Search found 51 matches

by Natalie Wang 1B
Sun Dec 08, 2019 10:56 pm
Forum: General Science Questions
Topic: Aqueous
Replies: 3
Views: 158

Re: Aqueous

Aqueous molecules disassociate in water. Also, you should only use the concentrations of aqueous compounds when calculating the Ka or Kb.
by Natalie Wang 1B
Sun Dec 08, 2019 10:55 pm
Forum: Amphoteric Compounds
Topic: As2O3
Replies: 3
Views: 89

Re: As2O3

It's a good rule of thumb to know that elements near the metalloids will form amphoteric salts. For example, aluminum oxide will form an amphoteric salt.
by Natalie Wang 1B
Sun Dec 08, 2019 10:53 pm
Forum: Biological Examples
Topic: Biological Function
Replies: 2
Views: 81

Re: Biological Function

Cis platinum chelates a nitrogenous base and blocks DNA replication.
by Natalie Wang 1B
Sun Dec 08, 2019 10:52 pm
Forum: General Science Questions
Topic: Final : Question about Neutral or Ionized acid
Replies: 3
Views: 195

Re: Final : Question about Neutral or Ionized acid

Another way to think about it is that in the pH of 2, there are a lot of H+ ions. In equilibrium reactions, which is what happens when weak acids disassociate, an equilibrium must be maintained. Since there are a lot of H+ ions, this would cause the reaction to favor the opposite end of the acid dis...
by Natalie Wang 1B
Sat Dec 07, 2019 2:12 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6.21
Replies: 1
Views: 35

6.21

In 6.21 c, it asks to mark the amphiprotic areas of Thymine. According to the solutions manual, the Nitrogen atoms are amphiprotic. Why is that? Can someone explain this to me?
by Natalie Wang 1B
Sun Dec 01, 2019 9:27 pm
Forum: Octet Exceptions
Topic: Why can't Aluminum have an expanded octet?
Replies: 5
Views: 170

Re: Why can't Aluminum have an expanded octet?

As everyone else has said, Aluminum can have less than the octet rule. Boron is another important element that can have less than the octet rule.
by Natalie Wang 1B
Sun Dec 01, 2019 9:25 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: AXE formula
Replies: 32
Views: 2606

Re: AXE formula

Yes, the AXE formula is part of VSEPR Theory, which is used to determine a molecule's shape. Just remember that you can't use hybridization to determine a molecule's shape!
by Natalie Wang 1B
Sun Dec 01, 2019 9:23 pm
Forum: Hybridization
Topic: Hybridization of Carbon and Nitrogen
Replies: 2
Views: 37

Re: Hybridization of Carbon and Nitrogen

For CH20, carbon will have a sp2 hybridization because it has a single bond for each H atom and a double bond with the O atom. Carbon will only have 3 electron densities, which correlates with sp2.
by Natalie Wang 1B
Sun Dec 01, 2019 9:21 pm
Forum: Hybridization
Topic: 2F. 15 General Pattern?
Replies: 2
Views: 35

Re: 2F. 15 General Pattern?

I agree. I believe that s character is referring to the role of the s orbital in the hybridization. An sp2 hybridized orbital would have more s character than an sp3 hybridized orbital. And, as we know from molecular structures, a structure with sp3 hybridized orbitals (like a tetrahedral molecule) ...
by Natalie Wang 1B
Sun Dec 01, 2019 9:15 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Homework question 9C.7
Replies: 2
Views: 58

Re: Homework question 9C.7

The answer would be b. The two NH2 molecules are close to each other, so a metal atom can be drawn between them, forming a bidentate ligand, which would be a chelate. Here is an image address to what I mean: https://ars.els-cdn.com/content/image/3 ... 186880.jpg
by Natalie Wang 1B
Sun Nov 24, 2019 9:01 pm
Forum: Hybridization
Topic: How to Determine Hybridization
Replies: 2
Views: 28

Re: How to Determine Hybridization

Molecules have hybridizations to form enough bonds. For example, CH4 has hybridization because normally C only has 2 unpaired electrons. With an sp3 hybrdization, C has 4 unpaired electrons that can bond with 4 H's. On the other hand, hybridization can also ensure the stability of a molecule. For ex...
by Natalie Wang 1B
Mon Nov 18, 2019 11:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: seesaw
Replies: 5
Views: 62

Re: seesaw

I asked my TA, and he said that the angles will be less than 120 and 90.
by Natalie Wang 1B
Mon Nov 18, 2019 11:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 5
Views: 45

Re: polarity

I was really confused about this too, but I highly recommend that you watch this Youtube video to contextualize the answer: https://www.youtube.com/watch?v=As-hcYY8Yaw Start at the the 5 minute mark. To give you a written answer, CH2Cl2 is polar because of the bond angles. Remember that a tetrahedra...
by Natalie Wang 1B
Mon Nov 18, 2019 11:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E29
Replies: 1
Views: 23

