CHEMISTRY COMMUNITY

Nikki Bych 1I

Thanks!

Nikki Bych 1I

I forget how Temperature affects the reaction, can someone explain it please?

Nikki Bych 1I

For every reaction, there should be a rate of formation and a rate of consumption.

Nikki Bych 1I

I wish I had more chemistry jokes, but I can only think of them periodically.

Nikki Bych 1I

What would you call a clown in jail?
Silicon

Nikki Bych 1I

I think it's talking about how if there are more collisions, that means the temperature is rising.

Nikki Bych 1I

You can tell if you are given both of the activation energies. If the forward rxn Ae is greater than the reverse rxn Ae, then it is endothermic, because the reverse reaction takes less energy to occur. If the reverse rxn Ae is greater than the forward rxn Ae, then it is exothermic, because the forwa...

Nikki Bych 1I

What happened to the man with sodium chloride and a 9-V in his car?
He was booked for a-salt and battery.

Nikki Bych 1I

What is the most important rule in chemistry?
Never lick the spoon!

Nikki Bych 1I

What did the chemist say when he found 2 isotopes of helium?
HeHe

Nikki Bych 1I

What did one charged atom say to anther?
I've got my ion you.

Nikki Bych 1I

What do you call one tooth in a glass of water?
A one molar solution.

Nikki Bych 1I

Why does the army use acid?
To neutralize their enemy base.

Nikki Bych 1I

I studied exothermic reactions before they were cool.

Nikki Bych 1I

Don't trust atoms, they make up everything.

Nikki Bych 1I

Every dipole has their moment.

Nikki Bych 1I

What do you do with a sick chemist?
If you can't helium and you can't curium, you might as well barium.

Nikki Bych 1I

I wanted to write a joke about the periodic table, but I didn't feel like I was in my element.

Nikki Bych 1I

Did you know you can lower your body temperature to -273 Degrees Celsius and still be 0K?

Nikki Bych 1I

What kind of dogs do chemists have?
Laboratory retrievers!

Nikki Bych 1I

Yes, if you have a balanced reduction half rxn and balanced oxidation half rxn, they will both tell you the number of e- transferred.

Nikki Bych 1I

Yes! Q is just when the reaction is not at equilibrium, but is calculated the same way.

Nikki Bych 1I

Why did the bear dissolve in water?
Because it was a POLAR bear!!!

Nikki Bych 1I

Why do chemistry do well when working with ammonia?
Because it's pretty basic stuff.

Nikki Bych 1I

I don't understand how to form a reduction and oxidation reaction from the equation Cl2-->HClO + Cl2
Thank you in advance!!

Nikki Bych 1I

I am having trouble distinguishing the difference between a state function and an intensive property, they seem very similar to me.

Nikki Bych 1I

Unless the question pertains to identifying what substance it is, we probably won't be asked to identify a superacid/base.

Nikki Bych 1I

I'm not in lecture 2 so I may not be correct, but if he used Q then it was probably because the rxn was not at equilibrium.

Nikki Bych 1I

So first of all, ranking increasing pH means the most H+ ions first, because on the pH scale the more acidic (the more H+ ions) the lower the number. Second, you can do this by finding out the acidity of the solution. For strong acids you can assume complete dissociation, meaning H+ concentration wi...

Nikki Bych 1I

Further, Lavelle mentioned for weak acid/base it should be below 5% protonated as a way to check if you did the problem right.

Nikki Bych 1I

Ka-- acidity
Kb--bacisity
In an such as equation AH + H2O => H3O+ + A-, Ka=products/reactants, and measures the extent to which an acid dissociates in solution (same for Kb but with a basic equation).
p means -log( ).

Nikki Bych 1I

In the compounds listed above, a commonality is multiple H atoms in compounds such as H2CO3

Nikki Bych 1I

Lewis has to do with electrons and bronzed has to do with protons.

