Search found 50 matches

by alexfwang3g
Tue Dec 03, 2019 4:31 pm
Forum: Sigma & Pi Bonds
Topic: Unhybridized orbitals.
Replies: 3
Views: 30

Unhybridized orbitals.

Could somebody explain the difference between pi bonds and sigma bonds in addition to how unhybridized orbitals allow pi bonds to form?
by alexfwang3g
Tue Dec 03, 2019 4:29 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: pH, pKa, pKb
Replies: 5
Views: 39

Re: pH, pKa, pKb

pH, pKa, pKb are all calculated through -log[] or hydrogen ions, hydronium ions, and hydroxide ions respectively.
by alexfwang3g
Tue Dec 03, 2019 4:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 9C.5
Replies: 4
Views: 54

Re: 9C.5

Draw the ligand and find out which atoms have lone pairs and then the denticity should be able to be found.
by alexfwang3g
Tue Dec 03, 2019 4:25 pm
Forum: Biological Examples
Topic: Hydrogen Bonding sites
Replies: 8
Views: 48

Re: Hydrogen Bonding sites

Each lone pair on an oxygen, nitrogen, or fluorine is a potential hydrogen bonding site. Also, a hydrogen that is attached to an oxygen, nitrogen, or fluorine is also a potential hydrogen bonding site.
by alexfwang3g
Tue Dec 03, 2019 4:24 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pH for weak Acids
Replies: 3
Views: 22

Re: Calculating pH for weak Acids

As long as you have the concentration, just plug it into the formula. It's pretty rudimentary for 14A.
by alexfwang3g
Wed Nov 27, 2019 12:16 pm
Forum: Dipole Moments
Topic: Hydrogen Bonding Sites
Replies: 9
Views: 58

Re: Hydrogen Bonding Sites

Anywhere where F, O, or N can bond with one another through a Hydrogen atom.
by alexfwang3g
Wed Nov 27, 2019 12:16 pm
Forum: Lewis Acids & Bases
Topic: Identifying Acids and Bases
Replies: 8
Views: 36

Re: Identifying Acids and Bases

Strong bases contain group 1/2 elements. Strong acids should just be memorized. There's only 6 - HCl, H2SO4, HI, HNO3, HBr, HClO4.
by alexfwang3g
Wed Nov 27, 2019 12:14 pm
Forum: Lewis Acids & Bases
Topic: Lewis acid vs regular acid?
Replies: 4
Views: 22

Re: Lewis acid vs regular acid?

They're the same thing - it's just a difference in whether you view them in terms of electrons or protons (h+).
by alexfwang3g
Wed Nov 27, 2019 12:13 pm
Forum: Lewis Acids & Bases
Topic: Acid and Base Strength
Replies: 7
Views: 41

Re: Acid and Base Strength

Strong acids fully dissociate in solution, same with strong acids. As for specific acids, they're usually HCl, H2SO4, HI, HNO3, HBr, HClO4. Strong bases are usually hydroxide paired with cations from the first two groups.
by alexfwang3g
Wed Nov 27, 2019 12:11 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted acid
Replies: 9
Views: 352

Re: Bronsted acid

HBr is a proton giver and a lone pair/electron acceptor.
by alexfwang3g
Thu Nov 21, 2019 10:21 am
Forum: Hybridization
Topic: Quiz 2 Hybridization Question
Replies: 4
Views: 42

Re: Quiz 2 Hybridization Question

No hybridization is on the test.
by alexfwang3g
Thu Nov 21, 2019 10:21 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle of bent
Replies: 17
Views: 88

Re: Bond Angle of bent

Depends on the number of lone pairs. If it's two, then <109.5 and if it's one <120.
by alexfwang3g
Thu Nov 21, 2019 10:20 am
Forum: Hybridization
Topic: for test 2
Replies: 7
Views: 54

Re: for test 2

No, just IMF's and shapes and sigma/pi bonds.
by alexfwang3g
Thu Nov 21, 2019 10:20 am
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bond Sites
Replies: 5
Views: 62

Re: Hydrogen Bond Sites

Fluorine, Oxygen, or Nitrogen with Hydrogen in between two of any of the three elements.
by alexfwang3g
Thu Nov 21, 2019 10:19 am
Forum: Dipole Moments
Topic: Intermolecular Forces
Replies: 7
Views: 56

Re: Intermolecular Forces

Draw it out and identify dipole or lack of dipole. Consider if there is F, O, or N for hydrogen bonding. Every molecule has LDF.
by alexfwang3g
Sun Nov 10, 2019 11:41 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: What is hydrogen bonding?
Replies: 3
Views: 20

What is hydrogen bonding?