Re: 2E29

For the first part of the question, think about symmetry. If the two chlorine bonds are right across from each other, their dipole moments will cancel each other out. Therefore, Form 3 is nonpolar. Form 1 and Form 2 don't have the chlorine atoms straight across each other, so their dipole moments do...
by Natalie Wang 1B
Sun Nov 17, 2019 9:34 pm
Forum: Hybridization
Topic: 2F.5
Replies: 1
Views: 10

Re: 2F.5

I'm not sure why the answer is like that. But there is no way that Boron could have a lone pair. The hybridization should just be sp3.
by Natalie Wang 1B
Sun Nov 17, 2019 9:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma vs pi bonds
Replies: 2
Views: 28

Re: Sigma vs pi bonds

I don't think sigma and pi bonds really affect VSEPR. VSEPR involves where regions where there are valence electrons. If there are only 2 areas where valence electrons can be found, the molecule is linear. If there are only 3 areas where valence electrons can be found, the molecule is trigonal plana...
by Natalie Wang 1B
Sun Nov 17, 2019 9:26 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Dispersion Forces
Replies: 3
Views: 37

Re: Dispersion Forces

Dispersion forces are stronger for bigger molecules. Therefore, a molecule with atoms of bigger atomic radii will have stronger dispersion forces.
by Natalie Wang 1B
Sun Nov 17, 2019 9:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E. 27
Replies: 3
Views: 28

Re: 2E. 27

If the molecule is asymmetrical, it will be polar. Therefore, for example, CHCl3 would be polar because the H makes it asymmetrical.
by Natalie Wang 1B
Sun Nov 10, 2019 11:17 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Lattice Energy
Replies: 2
Views: 20

Re: Lattice Energy

If the solid has strong intermolecular forces, the lattice energy will increase. The lattice energy is basically the amount of energy requires to break those connections between molecules. As a result, strong intermolecular forces increase lattice energy.
by Natalie Wang 1B
Sun Nov 10, 2019 11:12 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: dipole dipole of H2SeO4
Replies: 1
Views: 26

Re: dipole dipole of H2SeO4

Se is in the middle of two OH groups and two double bonded O atoms. Each bond has dipole moment since there is a substantial difference in electronegativity between Se and each O it is bonded to. If you are wondering why H2SeO4 might be a polar molecule, I saw a post that has a similar topic to that...
by Natalie Wang 1B
Sun Nov 10, 2019 11:06 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Hydrocarbons at room temperature
Replies: 2
Views: 19

Re: Hydrocarbons at room temperature

The bigger a hydrocarbon, the stronger the intermolecular bonds are. In dispersion forces, more electrons means larger dispersion forces. That explains why bigger molecules have stronger dispersion forces.
by Natalie Wang 1B
Sun Nov 10, 2019 11:02 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: 3F. 3
Replies: 2
Views: 30

Re: 3F. 3

Dipole-dipole interactions occur between polar molecules. For the answer, choose the molecules that have an overall polarity. The asymmetrical molecules will be polar.
by Natalie Wang 1B
Sun Nov 10, 2019 10:59 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: forces and boiling points
Replies: 6
Views: 32

Re: forces and boiling points

When there are more electrons, London (Dipole-dipole/Dispersion) Forces are stronger. CCl4 has more electrons than CH4, so it has stronger intermolecular forces.
by Natalie Wang 1B
Sun Nov 03, 2019 6:54 pm
Forum: Octet Exceptions
Topic: 2C.5
Replies: 2
Views: 36

Re: 2C.5

To simplify radicals, just look at the total valence electrons of the molecule. If the total is even, the molecule is not radical. If the total is odd, the molecule is radical.
by Natalie Wang 1B
Sun Nov 03, 2019 6:52 pm
Forum: Lewis Structures
Topic: Central Atom
Replies: 3
Views: 30

Re: Central Atom

The central atom is usually the atom with the least ionization energy. Of course if the molecule has hydrogen, hydrogen can't be the central atom. For the Lewis Structure, it is important for the central atom to have 0 formal charge.
by Natalie Wang 1B
Sun Nov 03, 2019 6:51 pm
Forum: Lewis Structures
Topic: Radicals
Replies: 5
Views: 84

Re: Radicals

For most molecules, the atom that gets the extra electron is the one that that already has other lone pairs. Of course, for problem 5a from Focus 2C, there is a molecule that is ClO. The extra electron is put onto Cl. I think it is likely because Cl is more electronegative. But also, it makes Cl's f...
by Natalie Wang 1B
Sun Nov 03, 2019 6:43 pm
Forum: Lewis Structures
Topic: lone pairs versus double bonds
Replies: 2
Views: 31

