Search found 30 matches
- Thu Jun 07, 2018 12:44 am
- Forum: Lewis Acids & Bases
- Topic: Weak vs strong acids [ENDORSED]
- Replies: 7
- Views: 1006
Re: Weak vs strong acids [ENDORSED]
In the textbook it talks about how organic acids are weaker than acetic acids so depending on the compound, you can try to deduce strength based off of chemical formula. The formula for organic acids is COOH, and acetic acids are CH3COOH.
- Thu Jun 07, 2018 12:37 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Chelating complex
- Replies: 7
- Views: 684
Re: Chelating complex
The textbook cites a chelate as a complex with more than 1 ligand forming a ring of atoms with the central metal atom. These must occur with polydentate ligands.
- Thu Jun 07, 2018 12:29 am
- Forum: Bronsted Acids & Bases
- Topic: How to identify a Bronsted acid or base
- Replies: 11
- Views: 4315
Re: How to identify a Bronsted acid or base
How can you tell if it is a Bronsted acid or base without the reaction though? For example, on J1, you are asked to identify if it is a Bronsted acid or base just by the compound. How would you do this? I'm also confused on how to do this. How can we tell whether or not a hydrogen has been donated ...
- Wed May 30, 2018 4:52 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Drawing
- Replies: 7
- Views: 809
Re: VSEPR Drawing
We'll need to know the bond angles, and not necessarily how to draw the geometric shape, but we will need to be able to identify them.
- Wed May 30, 2018 4:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.13 part c
- Replies: 4
- Views: 432
Re: HW 4.13 part c
I don't see any errors in your reasoning and I do think the 2 double bonded oxygens would produce a more favorable molecule. I guess the only good thing is that the whether they're double or single bonds wouldn't affect the shape or bond angles for the problem.
- Wed May 30, 2018 4:35 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 4.3 Homework
- Replies: 3
- Views: 683
Re: 4.3 Homework
HCN is linear because lone pairs only affect shape when they're on the central atom- so only if they were on carbon would we see a different shape. For CH2N2, C is the central atom paired with all 4 atoms, making it tetrahedral.
- Sat May 26, 2018 9:55 am
- Forum: Resonance Structures
- Topic: ranking
- Replies: 11
- Views: 1486
Re: ranking
vivianndo_1L wrote:If the two resonance structures have the same formal charge, would they be considered equal in rank?
I believe so
- Sat May 26, 2018 9:53 am
- Forum: Electronegativity
- Topic: Electronegativity Caluclations
- Replies: 4
- Views: 604
Re: Electronegativity Caluclations
I'm not sure if we'll ever be given them, so it's helpful to just know the trend- that electronegativity increases as you go across a period and decreases as you go down.
- Sat May 26, 2018 9:44 am
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge with ions
- Replies: 4
- Views: 795
Re: Formal charge with ions
You calculate it the same as you would if there were no charge, and should get the overall charge of the ion when adding up the formal charges of each atom.
- Thu May 24, 2018 3:42 pm
- Forum: Dipole Moments
- Topic: Meaning of an induced dipole
- Replies: 3
- Views: 1844
Re: Meaning of an induced dipole
The energy values he gave refer to the energy of the attraction.
- Thu May 24, 2018 3:26 pm
- Forum: Octet Exceptions
- Topic: Confusion on exceptions to the octet rule
- Replies: 2
- Views: 543
Re: Confusion on exceptions to the octet rule
I believe it starts at the beginning of the p group of period 3 with aluminum because silicon can have an expanded octet. In aluminum's case though, while I think it could potentially have an expanded octet, like Boron it can function well with 6 electrons so often has a reduced one.
- Thu May 24, 2018 3:16 pm
- Forum: Dipole Moments
- Topic: Non-polar and dipoles
- Replies: 3
- Views: 436
Re: Non-polar and dipoles
A molecule can have dipole moments and be nonpolar if the polar bonds are symmetrical and the same charge, meaning they could potentially cancel each other out.
- Sat May 19, 2018 3:00 pm
- Forum: Octet Exceptions
- Topic: Expanded Octet Rules
- Replies: 7
- Views: 1083
Re: Expanded Octet Rules
It begins with the non-metals in the third period or below, they are able to do this because they have empty d subshells that can house the extra electrons. Based off of what we learned with quantum numbers and electron shells & subshells, I always thought 3p came before 3d so how is this possi...
- Sat May 19, 2018 2:58 pm
- Forum: Octet Exceptions
- Topic: Exceptions [ENDORSED]
- Replies: 7
- Views: 1284
Re: Exceptions [ENDORSED]
ALSO! remember to look at formal charges! I think this is one of the easiest ways to determine if extra electrons or bonds are needed. If you know the atom includes the d orbital and you follow the octet rule and have electrons left over which lead to a charge, then you can try to determine if you ...
- Sat May 19, 2018 2:50 pm
- Forum: Lewis Structures
- Topic: Test #3
- Replies: 11
- Views: 1349
Re: Test #3
Specifically what hw questions we should know how to do for this test? Based off of what's included on his outline for chapter 3 and since we did electron configurations on the midterm, I would say it'd be useful to do 3.33 and upwards which includes covalent bond problems which have to do with bui...
- Sun May 06, 2018 7:34 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration Exceptions
- Replies: 2
- Views: 410
Re: Electron Configuration Exceptions
Yes, for the midterm I think we only have to know copper and chromium. However, this does show up in some hw problems so the exception where the s shell only has 1 electron is also true for the elements in the column just below Cr and Cu, which are molybdenum and silver. This is for the same reason,...
