CHEMISTRY COMMUNITY

Madisen Brown -1C

To determine the stronger acid or base I usually refer to the list of strong acids and bases from the sapling website and base my order on that list. Here's the link for the list if needed. I've found it to be very resourceful: https://sites.google.com/site/chempendi ... cids-bases

Madisen Brown -1C

CH3COOH has a carboxyl group therefore it's considered a weak acid because it dissociates partially to release hydrogen ions.

Madisen Brown -1C

Water can act as both an acid or a base

Madisen Brown -1C

Courtney Situ 3D wrote:Hi there!

NH3 is a weak base since it can donate electrons or accept protons from the nitrogen lone pairs. However, NaCl is not an acid or a base; it's a salt. I think you'd have to put it in the other category.

Hope that helps! :))

Yes, this helped! Thank you so much

Madisen Brown -1C

I seem to be having difficulty identifying the "weak bases" and "other" categories for this problem. I thought that NH3 and NaCl would be weak bases but I've attempted this solution so many times and I seem to not be understanding something. If someone could help me out that'd be...

Madisen Brown -1C

I agree with what Serena mentioned, I believe it's important to know the bond angles from the VSPER model to apply it to other shapes without knowing the exact degree of the angle. More so, if it's greater than or less than, for instance, 109.5

Madisen Brown -1C

I would say the identification of the acids and base (Lewis, Bronsted-Lowry, Arrhenius) and also keeping in mind important chracteristics

Madisen Brown -1C

Resonance structures form a more stable structure due to delocalization.

Madisen Brown -1C

The oxidation number is the total number of electrons an atom gains or loses to form a chemical bond.

Madisen Brown -1C

The structures with the lowest formal charge are the most stable

Madisen Brown -1C

Yes, regions of electron density refer to both lone pairs and bonds.

Madisen Brown -1C

Though one of the oxygens is double-bonded to phosphorus, this only constitutes as one region of electron density

Madisen Brown -1C

Delocalization means the electrons are shared equally through the molecule. For bonds, electrons are typically shared just between the two atoms in the bond. When electrons are delocalized, then they are shared equally throughout and is not shared with just two atoms. Since these electrons are delo...

Madisen Brown -1C

The bonds of both molecules are polar because their electronegativities are different. For BeCl2, the shape of the molecule is linear because there are no lone pairs on the central atom that would cause the molecule to bend or be angular. In a linear shape, the dipoles cancel each other out therefor...

Madisen Brown -1C

During Lavelle's lecture today when he was discussing the hybridization of benzene I noticed him refer to some of the electrons, as well as the sigma and pie bonds of benzene, as being delocalized so I was wondering what he meant by "delocalized" in this context.

Madisen Brown -1C

Yes. X represents the bond atom and E represents the lone pair around the central atom.

Madisen Brown -1C

I usually take formal charge into consideration when determining whether a single, double, or triple bond would yield the most stable structure.

Madisen Brown -1C

Lone pair electrons are included in the region of electron density.

Madisen Brown -1C

Yep! The shape is known as bent or angular because 2 of the 4 bonding sites are lone pairs and the lone pairs force the bonding electrons closer which decreases the bond angle.

Madisen Brown -1C

How do you determine whether there can be lone pairs on the central atom when given the shape? For instance, in this question, they give a trigonal planar structure and a linear structure.

Madisen Brown -1C

The structure should have a doubled bond between C and O (C being the central atom), two lone pairs on O, and two single H bonds. It could be coming up as wrong if you're missing the double bond. Hope this helps!

Madisen Brown -1C

Carbon has a charge of -2!

Madisen Brown -1C

I agree with the other responses! The octet rule should be the primary concern before a formal charge.

Madisen Brown -1C

Elements in row 3 or higher can have expanded octets because they can make use of the d-orbitals. Hope this helps!

Madisen Brown -1C

Hydrogen bonds only with the three most electronegative atoms: N, O, and F. Therefore, O must be on either side to form an H-bond. Hope this helps!

Madisen Brown -1C

Because double bonds have a higher number of electrons, the electrons are pulled in tighter thus the bond length is shorter

Madisen Brown -1C

From my understanding, there's no definitive way to calculate the spin up or spin down. I think it's mainly important to know that no element has the same 4 quantum numbers.

Madisen Brown -1C

Lewis acids are ones that accept an electron. Lewis bases on the other hand donate electrons. Hope this helps!

Madisen Brown -1C

The positive and negative symbols represent the charge of the molecule. Hope this helps!

Madisen Brown -1C

Thanks for organizing this!

Madisen Brown -1C

I ain't never seen two identical fermion particles in the same quantum state. It's always one of them gotta have different quantum numbers.

Madisen Brown -1C

Andrew Jubintoro 3B wrote: $\nu = R(\frac{1}{{n_1}^2}-\frac{1}{{n_2}^2})$
here n₁ is the lower energy level and n₂ is the higher energy level.
n₁ = 1
n₂ = 4
I think you might have switched the two.

I think that is what happened thanks for the help!

Madisen Brown -1C

Uyenvy Nguyen 3C wrote:Did you get a negative value for your frequency? For the frequency, I got positive 3.08*10^15, and I plugged it into the equation wavelength=c/frequency and got 9.73*10^-8 meters. This would be in the UV region.

I believe so, but that makes sense. I think I might've miscalculated somewhere.

