CHEMISTRY COMMUNITY

Darren1j

Why did the white bear dissolve in water?........Because it was polar! ( no? okay)

Darren1j

You think you’re a 10? On the pH scale, maybe — because you’re basic.

Darren1j

Why do chemists favor nitrates?
Because they are way more affordable than the day rates!

Darren1j

when potassium and oxygen went on their first date, it turned out fine. The second time that oxygen went on a date with potassium it was OK2

Darren1j

Nick P 3D wrote:H2O is water and H2O2 is hydrogen peroxide.
What is H2O4?

Drinking

Day 5 still trying to figure out the meaning of this joke.

Darren1j

For the longest time I kept getting it wrong because I didn't realize total pressure meant add all of the new equilibrium values.

Darren1j

In relation to this topic, why do we say that two reactants or products have the same x value. Don't different compounds have different amounts used in a reaction ( such as a limiting reactant)?

Darren1j

Gold is my favorite part of the periodic table because it is AU-some!

Darren1j

I need someone to look after my electron today, do you mind keeping a ion it for me?

Darren1j

I was confused as to what the K value means for the reverse reaction, but this explanation cleared it up a lot because both reactions take place simultaneously.

Darren1j

Two of the sapling questions revolve around K and change in enthalpy. Thus in reactions with a + change in enthalpy, they are endothermic, and increasing the temperature increases K. In a reaction with a negative change in enthalpy, it is exothermic, and an increase in temperature decreases K.

Darren1j

I just set up my problem like [HI^2]/ [H2][I2] =53.3. I know this doesn't yield the right answer, but why?

Darren1j

Why is it 2x. I thought the fact that there is 2HI is accounted for in the HI^2?

Darren1j

Basically if this class follows basic grading scales (93% for A, etc) then you can miss 35 points total to get an A and 50 points for an A-. This is only IF it follows the way other classes do it, but it very well could be different.

Darren1j

I've been going back and doing the textbook problems and found a bunch of the midterm questions on there. Dr. Lavelle doesnt lie haha.

Darren1j

What does a chemist say when in pain? "Ouch that HERTZ!"

Darren1j

Why would Dr. Lavelle be like every other professor and not dance at the start of lectures? If he didn't, he'd be pretty Basic.

Darren1j

This is a great tip! Has anyone come up with one for strong bases?

Darren1j

Don't worry guys, I'm working on a still image magnifying program to figure out this intense problem.

Darren1j

I've heard people say its good to take it with chem 14c. Would anyone recommend taking it over the summer or would taking it during the year be better?

Darren1j

By studying homework problems, are you referencing sapling or the textbook?

Darren1j

Having retuned from taking the section on coordination compounds and Iron, being rusty on chemistry is a pun in itself.

Darren1j

on the sheet, theres the two names for every ligand. Why did IUPAC decide to change the names?

Darren1j

What is a cation afraid of?
.... A dogion.

Darren1j

Wish me luck guys, I'm planning on being at a session everyday this week. After this midterm, I am confident in myself but know that I made plenty of easy mistakes. I have faith in all of you!

Darren1j

Our tradition is that my mom gets to not cook, and every one else in the family has to impress her with our creations. We try to be creative, and this year we tried variations of mac and chees, mashed potatoes, BBQ turkey and ribs, brussels sprouts etc. I personally never really cook so it is my one...

Darren1j

I usually set a time the day before a test to STOP studying and start relaxing. Theres a trade off between studying and de stressing, and if you cram too much the day before, the balance will get disrupted. You should do all the textbook problems that you can, and go to as many workshop, US, step up...

Darren1j

Also, how can you calculate what grade you need on the final to get an A?

Darren1j

Anyone know how many questions will be on the final?

Darren1j

I am wondering whether to wait on switching one of my classes to not overlap with one of his chem lectures. Would the midterms probably be in the middle of the week (wednesday)? Was this how it was in the past?

Darren1j

Speaking of memorizing the shapes, does anyone know the scientific origination of the sea saw VSEPR shape? It seems like a pretty unacademic term which makes it funny to learn about.

Darren1j

Why are lone pairs more "diffuse" or take up a larger space than bonding pairs do? Since they all are areas of electron density

Darren1j

have you heard the new remix of girls just want to have fun? It goes something like "Hydrogens' just want to have FON..."

