Search found 50 matches

by Andrew Jang 4D
Sat Dec 07, 2019 11:15 pm
Forum: Bronsted Acids & Bases
Topic: List of Strong/Weak Acids/Bases
Replies: 2
Views: 83

Re: List of Strong/Weak Acids/Bases

There's a table on page F75 of the textbook that lists some common strong acids and bases
by Andrew Jang 4D
Fri Dec 06, 2019 3:38 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Weak/Strong acid
Replies: 1
Views: 35

Re: Weak/Strong acid

We don't need to know much about weak acids past the fact that they do not completely dissociate.
by Andrew Jang 4D
Fri Dec 06, 2019 3:23 pm
Forum: Hybridization
Topic: Lone pairs in hybridization
Replies: 4
Views: 86

Re: Lone pairs in hybridization

lone pairs do count as a region of electron density
by Andrew Jang 4D
Thu Dec 05, 2019 7:42 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty in Position
Replies: 1
Views: 109

Re: Uncertainty in Position

If they give a radius value or a +/- value you should multiply by 2
by Andrew Jang 4D
Sun Dec 01, 2019 5:26 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Content of the final
Replies: 10
Views: 404

Re: Content of the final

i don't recall learning about either topic and i'd assume whatever isn't taught by wednesday isn't on the final
by Andrew Jang 4D
Sun Dec 01, 2019 5:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelate complex
Replies: 1
Views: 23

chelate complex

what is the significance of a chelate complex?
by Andrew Jang 4D
Sun Dec 01, 2019 5:17 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH scale
Replies: 12
Views: 104

Re: pH scale

I would assume that pH values of 0-14 are the most commonly found
by Andrew Jang 4D
Sun Dec 01, 2019 5:09 pm
Forum: Industrial Examples
Topic: Biological examples of co-ordination compounds
Replies: 3
Views: 101

Re: Biological examples of co-ordination compounds

I feel like being conceptually aware of the significance of coordination compounds in biology will be more useful than memorizing specific examples. I do remember him talking about cisplatin and how it's an important chemo drug as it forms a coordination compound w/ DNA to stop replication.
by Andrew Jang 4D
Sun Dec 01, 2019 5:05 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: structure of water
Replies: 4
Views: 37

structure of water

Water has 2 lone pairs - why is it monodentate?
by Andrew Jang 4D
Sun Dec 01, 2019 4:52 pm
Forum: Lewis Acids & Bases
Topic: bronsted vs lewis
Replies: 9
Views: 83

Re: bronsted vs lewis

think of bronsted in terms of H+ ion donors/acceptors and lewis in terms of electron donors/acceptors.
by Andrew Jang 4D
Sun Nov 24, 2019 11:16 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating complexes
Replies: 4
Views: 27

Re: Chelating complexes

I believe a chelating complex is a coordination complex with a central metal atom bound to a ligand that forms a ring structure
by Andrew Jang 4D
Sun Nov 24, 2019 11:13 am
Forum: Naming
Topic: Naming coordination compound
Replies: 1
Views: 30

Re: Naming coordination compound

would it be hexaamminecobalt (II) chloride?
by Andrew Jang 4D
Fri Nov 22, 2019 7:52 pm
Forum: Bronsted Acids & Bases
Topic: Strong vs Weak Acids
Replies: 3
Views: 48

Re: Strong vs Weak Acids

strong acids completely dissociate in water while weak acids do not.
by Andrew Jang 4D
Fri Nov 22, 2019 5:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: transition metals
Replies: 3
Views: 36

transition metals

what is the importance of transition metals having many different oxidation states?
by Andrew Jang 4D
Sun Nov 17, 2019 9:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial lone pairs
Replies: 2
Views: 24

Equatorial lone pairs

Why does the lone pair in a seesaw shape have to come from the equatorial plane?
by Andrew Jang 4D
Sun Nov 17, 2019 9:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 10
Views: 70