A synopsis of the question above in addition to an explanation of why they have to be F, O, or N.
by alexfwang3g
Sun Nov 10, 2019 11:22 am
Forum: Bond Lengths & Energies
Topic: polarizability
Replies: 9
Views: 33

Re: polarizability

The respective sizes of the molecules usually determines the molecule's polarizability - its ability to be polarized. Larger elements such as I usually are easily polarized instead of smaller elements like F. Polarizability doesn't necessarily determine the state of the molecule, but instead it is t...
by alexfwang3g
Wed Oct 30, 2019 11:21 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Will we have to do calculations with the wave functions?
Replies: 1
Views: 25

Will we have to do calculations with the wave functions?

Do we have to know how to do things with the wave function calculations or do we just have to know of them?
by alexfwang3g
Wed Oct 30, 2019 11:19 pm
Forum: Resonance Structures
Topic: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?
Replies: 4
Views: 38

Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

I know that double bonds are shorter than single bonds. But in a resonance structure, they're the same length. Why?
by alexfwang3g
Wed Oct 30, 2019 11:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Why does 3d come before 4s?
Replies: 2
Views: 22

Why does 3d come before 4s?

On the periodic table, 4s comes before 3d so shouldn't it be put before 3d in the electron config?
by alexfwang3g
Wed Oct 30, 2019 11:15 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 25

Re: Drawing Lewis Structures

Put the least electronegative element in the middle and the remaining elements around it. Then, count the total valence electrons and proceed accordingly.
by alexfwang3g
Wed Oct 30, 2019 10:54 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 28
Views: 186

Re: Midterm

Midterm covers up to chemical bonds.
by alexfwang3g
Wed Oct 23, 2019 11:50 pm
Forum: Ionic & Covalent Bonds
Topic: What topic are we on?
Replies: 11
Views: 110

Re: What topic are we on?

Just do quantum questions since the syllabus says to do recently covered material.
by alexfwang3g
Wed Oct 23, 2019 11:50 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: l values
Replies: 4
Views: 53

Re: l values

l values can exceed 3 when the atom is excited.
by alexfwang3g
Wed Oct 23, 2019 11:48 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What's the difference between subshell vs orbitals?
Replies: 8
Views: 65

Re: What's the difference between subshell vs orbitals?

The l value is the subshell. The ml value gives the orbitals.
by alexfwang3g
Wed Oct 23, 2019 11:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: how to do 1.D.23?
Replies: 2
Views: 32

Re: how to do 1.D.23?

Make sure to include the +1/2 and -1/2 for electric spin. Therefore, multiple the answer you would originally get by 2.
by alexfwang3g
Wed Oct 23, 2019 11:42 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Order of electron configuration
Replies: 6
Views: 39

Re: Order of electron configuration

3d comes before 4s due to its lower energy state.
by alexfwang3g
Thu Oct 17, 2019 12:33 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: uncertainty
Replies: 3
Views: 29

Re: uncertainty

Use Heisenberg's indeterminacy equation. Uncertainty of position * Uncertainty of momentum must be greater than Planck's constant divided by 4pi. The closer it is to the constant of h/4pi, the less uncertain it is. However, there is always uncertainty in these equations due to light's momentum.
by alexfwang3g
Thu Oct 17, 2019 12:31 am
Forum: Properties of Light
Topic: How does light have momentum but we assume it has no mass?
Replies: 4
Views: 38

How does light have momentum but we assume it has no mass?

We say light has no mass, therefore it moves at the speed of light. However, it is able to affect small particles such as electrons and can affect them due to its momentum. Since momentum is calculated by m*v, it is naturally contradictory. Can someone explain??
by alexfwang3g
Thu Oct 17, 2019 12:29 am
Forum: Properties of Electrons
Topic: Momentum
Replies: 11
Views: 48

Re: Momentum

Calculatively, momentum is calculated as mass * velocity. It is very different than velocity in terms of units and in terms of concept.
by alexfwang3g
Thu Oct 17, 2019 12:28 am
Forum: Properties of Light
Topic: What are the units of hertz
Replies: 41
Views: 239

Re: What are the units of hertz

Cycles per second. Think of it as things done or cycles completed per second. Therefore, finding the inverse of frequency would give you how many cycles or things were done.
by alexfwang3g
Thu Oct 17, 2019 12:26 am
Forum: Properties of Light
Topic: Speed of light
Replies: 13
Views: 79

Re: Speed of light

All EMR moves at the speed of light. Since the calculations utilized is regarding to a type of light, then naturally we should use 3x10^-8 m/s as well.
by alexfwang3g
Sun Oct 13, 2019 3:36 pm
Forum: Photoelectric Effect
Topic: ejecting electons
Replies: 6
Views: 55

Re: ejecting electons

No, one photon only interacts with one electron. Any excess energy is transformed into kinetic energy for the ejected electron.
by alexfwang3g
Sun Oct 13, 2019 3:34 pm
Forum: Balancing Chemical Reactions
Topic: When are atoms lost or created?
Replies: 14
Views: 219

Re: When are atoms lost or created?