Darren1j

I had this same question and I think there's a reason for that difference. In this case H-F H-F, I think its classified as a hydrogen bond and therefore would be -20 but other dipole-dipole interactions that are not hydrogen bonding would be around -2. H Bond is Dipole-Dipole, but dipole- dipole doe...

Darren1j

I just wanted to ask, why do molecules have fluctuating electron densities? N2 should both be equally electronegative but what causes fluctuations? (as it relates to Van der waals forces)

Darren1j

Like the above question asked, did Dr. Lavelle mention that 14b will be asynchronous as well?

Darren1j

Are you made of copper and tellurium? Because you are Cu Te

Darren1j

The kids were mad at their teacher because they wanted to know why they're answer was incorrect. The chemistry teacher replied, " I am a chem teacher, if I don't have a solution, I'll make one up!."

Darren1j

Could someone explain the differences in molecular structure between increasing anion vs increasing cation size? Also, How does polarizing power relate to distortion?

Darren1j

Are radicals only produced when a large amount of energy is provided to make the bonds break? Why doesn't the compound break into two stable molecules instead?

Darren1j

I had this same question so I was wondering if someone can provide some more recent insight. Or do the same ideas mentioned earlier still hold true?

Darren1j

I was also going to ask if Hund's rule applies to Lewis dot structures because Lavelle had shown Oxygen with 3 pairs of electrons rather than 2 pairs and 2 single electrons around the O.

Darren1j

can someone simply explain why one is stronger than the other.

Darren1j

Helium dimer seems like the funniest of molecules because he2 would be like He He.

Darren1j

What kind of dogs does Dr.Lavelle have? I'm going to take a wild guess and say laboratory retrievers

Darren1j

How do you know whether an atom has to gain electrons to fill its shell to become stable, or lose enough electrons to drop to the lower shell to be most stable?

Darren1j

Referring to general atomic radius, why does gaining an electron make the radius bigger and losing an electron make the radius smaller?

Darren1j

Hey, I have question from this same module. Question 30. "Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. .... What is the frequency of the incident light on the sodium metal surface?" Are you s...

Darren1j

I think its best to spread out studying through the week and to do all the things that the people above had mentioned. Read the textbook before the lecture, and then try to do the hw problems. If you want more practice try the audio-visual focus assignments and attend some of the over 40 hors of hel...

Darren1j

I told this one to my mom earlier ^. Sadly, I got no reaction :(

Darren1j

I'm sad that the jokes on here have slowed down. They used to be posted everyday, but now they only happen periodically.

Darren1j

This question asks "How many electrons in an atom could have these sets of quantum numbers?"
a) n= 2
b) n=5, l=1
c)n=7, l=1 m (subscript l) =-1

Can someone clarify how to use the n and l values for this question and their application in general.

Darren1j

I understand what the uncertainty is, because we cannot measure the exact momentum and position of an electron but how do they even determine the "amount" of uncertainty.

Darren1j

So I remember him saying R= 3.29x10^15hz, but when I look it up online it says it is 1.0874x10^-7 m^-1. Are they the same in different units?

Darren1j

The posts above ^ helped me figure this out. Basically, going from a higher level to a lower level causes spectral lines. To find the range of wavelengths, you must use the Rydberg equation. You use the n=7 to n=6 for the first wavelength and n=7 to n=1 for the second wavelength. The equation is v (...

Darren1j

Going forward then, would we use the equation or the multistep process for these problems?

Darren1j

A question to anyone in 14a currently or who have already taken the class. How prepared are you for the tests by just watching the lectures, attending discussions and doing the sapling homework. Does reading the textbook thoroughly help significantly? What are ways you have found to be successful in...

Darren1j

If it absorbs all light, and you need light to be reflected off an object to see it, would a black body be ... invisible? How would that work? In fact, how would a black hole look through a telescope if we could get near one?

Darren1j

If the energy of the light is equal to the energy needed to remove an electron, how much energy is left for the electron to travel with (its velocity)?

Darren1j

Why does combustion always result in H2O and CO2 and not other compounds?

Darren1j

I get that the name is supposed to give you information about the compounds and molecules in it, but can someone explain how you would get it from the compound name OP had mentioned above? Like how would you know the number of C, H and O's?

Darren1j

Some elements of the periodic table have 4 sig figs as their molar mass and others have far more. When calculating the molar mass of a compound, how many sig figs should there be or number be rounded to?

Darren1j

A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."

Darren1j

Did you hear oxygen went on a date with potassium? It went OK..

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