Re: Lone Pairs

Lone pairs cause repulsion, so the shape of a molecule is determined by minimizing the repulsive forces; this leads to particular arrangements that are most suited.
by Andrew Jang 4D
Sun Nov 17, 2019 9:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone vs. Bonded Electrons
Replies: 3
Views: 32

Re: Lone vs. Bonded Electrons

The shape of the lone pair orbital is different than the shape of a bonding electron orbital, and this shape causes greater repulsion.
by Andrew Jang 4D
Sun Nov 17, 2019 2:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Structure of H2O
Replies: 3
Views: 39

Structure of H2O

I remember in lecture Dr. Lavelle said lone pairs in molecules are usually opposite each other due to the high repulsion. Why is this not the case for water?
by Andrew Jang 4D
Sun Nov 17, 2019 2:00 pm
Forum: Hybridization
Topic: Pi vs Sigma Bonds
Replies: 10
Views: 77

Re: Pi vs Sigma Bonds

The orbitals involved in forming sigma bonds overlap more than the orbitals involved in forming pi bonds. This increased overlapping of orbitals makes sigma bonds relatively stronger because it creates shorter and therefore stronger bonds.
by Andrew Jang 4D
Mon Nov 11, 2019 2:23 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: melting points
Replies: 6
Views: 50

melting points

why is H2O's melting point 0 degrees C while H2S has a melting point of -86 degrees C?
by Andrew Jang 4D
Mon Nov 11, 2019 2:22 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Comparison
Replies: 1
Views: 23

Re: Comparison

Intramolecular forces hold atoms together in a molecule while intermolecular forces are forces between different molecules
by Andrew Jang 4D
Mon Nov 11, 2019 12:56 am
Forum: Dipole Moments
Topic: Hydrogen bonds
Replies: 17
Views: 147

Hydrogen bonds

are H bonds only formed between molecules with N, O, and F atoms or can other molecules that lack these specific elements form H bonds
by Andrew Jang 4D
Mon Nov 11, 2019 12:51 am
Forum: Determining Molecular Shape (VSEPR)
Topic: H2O and Ionic Compounds
Replies: 3
Views: 37

Re: H2O and Ionic Compounds

Due to its polarity, water dissociates ionic compounds that have a negatively and positively charged anion and cation, respectively.
by Andrew Jang 4D
Mon Nov 11, 2019 12:49 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Diatomic Molecules
Replies: 6
Views: 46

Re: Diatomic Molecules

because two different elements will have slightly different electronegativities
by Andrew Jang 4D
Sun Nov 03, 2019 11:27 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 3
Views: 50

Re: Electron Configuration

the highest orbital usually has the highest energy so the atom wants to get rid of the electron
by Andrew Jang 4D
Sun Nov 03, 2019 11:18 pm
Forum: Quantum Numbers and The H-Atom
Topic: magnetic quantum number
Replies: 5
Views: 48

magnetic quantum number

What exactly does the magnetic quantum number describe?
by Andrew Jang 4D
Sun Nov 03, 2019 11:01 pm
Forum: Resonance Structures
Topic: Drawing the resonance hybrid
Replies: 2
Views: 50

Re: Drawing the resonance hybrid

During a review session today the guy said you could either draw the resonance hybrid or draw the different resonance structures and explain that they contribute to the hybrid structure
by Andrew Jang 4D
Sat Nov 02, 2019 2:48 pm
Forum: Ionic & Covalent Bonds
Topic: covalent character of ionic bonds
Replies: 4
Views: 47

covalent character of ionic bonds

Can someone explain how all ionic bonds have varying amounts of covalent character?
by Andrew Jang 4D
Sat Nov 02, 2019 2:44 pm
Forum: Lewis Structures
Topic: Midterm Topics
Replies: 8
Views: 72

Re: Midterm Topics

i think it's everything until interionic/intermolecular attractive forces will be on the midterm
by Andrew Jang 4D
Sun Oct 27, 2019 1:53 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent bonds
Replies: 5
Views: 75

