Search found 31 matches

by Tina Wen 1G
Tue Jun 12, 2018 7:32 pm
Forum: Bond Lengths & Energies
Topic: Test 3 Final Question (a)
Replies: 3
Views: 174

Re: Test 3 Final Question (a)

Thank you that explains everything perfectly.
by Tina Wen 1G
Mon Jun 11, 2018 8:02 pm
Forum: Bond Lengths & Energies
Topic: Test 3 Final Question (a)
Replies: 3
Views: 174

Test 3 Final Question (a)

I'm not sure if someone has already posted about this, but could someone help me with the final question in Test 3 (a)? I don't get why the double bond in the structure on the left has a shorter bond length compared to the one on the right? How exactly do you know if a specific bond is shorter in on...
by Tina Wen 1G
Mon Jun 11, 2018 7:55 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-Shape
Replies: 6
Views: 218

Re: T-Shape

Generally for T-shape if you disregard the influence of the lone pairs stating that the angles are 90 degrees and 180 degrees is fine. But with real life experiments there might be slight differences according different T-shaped structures.
by Tina Wen 1G
Mon Jun 11, 2018 7:51 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: weak acids
Replies: 4
Views: 239

Re: weak acids

I think we need to distinguish weak acids from strong acids. Just remember the 7 strong acids and the rest are weak acids.
by Tina Wen 1G
Sun Jun 03, 2018 12:00 pm
Forum: Hybridization
Topic: Question 4.45
Replies: 3
Views: 65

Re: Question 4.45

Both C and O have sp2 hybridization. Bond angle is 120 degrees. And sp2 means one sigma bond and two pie bonds.
by Tina Wen 1G
Sun Jun 03, 2018 11:46 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Question 4.29 [ENDORSED]
Replies: 4
Views: 77

Re: Question 4.29 [ENDORSED]

In this case, the two Chlorine atoms and be connected to two adjacent carbon atoms/ skipping one carbon atom/ opposite carbon atoms. Only when connected to opposite carbon atoms of the benzene ring the dipole moment is canceled out. Imagine two people with the same force pulling a string — the force...
by Tina Wen 1G
Sun Jun 03, 2018 11:39 am
Forum: Bond Lengths & Energies
Topic: Test 3 Q 8 [ENDORSED]
Replies: 9
Views: 394

Re: Test 3 Q 8 [ENDORSED]

Yes thinking about resonance structure would help! For SO4 each S-O bond is something between single and double bond, whereas SO3 is solid double bond, which makes it stronger
by Tina Wen 1G
Thu May 24, 2018 9:08 am
Forum: Determining Molecular Shape (VSEPR)
Topic: shape of water
Replies: 8
Views: 189

Re: shape of water

I thought this was the name of a movie haha. But anyways the shape should be bent. The shape is first more determined by the number of bonding pair which is 2 in this case. And then consider the presence of lone pairs which results in repulsion and distortion of the linear structure. A trigonal pyra...
by Tina Wen 1G
Thu May 24, 2018 9:02 am
Forum: Lewis Structures
Topic: 3.45 quick question
Replies: 3
Views: 108

Re: 3.45 quick question

I see the point. But N has one fewer full shell than Cl which contributes to its electronegativity. I think it’s more understandable to say that N has fewer valence electrons and thus more bonding opportunities than Cl without breaking the octet rule. Also NO2 is like pretty common combination.
by Tina Wen 1G
Thu May 24, 2018 8:58 am
Forum: Bond Lengths & Energies
Topic: Shorter bond length always leads to stronger bond?
Replies: 5
Views: 431

Shorter bond length always leads to stronger bond?

Does shorter bond length always leads to stronger bond? Any exceptions?
by Tina Wen 1G
Thu May 17, 2018 12:28 am
Forum: Lewis Structures
Topic: Central atom
Replies: 7
Views: 209

Re: Central atom

Usually the atom with the fewest valence electrons is the central atom. It has more space accept electrons shared with other atoms. Hence carbon goes in the middle since it has 4 valence electrons and can form 4 bonds with surrounding atoms.
by Tina Wen 1G
Thu May 17, 2018 12:18 am
Forum: Ionic & Covalent Bonds
Topic: Formaldehyde Formula
Replies: 2
Views: 99

Re: Formaldehyde Formula

HCHO shows the structure of the molecule while H2CO, or the more commonly used CH2O is the standard molecular formula that does not indicate structure.
by Tina Wen 1G
Thu May 17, 2018 12:15 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Bond Dissociation
Replies: 2
Views: 120

Re: Bond Dissociation

Compared to single bond, triple bond means more electrons are shared, shorter bond length, and stronger connection between the bonding atoms. Therefore, single bond is weaker than triple bond.
by Tina Wen 1G
Sun May 13, 2018 4:15 am
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 5
Views: 183

Re: Resonance Structures

If that is required by the question. If it’s not mentioned then it’s safer to draw all resonance structure.
by Tina Wen 1G
Sun May 13, 2018 4:12 am
Forum: Lewis Structures
Topic: octect rule
Replies: 4
Views: 126

Re: octect rule

We can break the octect rule when the bonding atom has empty d or f orbitals that are available for additional bonding. We should always find the optimized bonding with individual formal charge closest to zero. First try following the octect rule but if involving d or f orbitals would lead to more s...
by Tina Wen 1G
Fri May 11, 2018 2:43 pm
Forum: Lewis Structures
Topic: SO2
Replies: 5
Views: 305

Re: SO2

2 double bonds with 2 oxygen atoms and sulfur in the middle with a lone pair is the most stable structure for SO2. Sulfur has the empty 3d orbital that can participate in bonding so it’s okay for sulfur to carry more than 8 electrons.
by Tina Wen 1G
Sun May 06, 2018 6:55 pm
Forum: Trends in The Periodic Table
Topic: Largest in Atomic Radii?
Replies: 5
Views: 105

Re: Largest in Atomic Radii?