Madisen Brown -1C

Andrew Jubintoro 3B wrote:1 meter = 1,650,763.73 wavelengths
Therefore, 1/1,650,763.73 meter = 1 wavelength
1 wavelength = 6.058 x 10^-7 m = 605.8 nm
So it's in the visible light region.
E = hc/ $\lambda$ = 3.28 x 10^-19 J

Thanks for the help!

Madisen Brown -1C

The question reads: In the hydrogen atomic spectrum, what is the wavelength of light associated with the n = 4 to n = 1 electron transition? What part of the electromagnetic spectrum is this wavelength? When I used Rydberg's equation, I got the answer to be -9.73E-8 but the answer is incorrect. Coul...

Madisen Brown -1C

The question reads: The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radiation? To what region of the electromagnetic spectrum does this wavelength correspond (i.e. infrared, ultravio...

Madisen Brown -1C

Hi! The speed of light equations are used when you want to find the wavelength/frequency of a photon, so you can't use it for other objects. You can instead use DeBroglie's equation to find the wavelength! Also, sometimes the question asks if an object's wavelength is detectable/not detectable, whi...

Madisen Brown -1C

When you are finding the wavelength of something that has mass is when you should be using de Broglie, like an electron or an object. Therefore, you cannot use this to calculate the wavelength of photons because they have no mass and must use the other equation to find the wavelength of light. That...

Madisen Brown -1C

I'm having difficulty comprehending when to use De Broglie's equation to find the wavelength and when to use the speed of light equation to find the wavelength. Are there certain conditions for the different equations that I should be aware of? Or any given information/keywords used in a problem tha...

Madisen Brown -1C

Quinton Sprague 2D wrote:I was wondering the same thing. If you check out the post titled "Midterm Nomenclature" it appears to be answered by a TA who says that we will not be expected to know/balance formulas like nitric acid, phosphoric acid, or other compounds as such.

That's a relief! Thank you

Madisen Brown -1C

Is anyone aware if, for MT1, we need to know more complex chemical compounds like sulfite, nitrate, chromate, etc., aside from the basic chemical compounds like water or oxide in the case that we need to write the chemical equation and balance it?

Madisen Brown -1C

could someone explain why d is wrong? i understand why c is correct but i thought the radiation of a wave was related to frequency because radiation/intensity was equal to the square of wavelength which is related to frequency? if this isnt true, what is the radiation of a wave proportional to? D i...

Madisen Brown -1C

In question 3 of focus topic IA, I understand why options A,B, and D are wrong. However, I do not understand why C is correct. I am confused about how the extent of change in the electrical field relates to EM radiation. What is the "extent of change" referring to in the question? The wor...

Madisen Brown -1C

Are we going to have to memorize the difference between the Lyman and Balmer series? I think it's important to remember that Balmer represents the visible light region (n=2) and that Lyman represents the ultraviolet region (n=1). Without this information, it'd be difficult to solve for n1 and n2 wh...

Madisen Brown -1C

I don't think it's necessary if it doesn't specify converting the final answer in nm. However, the wavelength is usually referred to in nm so it might be of benefit to get in the habit of doing the conversion.

Madisen Brown -1C

In question 3 of focus topic IA, I understand why options A,B, and D are wrong. However, I do not understand why C is correct. I am confused about how the extent of change in the electrical field relates to EM radiation. What is the "extent of change" referring to in the question? The wor...

Madisen Brown -1C

Hello! You can use the energy per photon equation (E=hv) and c=(lambda)v to determine the relationship. If you were to rearrange the speed of light equation, you would get v=c/(lambda). You can substitute this into the energy per photon equation so E=hc/(lambda). This may help you visualize the rel...

Madisen Brown -1C

So, I understand that wavelength and frequency are inversely related, and because a higher frequency usually indicates the particle has more energy, is it accurate to say the relationship between wavelength and energy are also inversely related?

Madisen Brown -1C

As you move down the Electromagnetic Spectrum, from red (700nm) to violet (400 nm), the wavelength decreases. Inversely, as the wavelength of a particle decreases, the frequency of that particle increases. So, in context, the color red has a lower frequency than violet. Hope this establishes a bette...

Madisen Brown -1C

I have gotten a 1:1 ratio and converted the product to grams to find the theoretical yield, but I am unsure of what to do after this After converting the limiting reactant to the product in grams, you'll then want to solve for the percent yield by dividing the actual yield (given in the problem) by...

Madisen Brown -1C

Alara Aygen 2E wrote:Hi,
Sometimes some of the coefficients may be missing. So even though you see one stoichiometric coefficient, the rest of the equation may be unbalanced. It is always good to check before solving the question.

Thanks for clarifying! I'll be sure to double-check before proceeding with the problem

Madisen Brown -1C

Oxygen gas is O2 in this case. When elements are in their natural state some of them appear in doubles. You know its a double in this case because you're told its oxygen gas.These elements that naturally appear as doubles are labelled as diatomic molecules. I think they're hydrogen, nitrogen, oxyge...

Madisen Brown -1C

The problem reads, "The psychoactive drug methamphetamine (“speed”), which is sold as the prescription medication Desoxyn, C10H15N, undergoes a series of reactions in the body; the net result of these reactions is the oxidation of solid methamphetamine by oxygen gas to produce carbon dioxide ga...

Madisen Brown -1C

Can we assume that a problem with the stoichiometric coefficients already given in the chemical equation is balanced? In other words, would there ever be a scenario where the stoichiometric coefficients are given, but the equation isn't balanced?

Search found 54 matches