calculating the state
Replies: 3
Views: 45

Re: calculating the state

Px, Py, Pz just refers to the orientation of the P orbital, the subscript x, y, z, means that the orbital is positioned along whichever axis.
by BryantChung_4B
Sun Oct 20, 2019 1:03 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin up and spin down
Replies: 13
Views: 200

Re: Spin up and spin down

I'm not sure how to tell if an electron is in up or down spin state, but just know the spin quantum number (ms) can only be -1/2 or +1/2, meaning down spin and up spin respectively.
by BryantChung_4B
Sat Oct 19, 2019 3:57 pm
Forum: Quantum Numbers and The H-Atom
Topic: Electron Configuration
Replies: 2
Views: 61

Re: Electron Configuration

Yes, the quantum numbers tell you things like which subshell and orbital, using this information you can know the electron configuration.
by BryantChung_4B
Sat Oct 19, 2019 3:55 pm
Forum: Photoelectric Effect
Topic: One photon one atom interaction
Replies: 14
Views: 207

Re: One photon one atom interaction

It would increase. Simply increasing the intensity (or number) of photons will not eject more electrons, but increasing the frequency will.
by BryantChung_4B
Sat Oct 19, 2019 3:51 pm
Forum: Properties of Light
Topic: Problem 1A9. How to determine which values the reading event corresponds to?
Replies: 4
Views: 75

Re: Problem 1A9. How to determine which values the reading event corresponds to?

Basically looking at something is just processing visible light. Generally we know that visible light wavelengths range from about 400 to 700 nm, so 600 nm would be suitable for reading.
by BryantChung_4B
Fri Oct 04, 2019 9:42 am
Forum: Molarity, Solutions, Dilutions
Topic: Solutions vs. Dilutions
Replies: 4
Views: 94

Re: Solutions vs. Dilutions

As the others have stated, the difference between solution and dilution is almost like creation and modifying. Dilution is simply using a concentrated solution to create a less concentrated one.
by BryantChung_4B
Fri Oct 04, 2019 9:31 am
Forum: Balancing Chemical Reactions
Topic: PSA on L35 typo
Replies: 1
Views: 51

Re: PSA on L35 typo

Thank you for ur PSA!
by BryantChung_4B
Fri Oct 04, 2019 9:27 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15
Replies: 4
Views: 74

Re: E.15

You're given one thing: the molar mass of M(OH)2. We can subtract molar mass of (OH)2 from this to find the mass of M, the unknown metal. Next, the sulfide is simply the molecule after (OH)2 is replaced by a sulfur ion, becoming MS. You can just add the known mass of M to the mass of sulfur to find ...
by BryantChung_4B
Fri Oct 04, 2019 9:15 am
Forum: Significant Figures
Topic: Lab Sig Figs
Replies: 2
Views: 51

Re: Lab Sig Figs

I'm not completely sure, but there can be times where a constant is given like the speed of light c (3 x 10^8). In that case, you would not have to take into account that the constant only has 1 sig fig, it is just given to complete calculations.
by BryantChung_4B
Fri Oct 04, 2019 9:08 am
Forum: SI Units, Unit Conversions
Topic: Homework
Replies: 9
Views: 210

Re: Homework

I just wrote mine with pencil, as it wasn't really specified :)

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