Search found 40 matches

by simona_krasnegor_1C
Sat Nov 28, 2020 2:46 pm
Forum: Coordinate Covalent Bonds
Topic: Hydrogen bonding
Replies: 12
Views: 60

Re: Hydrogen bonding

I think hydrogen bonding is considered distinct because it is an intermolecular force rather than an intramolecular force. I believe that within the molecule, however, there can be covalent character.
by simona_krasnegor_1C
Sat Nov 28, 2020 2:44 pm
Forum: Dipole Moments
Topic: What are dipole moments
Replies: 9
Views: 54

Re: What are dipole moments

The dipole moment has to do with the polarity of of a molecule and is important in determining bond strength. Like said about the organic chemistry tutor on youtube is a life saver!
by simona_krasnegor_1C
Sat Nov 28, 2020 2:37 pm
Forum: Bond Lengths & Energies
Topic: Higher Melting Point
Replies: 19
Views: 87

Re: Higher Melting Point

Iodine's larger amount of electrons make it a bigger atom. This big size creates a high polarizability, making it harder to melt and therefore have a higher melting point.
by simona_krasnegor_1C
Sat Nov 28, 2020 2:35 pm
Forum: Bond Lengths & Energies
Topic: Ionic Character
Replies: 12
Views: 2977

Re: Ionic Character

Since Br has a higher electronegativity than I, NaBr has higher ionic character due to the electronegativity difference.
by simona_krasnegor_1C
Sat Nov 21, 2020 4:48 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 52

Re: Electron Density

Electron density is essentially the probability of finding an electron, and it can change depending on orbital shape. For example, an s orbital may have a higher electron density than a p orbital.
by simona_krasnegor_1C
Sat Nov 21, 2020 4:47 pm
Forum: Ionic & Covalent Bonds
Topic: Polar Bonds
Replies: 16
Views: 46

Re: Polar Bonds

For this, I tend to look at electronegativity and the presence of lone pairs in the lewis structure. Based off of this, we can see which atom wants electrons more and therefore we can see the sharing is not exactly equal, creating a dipole.
by simona_krasnegor_1C
Sat Nov 21, 2020 4:43 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs. Covalent Compounds
Replies: 7
Views: 37

Re: Ionic vs. Covalent Compounds

I usually go off the fact that ionic compounds involve one metal and one nonmetal, while covalent compounds involve two nonmetals.
by simona_krasnegor_1C
Sat Nov 21, 2020 4:42 pm
Forum: Ionic & Covalent Bonds
Topic: Molecule size and ionic character
Replies: 13
Views: 56

Re: Molecule size and ionic character

The main indicator of ionic character is a large electronegativity difference. That being said, usually we can see as trends on the periodic table that atoms/ions with a larger radius tend to be less electronegative.
by simona_krasnegor_1C
Sat Nov 21, 2020 4:41 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Character
Replies: 14
Views: 46

Re: Covalent Character

The smaller the electronegativity difference, the more covalent character!
by simona_krasnegor_1C
Mon Nov 16, 2020 4:58 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1.25 Textbook Problem
Replies: 1
Views: 37

1.25 Textbook Problem

Hey guys! Does anyone have a good way of explaining this problem from the textbook? Thanks! 1.25 Suppose that in some other universe a rule corresponding to the Pauli exclusion principle reads “as many as two electrons in the same atom may have the same set of four quantum numbers.” Suppose further ...
by simona_krasnegor_1C
Sun Nov 15, 2020 5:09 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: ground-state
Replies: 3
Views: 14

Re: ground-state

Like said above, I think ground-state is often implied!!
by simona_krasnegor_1C
Sun Nov 15, 2020 5:08 pm
Forum: Trends in The Periodic Table
Topic: Textbook questions !F
Replies: 6
Views: 35

Re: Textbook questions !F

I believe the numbers are for context, and the answer should be just the arrangement.
by simona_krasnegor_1C
Sun Nov 15, 2020 5:07 pm
Forum: Trends in The Periodic Table
Topic: Atomic size and trend
Replies: 5
Views: 32

Re: Atomic size and trend

Well in a neutral element the number of protons is equal to the number of electrons. I believe when you go down the table, the size increases faster than across a period since new valence shells are added. What causes large atoms with a high proton count to have large atomic radii is their number o...
by simona_krasnegor_1C
Sun Nov 15, 2020 5:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Exceptions?
Replies: 5
Views: 24

Re: Electron Configuration Exceptions?

