CHEMISTRY COMMUNITY

Milisuryani Santoso 1L

Its essentially an irreversible process when CO binds to hemoglobin, whereas O2 isn't because it's affinity to bind to heme is much stronger than the O2 molecule.

Milisuryani Santoso 1L

It helps cells create DNA, as well as regulate metabolism. Also according to the book it's the only biological molecule that has a metal-carbon bond.

Milisuryani Santoso 1L

Additionally, hemoglobin is found in the bloodstream while myoglobin is more in muscle cells, but that's more of a fun fact than anything.

Milisuryani Santoso 1L

Also, it's good to remember how to draw it, just in case. Plus it helps with labelling its molecular shape and usage for chemotherapy.

Milisuryani Santoso 1L

Are there any more important common ones besides the ones already listed?

Milisuryani Santoso 1L

The easiest way would probably be burning "clean" coal and turning to alternative energy sources like solar/wind/water/etc. power.

Milisuryani Santoso 1L

I think that acid rain will probably just be used as the background to a question on the final (maybe a acid/base pH thing or whatever), but it's more essential to be aware of it and understand how to calculate pKa in context.

Milisuryani Santoso 1L

ASetlur_3I wrote:What is the pKa value actually describing?

pKa is just the pH of an acid.

Milisuryani Santoso 1L

Additionally, I think it's good to know that pure water @ 25 degrees C is pH=7 (neutral) just for a reference on the test.

Milisuryani Santoso 1L

Essentially, because F is so electronegative, it has an extremely strong hold on H's electron, which thus requires more energy to break. Because HI has a longer bond + I is less electronegative, its easier to break and thus dissociates more than HF.

Milisuryani Santoso 1L

Basically whatever we learned barring hybridization that hasn't yet been on a test will be tested on the next one.

Milisuryani Santoso 1L

How do you tell ML again and can someone explain what it is? ML is the magnetic quantum number (it indicates which orbital the electron is in). It depends on the angular momentum quantum number, or L. Valid values for ML are -L, .. 0, .. L. For example, for a p orbital (angular momentum quantum #=1...

Milisuryani Santoso 1L

Also, regardless of how many bonds you have, there can only be one sigma bond, but possibly multiple pi bonds depending on if its a double or triple bond.

Milisuryani Santoso 1L

005162520 wrote:Why are sigma and pi bonds relevant?

Once you get to o-chem, sigma and pi binds really help one predict how molecules interact and how they work together in organic processes.

Milisuryani Santoso 1L

Pi bonds also prevent atoms from rotating while sigma ones really only keep the atoms connected to each other

Milisuryani Santoso 1L

Water is just really good at dissolving things due to its hydrogen bonding and its polarity thus allows it to do so.

Milisuryani Santoso 1L

There's 3: polar covalent, non polar covalent, and coordinate covalent.

Milisuryani Santoso 1L

Just look at the numbers they give you on the test and base it off of that
.

Milisuryani Santoso 1L

Everything we need will be on the equations sheet, but it would be helpful to remember some of the common ones.

Milisuryani Santoso 1L

Outline 3 should be what the homework is on.

Milisuryani Santoso 1L

Resonance structures are basically a molecule with the same chemical connectivity is the same, but electrons are distributed differently around the molecule.

Milisuryani Santoso 1L

It definitely is possible and could be drawn with the 'fishhook' method. I don't think it's in the scope of chem 14A, however, so I wouldn't worry about it.

Milisuryani Santoso 1L

An easy way to determine ionic character in covalent bonds is looking at the atoms on the periodic table. If the atoms are closer, the more likely it is covalent with the atom of higher electronegativity pulling the shared electrons more closely to itself.

Milisuryani Santoso 1L

Essentially, the more bonds between two atoms just means that the electron density between the two are much higher than atoms with less bonds. Thus, the higher likelihood of electrons in the middle act to pull the positively charged nuclei of the atoms closer together, making it harder to break.

Milisuryani Santoso 1L

For me, I think it's easier just to have a grasp of the most common polyatomic ions and look out for those in the chemical formulas given to you. If there is an ion in it, then it forms an ionic bond and if none, it's covalent.

