Search found 36 matches

by Sally Qiu 4l
Sat Nov 16, 2019 4:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or Angular
Replies: 13
Views: 50

Re: Bent or Angular

i don't believe there's a difference? the textbook may say angular but lavelle referred to it as "bent"
by Sally Qiu 4l
Sat Nov 16, 2019 4:22 pm
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 9
Views: 20

Re: Dissociation Energy

dissociation energy is the energy required to break a bond, and since breaking bonds requires energy, the dissociation energy will be positive
by Sally Qiu 4l
Sat Nov 16, 2019 4:17 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: Boiling Points
Replies: 5
Views: 16

Re: Boiling Points

the stronger the intermolecular force, the higher the boiling point. for example, the boiling point of water is 100 C, while the boiling point of methane (CH4) is like -260 C. water molecules are polar, which means there will be dipole-dipole forces as well as LDF (LDF are present in all molecules i...
by Sally Qiu 4l
Sat Nov 16, 2019 3:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar vs nonpolar
Replies: 6
Views: 24

Re: polar vs nonpolar

i prefer to draw the lewis structure; then you can see if the structure is symmetrical or not.
by Sally Qiu 4l
Fri Nov 08, 2019 7:29 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 5
Views: 47

Re: Dipole Moments

dipole moments are the result of differences in electronegativity, and the atoms share electrons unequally. this creates a partial charge of +/-.
by Sally Qiu 4l
Fri Nov 08, 2019 7:27 pm
Forum: Electronegativity
Topic: memorizing tables
Replies: 9
Views: 39

Re: memorizing tables

i don't think you need to memorize the actual numbers, but you can at least have a general, relative estimate of the values maybe
by Sally Qiu 4l
Fri Nov 08, 2019 7:26 pm
Forum: Dipole Moments
Topic: Dipole - Dipole vs. Hydrogen Bonding
Replies: 7
Views: 156

Re: Dipole - Dipole vs. Hydrogen Bonding

h bonding is an intermolecular force, so attraction between molecules. it is the stronger than dipole-dipole, which is also an intermolecular force. h bonding is weaker than covalent or ionic bonds though.
by Sally Qiu 4l
Fri Nov 08, 2019 7:22 pm
Forum: Lewis Structures
Topic: Formal Charges
Replies: 15
Views: 47

Re: Formal Charges

the charge isn't necessarily for the central atom. the most electronegative atom should have the negative charge
by Sally Qiu 4l
Sun Nov 03, 2019 4:23 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizing power
Replies: 3
Views: 10

Re: polarizing power

ions with high polarizing power cause large distortions in another atom's electron cloud. to determine polarizing power, you'll have to take into consideration the atomic radius and charge; small cations that are highly charged have the most polarizing power. due to the small size, the nucleus of th...
by Sally Qiu 4l
Sun Nov 03, 2019 4:13 pm
Forum: Bond Lengths & Energies
Topic: Resonance bond length
Replies: 4
Views: 14

Re: Resonance bond length

kind of yeah? i see it more as resonance describing the delocalization of electrons. but yes the bond length is the average
by Sally Qiu 4l
Sun Nov 03, 2019 2:49 pm
Forum: Octet Exceptions
Topic: What are radicals
Replies: 7
Views: 26

Re: What are radicals

radicals are compounds that have a lone electron. this makes them very reactive, and they're significant because they can damage DNA and cause mutations.
by Sally Qiu 4l
Sun Nov 03, 2019 2:45 pm
Forum: Dipole Moments
Topic: Dipole moments
Replies: 5
Views: 23

Re: Dipole moments

a dipole moment occurs when atoms in a molecule share electrons unequally. this means there's a difference in electronegativity, and this creates partially negative and positive regions which gives the molecule ionic character
by Sally Qiu 4l
Sun Nov 03, 2019 2:28 pm
Forum: Dipole Moments
Topic: Hydrogen Bond
Replies: 7
Views: 32

Re: Hydrogen Bond

a hydrogen bond is a type of dipole-dipole interaction, but it's specifically between hydrogen and N, O, or F. it's the stronger than dipole-dipole because of the partially positive hydrogen atom and partially negative N O or F
by Sally Qiu 4l
Sun Oct 27, 2019 9:18 am
Forum: Lewis Structures
Topic: Drawing Lewis Structure
Replies: 6
Views: 24

Re: Drawing Lewis Structure

i would assume we have to draw the lone pairs since we haven't been told otherwise. just draw them to be safe
by Sally Qiu 4l
Sat Oct 26, 2019 10:30 pm
Forum: Quantum Numbers and The H-Atom
Topic: Ms and ML
Replies: 6
Views: 28

Re: Ms and ML

ml is actually the quantum number that is from -l to +l. it means that ml can take on integer values from -l to +l; for example, if l was 2, then ml can be -2, -1, 0, 1, or 2. and ms is either -1/2 or +1/2
by Sally Qiu 4l
Sat Oct 26, 2019 2:48 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity vs Electron Affinity
Replies: 6
Views: 31

Re: Electronegativity vs Electron Affinity

electronegativity is how well an atom can attract electrons, or basically an atom's ability to attract electrons. electron affinity is the amount of energy released when an electron is added to a neutral and gaseous atom
by Sally Qiu 4l
Sat Oct 26, 2019 10:08 am
Forum: Trends in The Periodic Table
Topic: atomic radius
Replies: 3
Views: 15

Re: atomic radius

atomic radius is the distance from the nucleus to the outmost shell. i don't think we need to calculate it; i would assume the atomic radius would be either given to us in a problem, or we can solve for it with basic math (correct me if i'm wrong though).
by Sally Qiu 4l
Sat Oct 26, 2019 8:59 am
Forum: Resonance Structures
Topic: Bond Lengths
Replies: 5
Views: 218