Re: Covalent bonds

Metals usually don't form covalent bonds because they have low ionization energies, so it's easier for them to release a few electrons in order to become more stable as opposed to sharing electrons.
by Andrew Jang 4D
Sun Oct 27, 2019 11:27 am
Forum: Octet Exceptions
Topic: expanded valence shells
Replies: 4
Views: 32

Re: expanded valence shells

They have a d orbital that can accommodate more electrons for bonding as opposed to period 1 or 2 elements that are limited to s and p orbitals
by Andrew Jang 4D
Sat Oct 26, 2019 8:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Shortcut
Replies: 3
Views: 49

Re: Electron Configuration Shortcut

You should remember that when doing electron configuration, the orbitals get filled by order of energy. Since the 4s orbital has lower energy than the 3d orbital it is filled first (save for a few exceptions).
by Andrew Jang 4D
Sat Oct 26, 2019 8:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework Problem 1E.13
Replies: 3
Views: 59

Re: Homework Problem 1E.13

The f-block is included because, according to the Aufbau Principle, after the 6s oribtal the 4f orbital is filled. Elements 57-71 are called the f-block elements due to their electron configurations, so the f orbital is included for tungsten because it comes after these f-block elements.
by Andrew Jang 4D
Thu Oct 24, 2019 10:06 pm
Forum: Ionic & Covalent Bonds
Topic: ground-state configuration of ions
Replies: 4
Views: 48

Re: ground-state configuration of ions

for a) could it be because it's Cu^+ and not just Cu, so you lose an electron?
by Andrew Jang 4D
Sat Oct 19, 2019 3:12 pm
Forum: DeBroglie Equation
Topic: 1B.15 a
Replies: 4
Views: 49

Re: 1B.15 a

The mass of an electron is given in the back of the textbook in the "fundamental constants" section. I think we're expected to use that in any problems that involve electron mass in some way.
by Andrew Jang 4D
Sat Oct 19, 2019 3:09 pm
Forum: DeBroglie Equation
Topic: 1B.9 HW prob
Replies: 2
Views: 35

Re: 1B.9 HW prob

The question says that the lamp is rated at 32 W or 32 J/s, and it asks for how many photons of light it generates in 2.0 seconds. 32 J/s * 2 s = 64 J. This is where that value comes from.
by Andrew Jang 4D
Sat Oct 19, 2019 3:06 pm
Forum: Photoelectric Effect
Topic: hw 1B.15 part c
Replies: 3
Views: 68

Re: hw 1B.15 part c

You should find the energy of the photon that caused the electron to eject as well as move at 3.6*10^3 km/s. You already found the energy required to eject the electron from the metal surface in part B, so all you need now is the kinetic energy of the electron that makes it move at its speed. You ca...
by Andrew Jang 4D
Sat Oct 19, 2019 3:00 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions (Cr and Cu)
Replies: 2
Views: 46

Re: Exceptions (Cr and Cu)

In both Cr and Cu, the 4s sublevel is 4s1 when we expect it to be 4s2. This is because electrons want to be at the lowest energy possible in order to be stable, and moving the electron from the 4s sublevel to the 3d sublevel to produce either an exactly half filled sublevel (for Cr) and a full suble...
by Andrew Jang 4D
Fri Oct 18, 2019 4:26 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Noble Gas Shortcut
Replies: 3
Views: 39

Re: Noble Gas Shortcut

You use the noble gas that's the closest one before the element you are describing, and I'm pretty sure you can just do [Ar] for argon.
by Andrew Jang 4D
Sat Oct 12, 2019 8:45 pm
Forum: Properties of Light
Topic: How does x-ray crystallography work?
Replies: 2
Views: 34

Re: How does x-ray crystallography work?