Having more protons mean that the atom/ion has stronger ability to attract electrons towards the center nucleus. Hence the smaller the atomic radii. Hope this helps.
by Tina Wen 1G
Sun May 06, 2018 6:49 pm
Forum: Ionic & Covalent Bonds
Topic: Help on 2.43
Replies: 3
Views: 118

Re: Help on 2.43

IMG_9120.jpg
answer
by Tina Wen 1G
Sun May 06, 2018 6:32 pm
Forum: Lewis Structures
Topic: Help on 3.35
Replies: 2
Views: 81

Re: Help on 3.35

IMG_9119.jpg
answer
by Tina Wen 1G
Fri Apr 27, 2018 3:52 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Test 2 Q4 help [ENDORSED]
Replies: 3
Views: 194

Test 2 Q4 help [ENDORSED]

How should we solve the difference in energy for Q4 in Test 2? And what is the final answer? Thank you
by Tina Wen 1G
Fri Apr 27, 2018 3:48 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How detailed should the configurations be?
Replies: 3
Views: 115

How detailed should the configurations be?

Hi, how detailed should the electron configurations be? Can we always apply shorthand parentheses like [Ar] 3s^2? For p sublevels do we need to notify the x, y and z orbitals when writing the configurations (eg. 2px^2 2py^1 2pz^1)?
by Tina Wen 1G
Fri Apr 27, 2018 2:39 pm
Forum: Photoelectric Effect
Topic: Test 2 final question [ENDORSED]
Replies: 15
Views: 482

Test 2 final question [ENDORSED]

For the final question in test 2, how many electrons can 1 thousand photons of UV region send to higher energy levels? What is the quantitative relationship of energy transfer from photons to electrons?
by Tina Wen 1G
Sat Apr 21, 2018 4:06 pm
Forum: DeBroglie Equation
Topic: equations that apply to light only/everything else but light
Replies: 8
Views: 272

equations that apply to light only/everything else but light

During Friday class the professor mentioned E=hv only applies to light and lambda=h/p applies to everything else with mass but light? I wonder why is that?
by Tina Wen 1G
Sat Apr 21, 2018 4:00 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Quiz 2 [ENDORSED]
Replies: 4
Views: 125

Re: Quiz 2 [ENDORSED]

So we won't be tested on the original equation that explains the concept?
by Tina Wen 1G
Sat Apr 21, 2018 3:57 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]
Replies: 2
Views: 77

Re: Confusion with the conclusion sentence of 1.15 in the solutions manual [ENDORSED]

Hi I think the solution manual is not being precise here. During emission the H-atom should move from higher energy levels to lower ones. So technically it should be a transition from n2=3 to n1=1. Also n1 < n2 because that makes their squared reciprocals 1/n1^2 > 1/n2^2. Correct me if I'm wrong.
by Tina Wen 1G
Fri Apr 13, 2018 7:59 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Solving 1.11 [ENDORSED]
Replies: 3
Views: 134

Solving 1.11 [ENDORSED]

1.11 In the spectrum of atomic hydrogen, several lines are generally classi ed together as belonging to a series (for example, Balmer series, Lyman series, Paschen series), as shown in Figs. 1.10 and 2.1. What is common to the lines within a series that makes grouping them together logical? What wou...
by Tina Wen 1G
Fri Apr 13, 2018 7:53 pm
Forum: Properties of Electrons
Topic: History of experiments on the model of atom
Replies: 7
Views: 304

History of experiments on the model of atom

Do we need to know the basic mechanisms and process of the historical experiments on the nature of atoms? Like how the scientists determined the nuclear model of the atom including protons, electrons, neutrons, etc?
by Tina Wen 1G
Fri Apr 13, 2018 7:27 pm
Forum: Properties of Light
Topic: Data to memorize for this chapter [ENDORSED]
Replies: 2
Views: 112

Data to memorize for this chapter [ENDORSED]

Hey I'm wondering what are the key figures and formulas to memorise for this chapter? Like do we need to know the range of frequency and wavelength for different radiation type (eg. x-ray, microwave, visible light)? Or the range of Balmer and Lyman series?
by Tina Wen 1G
Fri Apr 06, 2018 3:22 pm
Forum: Empirical & Molecular Formulas
Topic: F.25
Replies: 2
Views: 93

F.25

For F.25 (b), do we write (CH2)2(NH2)2 or H2N(CH2)2NH2 for molecular formula?
by Tina Wen 1G
Fri Apr 06, 2018 2:47 pm
Forum: SI Units, Unit Conversions
Topic: Conversion rates [ENDORSED]
Replies: 3
Views: 104

Re: Conversion rates [ENDORSED]

https://www.unc.edu/~rowlett/units/sipm.html
In all there are seven SI base units:
the meter for distance,
the kilogram for mass,
the second for time,
the ampere for electric current,
the kelvin for temperature,
the mole for amount of substance, and.
the candela for intensity of light.
by Tina Wen 1G
Fri Apr 06, 2018 2:42 pm
Forum: SI Units, Unit Conversions
Topic: What is the notation for molar mass?
Replies: 15
Views: 538

What is the notation for molar mass?

We know that the notation for mass is m, molar quantity is n. What is the notation for molar mass?

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