Nikki Bych 1I

Is H2O the only amphoteric compound we'll be using? Can anyone find another example of an amphoteric compound

Nikki Bych 1I

I believe if the ligand forms a ring with the TM, it is a chelate

Nikki Bych 1I

Regarding ligands, the transition metal/cation will almost always be the central atom.

Nikki Bych 1I

It is probably a good idea to memorize it, on Lyndon's churro practice questions there are questions with en and ox.

Nikki Bych 1I

Yes, the arrow should be pointing towards the more electronegative atom.

Nikki Bych 1I

I believe they are the same thing as well.

Nikki Bych 1I

Looking at the overall dipole is a good way to determine polarity.

Nikki Bych 1I

Less than 120 degrees, lone pairs alter the bond angle slightly.

Nikki Bych 1I

I don't believe it's a mistake--if you have a electron geometry of trigonal bipyramidal, but 3 lone pairs, the molecular geometry will be linear.

Nikki Bych 1I

1 has the largest dipole. The dipoles cancel in 3, and since the Cl's are further apart in 2, 1 has the largest dipole. Hope this helped!

Nikki Bych 1I

Since the the shape is bent, there must be a lone pair, although you are right, it should be less than 120 degrees.

Nikki Bych 1I

Since the structure is tetrahedral, the overall dipoles do not cancel.

Nikki Bych 1I

Another way to think of it is molecules like BF3 and CH4 are non polar because they are all being pulled equally in each directly (dipoles cancel) but in molecules such as H20, there is an overall dipole so it is polar.

Nikki Bych 1I

Lone pairs are areas of electron density, so they do take up space (like an atom does), but they depress the bond angles more than a normal atom; I think of it as lone pairs needing elbow room!

Nikki Bych 1I

I always think of it as shaded represents an atom coming out of the page and dashed represents an atom going backwards, into the page.

Nikki Bych 1I

Lavelle mentioned in lecture that we don't need to draw them using the dash wedge diagram, just the lewis structures. You just have to be able to recognize the shape based off of how many lone pairs/bonding pairs.

Nikki Bych 1I

I believe that we just have to recognize that when there are lone pairs, the bond angles are depressed. i.e. 3 bonding pairs 1 lone pair, as long as you say bond angles are less than 109.5 degrees because of the lone pier you should be fine.

Nikki Bych 1I

Is it necessary to know how many nodal planes for each orbital for test 2?

Nikki Bych 1I

They are not the same size because there is a different attraction to the nucleus. For example, a cation (one less electron) is smaller because there are less electrons for the positive nucleus to pull on, pulling in the electrons tighter and making the atomic radius smaller.

Nikki Bych 1I

In the book the only degenerate orbitals are one-electron atoms only, but the internet explains it as something different. Is the book's description accurate??

Nikki Bych 1I

So in 1.3, ultimately you are supposed to convert your Joules into Js^-1=watts. I have the joules produced (753.669), but from here do I multiply by hertz to get Js^-1? Thank you!

Nikki Bych 1I

Since we will be given a sheet with all the equations and constants on it, we'll just use the constant to as many sig figs as given :)

Nikki Bych 1I

There was a problem on the homework (1A.5) that asked to list waves in order of of decreasing wavelength, so maybe if we know the range of each type of wave generally.

Nikki Bych 1I

In problem 1B.5, the energy is in eV, and I couldn't find in the book the conversion factor from eV to joules. Thanks in advance!

Nikki Bych 1I

As a general rule of thumb, I tend to balance the "odd" or weird elements first (basically anything that's not C, H or O) and then go C, H and oxygen last.

Nikki Bych 1I

Since the molar mass of gallium is 1/3 the amount of the molar mass of astatine, you need 1/3 gallium atoms for the masses to be equal (1/3 of 210 = 70).

Nikki Bych 1I

An extensive property is a property that changes depending on the amount, such as volume. An intensive property will stay the same no matter how much or little you have of it, such as density. Say you have a cup of water; if you add more water to it, the volume will change but the density will stay ...

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