Re: lone pairs versus double bonds

Usually lone pairs are used to satisfy the total amount of valence electrons in the molecule. Otherwise, if you are dealing with a molecule with an atom from period 3 (or beyond) as the central atom (atoms that are exceptions to the octet rule), having lone pairs might bring their formal charges to ...
by Natalie Wang 1B
Sun Nov 03, 2019 6:39 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 14
Views: 169

Re: Ionic vs Covalent

The difference is their electronegativity. If the electronegativity between the two atoms is more than 2.5, the bond is ionic. If the electronegativity between the two atoms is less than 1.5, the bond is covalent. Between 1.5 and 2.5, the bond has ionic and covalent components.
by Natalie Wang 1B
Sun Oct 27, 2019 1:49 pm
Forum: Octet Exceptions
Topic: Reasoning behind the exceptions
Replies: 3
Views: 67

Re: Reasoning behind the exceptions

Actually, Aluminum usually donates its valence electrons to have an octet (Al+3).
by Natalie Wang 1B
Sun Oct 27, 2019 1:47 pm
Forum: Resonance Structures
Topic: formal charge
Replies: 3
Views: 53

Re: formal charge

Having a 0 formal charge is the most stable, so the Sulfur has a 0 formal charge. Of course, this causes two of the oxygen atoms bonded to sulfur to each have a formal charge of -1. This is fine because oxygen is already more electronegative than sulfur, so it attracts the electrons more. Even thoug...
by Natalie Wang 1B
Sun Oct 27, 2019 1:44 pm
Forum: Resonance Structures
Topic: Exceptions For Drawing Structures
Replies: 1
Views: 27

Re: Exceptions For Drawing Structures

Some exceptions to remember:
1. H, He, Li, and Be are exceptions to the Octet rule. That means they don't need 8 valence electrons.
2. P, S, and Cl can have more than 8 valence electrons. For example, in phosphorous pentachloride, phosphorous has 10 electrons.
by Natalie Wang 1B
Sun Oct 27, 2019 1:38 pm
Forum: Lewis Structures
Topic: bond lengths
Replies: 2
Views: 30

Re: bond lengths

Also, double bonds are stronger than single bonds, so they require more energy to break.
by Natalie Wang 1B
Sun Oct 27, 2019 1:38 pm
Forum: Lewis Structures
Topic: Bond Lengths
Replies: 2
Views: 37

Re: Bond Lengths

This rule applies to all bonds between all atoms. Generally, single bonds are longer than double bonds.
by Natalie Wang 1B
Sun Oct 20, 2019 4:52 pm
Forum: Student Social/Study Group
Topic: Study Group Fall 2019
Replies: 32
Views: 1668

Re: Study Group Fall 2019

Hi everybody, I made a groupme if anyone is interested! I'll probably post it on facebook, too.
https://app.groupme.com/join_group/55046813/XcQgQkkM
by Natalie Wang 1B
Sun Oct 20, 2019 4:48 pm
Forum: Properties of Electrons
Topic: Hund's Rule
Replies: 5
Views: 84

Re: Hund's Rule

I like to think Hund's Rule as a school bus. When you enter a bus, you would rather take the empty seat than sit next to someone else. This can apply to electrons in each subshell of an orbital. The subshells need to each have 1 electron before there can be two electron in each subshell.
by Natalie Wang 1B
Sun Oct 20, 2019 4:44 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty value
Replies: 4
Views: 47

Re: Uncertainty value

Actually, I saw on a recent post that if it is + - n, the uncertainty is 2n. Therefore, the uncertainty of this should be 10 mm, I think.
by Natalie Wang 1B
Sun Oct 20, 2019 4:41 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Purpose of the Equation
Replies: 9
Views: 89

Re: Purpose of the Equation

Yes! The uncertainty of momentum and the uncertainty of position are indirectly proportional. If you change the equation, you will see that:
p >= h/(4pi *x)
You can see that p is proportional to 1/x. So if p goes up, then x needs to go down and vice versa.
by Natalie Wang 1B
Sun Oct 20, 2019 4:37 pm
Forum: *Shrodinger Equation
Topic: Hamiltonian
Replies: 6
Views: 68

Re: Hamiltonian

The Hamiltonian is the double derivative or the wave function (psi). The double derivative of the wave function is the same as the energy of the electron.
by Natalie Wang 1B
Sun Oct 20, 2019 4:35 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation
Replies: 3
Views: 66

Re: Shrodinger Equation

Schrodinger's equation is used to describes the probable positions of an electron in an atom. The equation involved sin and cos, so the graph is in waves. This connects to how electrons have wavelike properties.
by Natalie Wang 1B
Sat Oct 12, 2019 8:44 pm
Forum: DeBroglie Equation
Topic: Resonance
Replies: 2
Views: 40