- Sun May 06, 2018 7:23 pm
- Forum: Trends in The Periodic Table
- Topic: Trends to Know
- Replies: 12
- Views: 1337
Re: Trends to Know
Another trend is electron affinity. Electron affinity tells how how much energy must either be supplied (-) or is released(+) when an electron attaches to an atom. It generally increases as you move right and up along the periodic table. However, noble gases in group 18 have low ones because they're...
- Sun May 06, 2018 7:18 pm
- Forum: Trends in The Periodic Table
- Topic: 2.67 part C (electron affinity)
- Replies: 3
- Views: 455
Re: 2.67 part C (electron affinity)
I was also confused about this problem but electron affinity is discussed in section 2.11 on pages 56-57. Though the general trend is that electron affinities are highest toward the right of the periodic table, figure 2.28 indicates that nitrogen is relatively more stable than carbon. It shows the e...
- Sun Apr 29, 2018 9:23 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: ∆P and ∆X
- Replies: 5
- Views: 663
Re: ∆P and ∆X
Specifically, deltaP is the uncertainty in momentum and deltaX is uncertainty in position of something. These allow us to estimate how big or small our uncertainty about either one of these is. For example, 3 x 10^(5) has a larger uncertainty than 3 x 10^(-29). We can also use Heisenberg's to find t...
- Sun Apr 29, 2018 9:15 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Finding velocity (delta)V [ENDORSED]
- Replies: 2
- Views: 341
Re: Finding velocity (delta)V [ENDORSED]
Also, another way to do these problems as seen in the book's example is to set it up as deltaV= (h/2pi)/(2*m*deltaX) so you combine the two steps
- Sun Apr 29, 2018 9:10 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: In class problem [ENDORSED]
- Replies: 6
- Views: 843
Re: In class problem [ENDORSED]
In this case, because we solved for the uncertainty in velocity we could compare the value to the speed of light because nothing can travel faster than it. I'm not sure what we would compare if we were looking at other things like the reasonability of uncertainty in position.
- Sun Apr 22, 2018 5:14 pm
- Forum: Photoelectric Effect
- Topic: Significance of intensity [ENDORSED]
- Replies: 7
- Views: 752
Re: Significance of intensity [ENDORSED]
Continuing off that note, when light acts as a wave, or for any wave, the intensity relates to the amplitude/height of the wave. Specifically, I think in one part of the textbook it referenced that in terms of the wave model intensity is proportional to the square of amplitude to the wave. It also ...
- Sun Apr 22, 2018 5:11 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Post-Module [ENDORSED]
- Replies: 3
- Views: 352
Re: Photoelectric Post-Module [ENDORSED]
I was also confused about part b for this problem. If we do divide the work function by Avogadro's number as previously suggested, we'd only get one of the answer options if we don't convert 150.6 kJ to 150,600 J, which is something I feel like we'd have to do??
- Sun Apr 22, 2018 4:41 pm
- Forum: Properties of Light
- Topic: test 2
- Replies: 18
- Views: 1602
Re: test 2
QuincyH1G wrote:Is test 2 only on the Quantum World? Will there be anything before that covered?
Yep! It'll just be the quantum world, specifically up to 1.5 in the textbook which covers the wave-particle duality of matter and De Broglie's wave equation.
- Sun Apr 15, 2018 2:57 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: When to use MiVi=MfVf
- Replies: 8
- Views: 4389
Re: When to use MiVi=MfVf
Are there some cases where you'll have to use both the M=n/v and MiVi=MfVf equations in a problem?
- Sun Apr 15, 2018 2:48 pm
- Forum: Photoelectric Effect
- Topic: Intensity VS Energy Models? [ENDORSED]
- Replies: 4
- Views: 534
Re: Intensity VS Energy Models? [ENDORSED]
To add on to this, does light intensity matter for the photoelectric effect?
- Sun Apr 15, 2018 2:00 pm
- Forum: Properties of Light
- Topic: Properties of Light [ENDORSED]
- Replies: 5
- Views: 552
Re: Properties of Light [ENDORSED]
A photon is a particle representing a quantum of light or other electromagnetic radiation. I believe the concept is that light shares characteristics of acting as a wave and as a particle. Photons experience refraction like a wave but it also contains a fixed energy like a particle. I hope this hel...
- Sun Apr 15, 2018 1:55 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical and Molecular Formulas [ENDORSED]
- Replies: 4
- Views: 418
Re: Empirical and Molecular Formulas [ENDORSED]
Yeah this is correct. For the molecular formula because it's the "actual" number of atoms all we had to do was count them and for the empirical formula, because it's the "relative" number of atoms per element, we could use the molecular formula we to find the ratio for the amount...
- Sun Apr 15, 2018 1:50 pm
- Forum: SI Units, Unit Conversions
- Topic: Chemistry Review Section E
- Replies: 4
- Views: 522
Re: Chemistry Review Section E
Yes, in that question when it asks for the amount of ions it essentially means the same thing as finding the mols of Cu2+ ions in the overall CuBr2 compound. For this, you'd divide the given amount of CuBr2 (3 g) by the total molar mass of the compound (in g/mol). Then, because there's 1 mol of Cu2+...
- Sun Apr 15, 2018 1:37 pm
- Forum: SI Units, Unit Conversions
- Topic: Moles mols mol? [ENDORSED]
- Replies: 21
- Views: 9092
Re: Moles mols mol? [ENDORSED]
Naqiyah Qadir 1I wrote:They are all the same but M (molarity) is given in moles/Liter, correct?
Yep! And the hint for when to use that is it often asks for what the "concentration" of the solution is.