The 4s subshell has lower energy so it is occupied first!
by simona_krasnegor_1C
Sun Nov 15, 2020 5:02 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Writing Electron Configurations
Replies: 9
Views: 41

Re: Writing Electron Configurations

In addition to what others are saying, I will add that I have seen both ways done before and believe they are both correct (but I am not sure which one Lavelle prefers).
by simona_krasnegor_1C
Mon Nov 09, 2020 9:28 am
Forum: Octet Exceptions
Topic: expanded octet in d orbital
Replies: 4
Views: 14

Re: expanded octet in d orbital

The d-orbtial has extra space (for 10 electrons), so when an element has this orbital, it is more likely to have an expanded octet.
by simona_krasnegor_1C
Mon Nov 09, 2020 9:26 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: H2O ligand vs hydrate
Replies: 2
Views: 94

Re: H2O ligand vs hydrate

Like the above answer states, there is no difference.
by simona_krasnegor_1C
Mon Nov 09, 2020 9:25 am
Forum: Naming
Topic: type of compound
Replies: 3
Views: 118

Re: type of compound

that is amphoteric metal oxide! this means it is a metal oxide that shows basic as well as acidic behavior.
by simona_krasnegor_1C
Mon Nov 09, 2020 9:23 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Avogadro constant
Replies: 12
Views: 73

Re: Avogadro constant

Avogadro's number is used when the question asks for the number of atoms, molecules, or formula units of a specific substance. It is a useful tool for these conversions.
by simona_krasnegor_1C
Mon Nov 09, 2020 9:22 am
Forum: Significant Figures
Topic: 0's
Replies: 21
Views: 119

Re: 0's

In response to Lillian, "inner-zeros" are indeed counted for sig figs.
by simona_krasnegor_1C
Sun Nov 01, 2020 6:22 pm
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 72
Views: 246

Re: Is c always the speed of light?

As stated before, c is the speed of light always!
by simona_krasnegor_1C
Sun Nov 01, 2020 6:21 pm
Forum: Properties of Light
Topic: Do we need to know the ranges of waves on the electromagnetic spectrum?
Replies: 7
Views: 54

Re: Do we need to know the ranges of waves on the electromagnetic spectrum?

Since it can be hard to memorize all of the boundaries, I tried to mainly memorize the order and a few key wavelengths so that I can use reasoning for problems for now. I feel like this was a good place to start for memorizing and I hope it is helpful!
by simona_krasnegor_1C
Sun Nov 01, 2020 6:20 pm
Forum: Properties of Light
Topic: How to remember what v is in equations
Replies: 46
Views: 138

Re: How to remember what v is in equations

In my head, I just think that the "fancy" v is for frequency because they both start with an f. Hope this helps!
by simona_krasnegor_1C
Sun Nov 01, 2020 6:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm grades
Replies: 19
Views: 172

Re: Midterm grades

Like said above, I suspect it will be sometime in the next week. Good luck!
by simona_krasnegor_1C
Thu Oct 29, 2020 5:01 pm
Forum: Photoelectric Effect
Topic: Post-Module Assessment #28
Replies: 2
Views: 18

Post-Module Assessment #28

The following is a question from the photoelectric effect post-module assessment: 28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. Answer the following three questions. A. What is the kinetic energy of...
by simona_krasnegor_1C
Fri Oct 23, 2020 2:02 pm
Forum: Biological Examples
Topic: Hemoglobin
Replies: 8
Views: 179

Re: Hemoglobin

They are both hemeproteins. Their main physiological value is their ability to bind to oxygen.
by simona_krasnegor_1C
Fri Oct 23, 2020 2:00 pm
Forum: Biological Examples
Topic: Myoglobin
Replies: 4
Views: 212

Re: Myoglobin

Myoglobin is found in muscle cells and binds to oxygen. This binding helps provide extra oxygen, which in turn powers muscular contractions.
by simona_krasnegor_1C
Fri Oct 23, 2020 1:56 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: strengths
Replies: 4
Views: 145