Re: Resonance

I'm not exactly sure what resonance of momentum is. However, (fun fact) there is this process called surface plasmon resonance for metal. Basically, when light hits a metal, like gold, the atoms' electron clouds absorb the light and begin moving around. Then, these electron clouds reflect leftover l...
by Natalie Wang 1B
Sat Oct 12, 2019 8:36 pm
Forum: DeBroglie Equation
Topic: Circular standing waves
Replies: 4
Views: 43

Re: Circular standing waves

The circular standing wave model shows possible wave movements of an electron around the nucleus. The model shows multiple waves to show that electrons oscillate and have wavelike properties.
by Natalie Wang 1B
Sat Oct 12, 2019 8:33 pm
Forum: DeBroglie Equation
Topic: Knowing Which Equation to Use
Replies: 4
Views: 69

Re: Knowing Which Equation to Use

At the moment, I'm distinguishing them based off of electromagnetic radiation and the quantum mechanics of electrons. For example, De Brogile's equation can only be applied to electrons, NOT light.
by Natalie Wang 1B
Sat Oct 12, 2019 8:30 pm
Forum: Properties of Electrons
Topic: wavelike properties of an electron
Replies: 4
Views: 71

Re: wavelike properties of an electron

When waves hit something, they bend. This process if called diffraction. For example, if light is shone through a small slit, the waves bend as they interact with each other through that tiny opening. When electrons pass through a crystal, their movement patterns are similar to the patterns of diffr...
by Natalie Wang 1B
Sat Oct 12, 2019 8:26 pm
Forum: Properties of Light
Topic: Equations We’ve Learned So Far
Replies: 11
Views: 171

Re: Equations We’ve Learned So Far

It's important to distinguish between equations that are relevant to light (EM radiation) and quantum movement of electrons. For light specifically, you should pay attention to: These two equations are applied to light in the theory that light is a wave: c = λv = 3*10^8 (speed of light = wavelength ...
by Natalie Wang 1B
Sat Oct 12, 2019 8:25 pm
Forum: Properties of Light
Topic: Equations We’ve Learned So Far
Replies: 11
Views: 171

Re: Equations We’ve Learned So Far

It's important to distinguish between equations that are relevant to light (EM radiation) and quantum movement of electrons. For light specifically, you should pay attention to: These two equations are applied to light in the theory that light is a wave: c = λv = 3*10^8 (speed of light = wavelength ...
by Natalie Wang 1B
Tue Oct 01, 2019 11:42 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical and Molecular Formulas [ENDORSED]
Replies: 5
Views: 105

Re: Empirical and Molecular Formulas [ENDORSED]

Also, a really handy trick with empirical and molecular formulas, is that if you're looking for the molecular formula of a compound, and you know the compound's molar mass (along with the empirical formula's molar mass), you can divide the compound's molar mass by the empirical formula's molar mass....
by Natalie Wang 1B
Tue Oct 01, 2019 11:33 pm
Forum: Molarity, Solutions, Dilutions
Topic: Post- Assessment Problem 16
Replies: 2
Views: 64

Re: Post- Assessment Problem 16

To find molarity, you have to divide the mols of solute by the volume of the solution. Convert KCL to mols. Then, convert the 125 mL to L. Finally, divide the mols of KCL by the volume in L to get the answer.
by Natalie Wang 1B
Tue Oct 01, 2019 11:30 pm
Forum: Molarity, Solutions, Dilutions
Topic: Solving for Volume G.5 a)
Replies: 8
Views: 202

Re: Solving for Volume G.5 a)

Sodium Carbonate has two sodium ions, so the ratio needs to be taken into account. When the problem asks you to find the volume for 2.15 mM of Na+, you need to convert 2.15 mM of Na+ into the amount of moles for sodium carbonate. To do that, you would need to show how 1 mol of sodium carbonate has 2...
by Natalie Wang 1B
Tue Oct 01, 2019 11:03 pm
Forum: Student Social/Study Group
Topic: Study Group Fall 2019
Replies: 32
Views: 1668

Study Group Fall 2019

I don't know if anyone has done this yet, but I would really like to start a study group! We can reserve study rooms in some of the halls on the hill. Reply if you're interested!
by Natalie Wang 1B
Tue Oct 01, 2019 10:56 pm
Forum: General Science Questions
Topic: Order of Elements When Writing Out a Compound
Replies: 8
Views: 176

Re: Order of Elements When Writing Out a Compound

I actually asked my TA, and he said that for now, we don't need to know how to write chemical formulas correctly. We also don't need to know how to write out chemical formulas from just the compound's name for our first test! Apparently, we'll be learning the basics of chemical formulas and nomencla...

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