X-ray diffraction is used to determine the structure of a crystallized substance. An x-ray beam will diffract from the crystal, and the resulting angles and intensities are measured, helping form a 3-D model of atomic structure.
by Andrew Jang 4D
Sat Oct 12, 2019 6:58 pm
Forum: Properties of Electrons
Topic: Balmer and Lyman Series
Replies: 3
Views: 85

Balmer and Lyman Series

In 1A.11, it asks "what is common to the lines within a series that makes grouping them together logical?" and I was wondering what they're looking for. Is the fact that the lower energy level is always n=1 for Lyman and n=2 for Balmer what groups them together?
by Andrew Jang 4D
Sat Oct 12, 2019 6:40 pm
Forum: SI Units, Unit Conversions
Topic: Weekly Posts
Replies: 7
Views: 99

Re: Weekly Posts

Since it's a weekly assignment I would try to get your 5 posts in before Sunday but I'm not 100% sure if it has to be by tonight.
by Andrew Jang 4D
Sat Oct 12, 2019 6:35 pm
Forum: Einstein Equation
Topic: 1B.15
Replies: 2
Views: 64

Re: 1B.15

For part (a), you can use De Broglie’s equation to find the wavelength, which is wavelength=h/mv. Using the mass of an electron for m and its velocity for v, we can plug in and solve for the wavelength.
by Andrew Jang 4D
Fri Oct 11, 2019 3:39 pm
Forum: Properties of Electrons
Topic: Circular Standing Wave
Replies: 3
Views: 58

Re: Circular Standing Wave

If you remember the wave model pictures he showed us where the peaks and troughs overlapped in a circle, the line representing the wave didn’t connect if the energy level wasn’t n=1,2,3,4….etc because it isn’t stable.
by Andrew Jang 4D
Thu Oct 03, 2019 12:25 am
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental G.13
Replies: 4
Views: 64

Re: Fundamental G.13

The florist dilutes the 1.0 L of 0.20 M NH4NO3 with water, so the amount of moles of NH4NO3 is unchanged; the molarity changes from 0.20 M to 0.05 M because the volume goes from 1.0 L to 4.0 L. Each plant receives 100. mL, or 0.1 L, of solution, meaning they receive 0.005 mol of NH4NO3. In each mole...
by Andrew Jang 4D
Thu Oct 03, 2019 12:16 am
Forum: SI Units, Unit Conversions
Topic: E1
Replies: 3
Views: 33

E1

The book gives the solution in km, but the radius was given in pm. Is it acceptable to leave your answer in terms of pm or should it be converted to a unit that is more commonly used in chemistry?
by Andrew Jang 4D
Tue Oct 01, 2019 11:27 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Lecture Question
Replies: 5
Views: 142

Re: Limiting Reactant Lecture Question

It definitely is possible to have no limiting reactants but highly unlikely. If in the reaction A+B➝C+D you had exactly 1.00 mol of reactants A and B, they would both be used up completely. However, a mol is 6.02*10^23 particles and it would be extremely hard to measure exactly that amount out for b...
by Andrew Jang 4D
Tue Oct 01, 2019 1:50 pm
Forum: SI Units, Unit Conversions
Topic: Homework Q about finding the sulfide of a metal
Replies: 1
Views: 67

Re: Homework Q about finding the sulfide of a metal

This question requires you to identify the unknown metal M in the metal hydroxide M(OH)2. Subtracting the mass of the (OH)2 part from the total mass given leaves you with a value of about 40.1 g as the molar mass of M. You can find that Ca has a molar mass of about 40.1 g, and its sulfide, CaS, has ...
by Andrew Jang 4D
Tue Oct 01, 2019 12:21 am
Forum: SI Units, Unit Conversions
Topic: Writing Compound Formulas
Replies: 3
Views: 69

Re: Writing Compound Formulas

It’s very easy to panic when you’re asked to write the formula of some compound that has a long and unfamiliar name; this was my Achilles heel in high school chemistry and I struggled due to not being able to write these out. However, it’s not as bad as I initially thought! Like the previous replies...

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