Re: strengths

What Ethan said about the boiling point is a great point. The higher the boiling point, the more energy required to break apart the bonds. The more energy required to break apart the bonds, the stronger those bonds are.
by simona_krasnegor_1C
Fri Oct 23, 2020 1:54 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Viscosity
Replies: 19
Views: 445

Re: Viscosity

For me, when I think of high viscosity I think of things like honey and syrup. The viscosity is like the thickness, and depends on internal frictional force.
by simona_krasnegor_1C
Fri Oct 23, 2020 1:53 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: Hydrogen Bonding and Dipole-Dipole
Replies: 2
Views: 132

Re: Hydrogen Bonding and Dipole-Dipole

I believe hydrogen bonds are a specific type of dipole-dipole interaction. I think the idea of a partial positive region and partial negative region is a commonality that occurs in both bonds.
by simona_krasnegor_1C
Sat Oct 17, 2020 10:42 am
Forum: Trends in The Periodic Table
Topic: Octet Expansion
Replies: 5
Views: 167

Re: Octet Expansion

Adding on the what has been said about period 3 and below, it is important to note that this means period 2 elements, such as C, N, O, and F, cannot expand their octet.
by simona_krasnegor_1C
Sat Oct 17, 2020 10:40 am
Forum: Trends in The Periodic Table
Topic: Nitrogen
Replies: 7
Views: 160

Re: Nitrogen

As stated before, Nitrogen has a half-filled p shell. Since it is half-full, adding another electron would make it unstable. Therefore, something like Carbon has a greater affinity for electrons than Nitrogen.
by simona_krasnegor_1C
Sat Oct 17, 2020 10:38 am
Forum: Trends in The Periodic Table
Topic: Atomic Radii
Replies: 11
Views: 301

Re: Atomic Radii

Something interesting that I read that I thought was worth sharing is that the term atomic radius can refer to an ionic radius, covalent radius, metallic radius, or van Der Waals radius!
by simona_krasnegor_1C
Sat Oct 17, 2020 10:34 am
Forum: Trends in The Periodic Table
Topic: Exceptions to Electronegativity
Replies: 6
Views: 164

Re: Exceptions to Electronegativity

Agreeing with the above posts, noble gases are the only exception. This is because noble gases have a full valence electron shell, so they do not attract more electrons as they don't need them.
by simona_krasnegor_1C
Sat Oct 17, 2020 10:30 am
Forum: Student Social/Study Group
Topic: How are you studying?
Replies: 196
Views: 884

Re: How are you studying?

I completely agree with the two posts above. Studying can often times be subjective so I would try to find the method that works best for you personally. For me, watching the lectures while taking notes and using the modules to review concepts I don't understand helps me, along with doing the saplin...
by simona_krasnegor_1C
Wed Oct 07, 2020 12:15 pm
Forum: Empirical & Molecular Formulas
Topic: Percent comp calculations
Replies: 5
Views: 77

Re: Percent comp calculations

To reiterate what others have posted above, when given the molecular formula your first step is to find the molar mass. Once you have the total more mass, you can find the molar mass of each individual atom and divide that by the total and multiply by 100% to get the mass percent composition!
by simona_krasnegor_1C
Wed Oct 07, 2020 12:11 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 8
Views: 67

Re: Formula Units

To add to what others are saying, I think it's important to point out that Avogadro's number has multiple units, such as atoms, molecules, formula units, etc, making it an extremely useful conversion factor.
by simona_krasnegor_1C
Wed Oct 07, 2020 12:06 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mol VS Mole
Replies: 17
Views: 203

Re: Mol VS Mole

yes they are the same thing! which is a little funny considering that it is only 1 letter shorter and is still an abbreviation.
by simona_krasnegor_1C
Wed Oct 07, 2020 12:04 pm
Forum: Significant Figures
Topic: When are sig figs applied?
Replies: 12
Views: 77

Re: When are sig figs applied?

I agree with what others are saying above; I usually do not take sig figs into consideration until the very end of the problem in order to be as accurate as possible!
by simona_krasnegor_1C
Wed Oct 07, 2020 11:59 am
Forum: Balancing Chemical Reactions
Topic: Fractions
Replies: 26
Views: 140

Re: Fractions

Not sure if anyone mentioned this but I also wanted to add that when you multiply the fraction (and hence multiply all the other reactants and products) the equation is equivalent to what it was previously; as long as you multiply the chemical reaction entirely by the same number, and the ratio is t...

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