Atoms cannot be lost or created in the grand scheme of things due to the law of conservation of mass. However, they can be transformed but ultimately, there are the same number of total atoms left in the universe.
by alexfwang3g
Sun Oct 13, 2019 3:33 pm
Forum: DeBroglie Equation
Topic: When to use DeBroglie Equation
Replies: 16
Views: 164

Re: When to use DeBroglie Equation

You can use this equation to find the variables for everything but light as light's photons do not have a measurable mass.
by alexfwang3g
Sun Oct 13, 2019 3:31 pm
Forum: Properties of Light
Topic: Photon vs Wave Model
Replies: 5
Views: 31

Re: Photon vs Wave Model

Frequency is the cycles per second whereas intensity is number of photons. Increasing the intensity in the photon model does not assist with freeing bound electrons because no matter how many electrons you fire at the metal, if the strength or frequency is not high enough, no electrons will be eject...
by alexfwang3g
Sun Oct 13, 2019 3:28 pm
Forum: Properties of Electrons
Topic: Mass of Electrons
Replies: 6
Views: 26

Re: Mass of Electrons

They're constant at around 9.11 x 10^-31 kg.
by alexfwang3g
Thu Oct 03, 2019 11:33 am
Forum: Molarity, Solutions, Dilutions
Topic: Empirical and Molecular Formulas
Replies: 13
Views: 138

Re: Empirical and Molecular Formulas

If the total molar mass of the molecular formula coincides with the empirical formula, then the empirical formula is the molecular formula. Otherwise, the empirical formula is just a ratio in the form of the lowest possible whole numbers of a molecule. The molecular formula is the actual molecule an...
by alexfwang3g
Thu Oct 03, 2019 11:30 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Units in Answer
Replies: 18
Views: 188

Re: Units in Answer

Should be specified in the question.
by alexfwang3g
Thu Oct 03, 2019 11:28 am
Forum: Limiting Reactant Calculations
Topic: Homework Week 1
Replies: 18
Views: 207

Re: Homework Week 1

Five questions in total, pick and choose among the assigned ones. Due in lecture tomorrow.
by alexfwang3g
Thu Oct 03, 2019 11:28 am
Forum: SI Units, Unit Conversions
Topic: Sig Fig Mistakes
Replies: 17
Views: 185

Re: Sig Fig Mistakes

For multiplication/division, the result should have the same number of sig figs as the value that has the least number of sig figs which is being multiplied/divided. For example, if you are multiplying a value with two sig figs and a value with three sig figs, then the result should have two sig fig...
by alexfwang3g
Thu Oct 03, 2019 11:21 am
Forum: Properties of Light
Topic: Speed of Light
Replies: 41
Views: 974

Re: Speed of Light

The speed of light is always constant.
by alexfwang3g
Sun Sep 29, 2019 1:36 pm
Forum: SI Units, Unit Conversions
Topic: Question E1, visualization
Replies: 2
Views: 84

Re: Question E1, visualization

Yes, visualize the atoms as next to each other so the diameter would be 288 pm which would be the value you'd use in the dimensional analysis to multiply the number of atoms to find the total distance.
by alexfwang3g
Sun Sep 29, 2019 1:33 pm
Forum: Significant Figures
Topic: Basic sig fig question
Replies: 6
Views: 219

Re: Basic sig fig question

Yes, it is common practice to only apply the sig figs rules for the final answer.
by alexfwang3g
Sun Sep 29, 2019 1:26 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: How was a mole originally determined?
Replies: 3
Views: 55

Re: How was a mole originally determined?

It was determined off of Avagadro's number and the number of atoms in 12 grams of carbon-12.
by alexfwang3g
Sun Sep 29, 2019 1:25 pm
Forum: Significant Figures
Topic: How to do sig figs multiplication?
Replies: 2
Views: 29

Re: How to do sig figs multiplication?

For multiplication, the final product should have the same number of sig figs as the value that is being multiplied with the least number of significant figures. In this case, since 7.1 is the least precise value being multiplied with 2 sig figs, the resulting answer would have 2 sigfigs.
by alexfwang3g
Sun Sep 29, 2019 1:19 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy vs Precision
Replies: 10
Views: 130

Accuracy vs Precision

I know that in everyday language, these two terms can be interchangeable. What is the primary difference between the two terms in chemistry.

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