Re: Bond Lengths

the electrons in resonance structures are delocalized, and this spreads multiple-bond character over the whole molecule. the resonance structures don't depict how the molecule actually looks like, so the bond lengths are the average between the single and double bonds
by Sally Qiu 4l
Sat Oct 26, 2019 8:54 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: ml alue (i.e., ...-1,0,1,....)
Replies: 2
Views: 17

Re: ml alue (i.e., ...-1,0,1,....)

the l value is determined by the n value, and ml is determined by l. ml can be any whole number from -l to +l; for example, if l=1, then ml can be -1, 0, and +1
by Sally Qiu 4l
Sat Oct 19, 2019 9:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Inner e- and Outer e-
Replies: 14
Views: 68

Re: Inner e- and Outer e-

the inner electrons "shield" the outer electrons from the electrostatic pull of the nucleus. this reduced electrostatic attraction is the "effective nuclear charge". this becomes important later when it comes to ionization and bonding
by Sally Qiu 4l
Sat Oct 19, 2019 12:04 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals vs. Shells
Replies: 5
Views: 31

Re: Orbitals vs. Shells

a shell is the energy level, which is n. orbitals are denoted by ml, and are the shapes that can hold up to 2 electrons. i'll attempt to give an example: n=2, l=1, so we have 2p. there can be 3 values for ml, so we have px, py, and pz. if you remember high school chemistry and electron configuration...
by Sally Qiu 4l
Sat Oct 19, 2019 11:57 am
Forum: *Shrodinger Equation
Topic: Concepts of Schrodinger equation
Replies: 3
Views: 20

Re: Concepts of Schrodinger equation

schrodinger's equation solves for a wave function (treating electrons as matter waves) and it can be used to find the relative location of an electron and the probability of finding an electrons in a location.
by Sally Qiu 4l
Thu Oct 17, 2019 4:57 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 7
Views: 46

Re: Nodal Planes

nodal planes are where the probability of finding electrons is zero. they're derived from schrodinger's equation
by Sally Qiu 4l
Thu Oct 17, 2019 4:47 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty application
Replies: 3
Views: 32

Re: Uncertainty application

in order to use the uncertainty equation, you need to have some value for mass. because photons have no mass, you cannot use the momentum equation p=mv and thus, you cannot calculate the uncertainty
by Sally Qiu 4l
Sat Oct 12, 2019 7:46 pm
Forum: Properties of Electrons
Topic: Electron Excitation
Replies: 6
Views: 25

Re: Electron Excitation

when an electron is excited, it means that it has absorbed energy and has jumped to a higher energy level.
by Sally Qiu 4l
Sat Oct 12, 2019 7:38 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 41
Views: 769

Re: Speed of Light

the speed of light changes depending on the medium it is traveling through; however, the constant 3.00x10^8 m/s is used when assuming the light is traveling through a vacuum. therefore, in our case, the speed of light is constant.
by Sally Qiu 4l
Fri Oct 11, 2019 9:43 am
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Reactions
Replies: 20
Views: 135

Re: Balancing Chemical Reactions

i try to balance the coefficient one by one by making a list, but when i get an odd number, I double the coefficients and that usually works out in the end
by Sally Qiu 4l
Fri Oct 11, 2019 9:41 am
Forum: Properties of Light
Topic: Speed of light
Replies: 9
Views: 48

Re: Speed of light

we use the constant c when we are assuming the situation is in a vacuum. however, it is true that light travels different under different mediums.
by Sally Qiu 4l
Fri Oct 11, 2019 9:37 am
Forum: Properties of Light
Topic: Converting units
Replies: 8
Views: 33

Re: Converting units

To convert from nanometers to angstroms, you multiply by 10.
by Sally Qiu 4l
Thu Oct 03, 2019 2:41 pm
Forum: SI Units, Unit Conversions
Topic: Sig Fig Mistakes
Replies: 17
Views: 126

Re: Sig Fig Mistakes

Letty Liu 1K wrote:Should we round off the numbers as we calculate or leave them as is until the final answer?
I was taught to not round as you calculate, as that would interfere with the accuracy of your final answer. Then, you can round and use the sig figs.
by Sally Qiu 4l
Thu Oct 03, 2019 10:17 am
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula Purpose
Replies: 13
Views: 102

Re: Empirical Formula Purpose

The empirical formula just shows the ratio between the atoms of a compound, and aids in finding the molecular formula.
by Sally Qiu 4l
Thu Oct 03, 2019 10:16 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook Question E15
Replies: 3
Views: 28

Re: Textbook Question E15

The (OH)2 is the hydroxide. The sulfide of the metal is going to have sulfur in the formula. I believe the problem wants you to find the mystery metal M, then find the formula of the sulfide of the metal.
by Sally Qiu 4l
Wed Oct 02, 2019 4:28 pm
Forum: Significant Figures
Topic: Quick General Question!
Replies: 5
Views: 61

Re: Quick General Question!

You've got me questioning my own knowledge on sig figs now, but I was taught that rounding was appropriate when doing sig figs. So 4.70 would be correct.
by Sally Qiu 4l
Wed Oct 02, 2019 4:24 pm
Forum: Empirical & Molecular Formulas
Topic: HW problem F9
Replies: 8
Views: 55

Re: HW problem F9

I'm not sure what you quite mean by the atoms "canceling out", but I would assume atom ratio refers to the subscript on the elements in the formula. More specifically the empirical formula.

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