Milisuryani Santoso 1L

The molecules in gases due to their high energy naturally want to spread out and move around in their environment. When they are pushed together to form a solid, it will naturally take a lot of energy to keep them locked together, which is what lattice energy is.

Milisuryani Santoso 1L

Honestly it really depends. Some ionic bonds are stronger than covalent ones, and the opposite is true in other situations. The only way you can really figure it out is to figure out the energy needed to break each bond and go from there to compare (however generally ionic bonds are harder to break ...

Milisuryani Santoso 1L

Ionic bonds are basically when cations/anions are attracted together by their overall charge, forming a bond. Covalent bonds are when atoms share electrons which also forms a bond.

Milisuryani Santoso 1L

Basically, you can kinda tell if an element will form a cation or anion depending on how many valence electrons they have. For metals, it's faster for them to lose electrons to gain a noble gas like configuration and the opposite is generally true for nonmetals.

Milisuryani Santoso 1L

I like to think that since they're in between metals and nonmetals, they can do both covalent (usually nonmetal bonding) and ionic (usually metal bonding).

Milisuryani Santoso 1L

For me, I like to think that in s orbitals, there's an equal chance for the electron to be anywhere in the sphere, thus making them symmetrical. All the other orbitals (p,d,f) all have increasingly complex shapes on multiple different planes with accompanying nodal planes where electrons have 0 prob...

Milisuryani Santoso 1L

Try going to TA hours if you can! I feel like this helps a lot, especially since you can get your questions answered and worked through right in front of you. Plus, if you still don't understand, you can always just ask right then and there.

Milisuryani Santoso 1L

Personally, I like to take a step back from everything and just breathe. On any test, just do your best and even though you don't get the results you wanted, it's not the end of the world and numbers don't define you. All you need to do is see what you can improve on and try again next time!

Milisuryani Santoso 1L

I don't think it matters which one you use, as long as you know that the original equation is h/4pi. The h bar symbol is just used as a shorthand really for h bar = h/2pi, so it's up to you.

Milisuryani Santoso 1L

Well there definitely has to be a limit, otherwise there'd be atoms that'd become so huge, we'd be able to see them with our naked eyes (which doesn't happen). So, yes, but I don't think we have to know that limit for the scope of this class.

Milisuryani Santoso 1L

Definitely go over the pre/post module assessment questions and make sure you know how to answer those as well. They're probably going to help out a lot foundation-wise and allow you to build on that knowledge to do the hw problems as well.

Milisuryani Santoso 1L

Well, De Broglie's Equation is accurate when it comes to measuring small things like electrons, neutrons, and protons, so we'd assume it'd work for anything that has rest mass. However, as technology is as it is now, we don't have the tools that can measure wavelengths as small as the ones objects w...

Milisuryani Santoso 1L

If I'm not incorrect, black body radiation is radiation that is theoretically emitted from a black body, which absorbs all radiation that falls onto it.

Milisuryani Santoso 1L

Does that mean that if the energy of a photon is greater than or equal to the energy needed to eject an electron, then increasing intensity results in more ejected electrons? Yep! Basically because at that point, increasing intensity means you increase the number of photons with that equal or highe...

Milisuryani Santoso 1L

From what I understand from the back of the book's answer, the wavelength of both particles will be about the same (1.44 pm), so there is no real difference in percent. Therefore, due to their nearly identical weights, you have 0% difference since there's only 3 sig figs. (The answers don't even hav...

Milisuryani Santoso 1L

Is there any example/pdf of what will be given during the test or should I just try and memorize everything we learned up until now?

Milisuryani Santoso 1L

I think you're asking about the difference between red and blue light as in how they're different?. The oscillation in itself is just measured in frequency (Hertz) and red light has a longer wavelength than blue. Therefore, its frequency (oscillations per second) is lower than blue. Hope that helps ...

Milisuryani Santoso 1L

So just to make sure, if I have the TI-36X Pro scientific calculator, would that be alright for a test?

Milisuryani Santoso 1L

I was kind of confused on sig figs for answers to questions, for instance if there was a question like (3.8*4.25)/7 would the answer have 2 sig figs or one? For problems involving only multiplication and division, you just look at the number with the lowest number of sig figs. In this case, that wo...

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