CHEMISTRY COMMUNITY

octaviahuang1f

I think a way to tell weak acids from strong acids is by the bond strength. If the bond is weaker, it would be easier for the acid to donate the H + . The bond would also be easier to break if the resulting anion is stabler. You can also identify a weak acid if it's in the carboxyl group (Edit: orga...

octaviahuang1f

Basically, when a base accepts a proton (H + ) it forms a conjugate acid, and when an acid donates a proton (H + ) it forms a conjugate base. So to write a conjugate acid you add an H+ to the base, and to write a conjugate base you remove an H+ from the acid. e.g. The conjugate acid of O 2- is OH - ...

octaviahuang1f

Like what Isabelle said, a lone pair forms a region of e- density that repels more than bonded pairs. To achieve the least amount of repulsion, the rest of the bond angles become slightly smaller. Hope this helps!!

octaviahuang1f

Additionally, part of the question was a comparison of two double bonds, each with two lone pairs. In this scenario, how would you discover which of the two bond lengths was longer? * Also, is it correct in thinking the lone pairs stretch out the bond length? It basically still depends on the bond ...

octaviahuang1f

I think it also indicates the electron distribution within a molecule. :)

octaviahuang1f

Lone pairs have greater repulsion than bonded pairs. To form a shape with least repulsion between atoms, the bond angles might become smaller when there's a lone pair than if it's bonded. Example: SF4 forms a seesaw shape. XeF4 has two lone pairs on Xe, so to form the shape with least repulsion, it ...

octaviahuang1f

I don't think they are automatically bond together, and it really depends on the formal charge and the octet rule. I'll attach some examples where they don't bond. Hope this helps!!

octaviahuang1f

I think it's determined by the lowest formal charge and not exceeding an octet that's not expanded.

octaviahuang1f

Basically, polarizing power is the ability of the cation to distort the anion. It depends on the size of the cation: the smaller the cation, the closer its traction is to the anion. Polarizing power also increases when the cation is more positively charged. High polarizing power results in ionic bon...

octaviahuang1f

I don't think this was really covered in class, but for H2C(NH2)COOH, it has a carboxylic acid (R-COOH) and an amidogen (NH2-). That leaves the central atom with lowest ionization energy, which is carbon. The carbon goes in the middle, and NH2- and R-COOH go on both sides. Finally the two hydrogen g...

octaviahuang1f

I'm not really sure about this, but it's probably that formaldehyde contains an aldehyde (R-CHO)? Hope this helps!:)

octaviahuang1f

In the silver halides example, increasing size of the anion leads to increasing covalent character of the silver halide (AgF, AgCl, AgBr, Agl).
Increasing size of anion -> more distorted anion -> less solutability.
Hope this helps!!

octaviahuang1f

Yes, I agree that the lone pairs are the dots surrounding that letter. If you subtract the valence electron by these lone pairs and 1/2 the bonding electrons, you get the formal charge. Hope this helps!

octaviahuang1f

I think it's okay to turn in any of the problems covered so far and you haven't done yet since they are all covered by midterm. However, it might depend on your TA. Hope this helps!

octaviahuang1f

Resonance is indicated by double-headed arrows that connect different possible Lewis diagrams for one actual structure. The arrows compare and contrast those possible Lewis structures for a molecule. e.g., the actual structures of N-O in NO3 have a partial double bond character, but on the diagram, ...

octaviahuang1f

Yes, l is the orbital angular momentum number. In this case, you need to match s,p,d,f orbitals with their corresponding angular momentum number (l). Hope this helps!

octaviahuang1f

Hi, I believe what the series describe are Principle quantum numbers(n), or shells as it's usually called. Shells determine the energy levels. Angular momentum quantum number(l) describes the orbital/shape of the subshells (I=0,1,2,3 corresponding to s,p,d,f), and each shell can contain several subs...

octaviahuang1f

In addition to Sara's answer and pls correct me if I'm wrong:), since it's one atom of neon, the molar mass has to be converted using Avogadro's constant.

octaviahuang1f

playground duty :)

octaviahuang1f

I believe the answer is D. From Dr. Lavelle's lecture last week, diffraction pattern is a combination of destructive and constructive waves that leads to specific patterns based on what is causing the diffraction. Constructive interference is "in phase", meaning the waves' peaks and trough...

octaviahuang1f

I believe the list of problems Dr. Lavelle sent us is only for review purposes; you can still choose from any problems covered in class so far within the outline files.

octaviahuang1f

I don't think we need to record it somewhere else, just make sure to post at least three per week haha.

octaviahuang1f

It was too short and I didn't manage to finish it, and most people I heard from didn't finish it as well. I think it might be supposed to be challenging with timing, but I sure need some more practice with timing to be honest.

octaviahuang1f

I believe what Dr Lavelle said was the wavelength needs to be no less than 10^-18 to be measurable.

octaviahuang1f

Yes, it can be used to convert from moles to molecules as well (1 mole= 6.022 × 10^23 molecules). I think it depends on the basic units of the substance; whether it's atoms or molecules.

octaviahuang1f

Since this question is about the mass of KNO3 and H20 in the solution, I don't think we need to convert them to volumes. I believe "Describe how you would prepare the solution" refers to the actual steps it takes to prepare this solution in a laboratory. :)

octaviahuang1f

Hi Maria, I believe t is ton, a non-SI unit that roughly equals to 1000 kilograms. I'm unsure about what will be on the test though.. anyway hope this helps! :)

octaviahuang1f

In today's lecture we learned that Celsius is often used for measurements, and Kelvin is often used in calculation. One of the reasons is probably that Celsius and Kelvin have the same size of scale (K=C+273.15), making it easier to convert one of them to the other. :)

octaviahuang1f

I remembered from class that it's better to aim for 3 digits after the decimal point (for significant figures), and it's definitely more precise to use 15.99 g/mol for oxygen. I don't think points will be taken off for this during exams, but I'm not totally certain about how much you can round up. H...

octaviahuang1f

I agree with Anna. Also scientific notation can really come in handy sometimes for significant figures. :)
Hope this helps!

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Re: Weak vs strong acids [ENDORSED]

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Re: Test 3 bond length question

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