CHEMISTRY COMMUNITY

Hope_Pham_1G

If you have 0.550 M Na2O solution, does this translate to 0.550 M of NaOH? If so, why does pOH = -log[0.550] yield such a small value?

Hope_Pham_1G

Given the abbreviate structure, I'm not sure where all the hydrogen atoms belong, and how to find the approximate bond angles for this molecule.

Hope_Pham_1G

How can you tell the coordination number of the center Fe atom? Why are there solid and dotted lines extending towards the N atoms?

Hope_Pham_1G

Why can there be two pi bonds but not two sigma bonds.

Hope_Pham_1G

How come double bonds and triple bonds have pi bonds?

Hope_Pham_1G

Are ligands always nonmetal atoms?

Hope_Pham_1G

Is the VSEPR model connected to determining sigma and pi bonds? If so, how?

Hope_Pham_1G

Do you know if these types of molecules (molecules with lone pairs) be tested?

Hope_Pham_1G

Will we learn the VSEPR model for molecules with one or more lone pair? So far, we've only learn the basic geometry for molecules with zero lone pairs.

Hope_Pham_1G

"When trying to minimize the formal charge, how do you know which element you should minimize first?"

According to my observation, it seems as if altering the bond arrangements affects the formal charge of multiple elements simultaneously. I don't think there is a specific order.

Hope_Pham_1G

My chem puns rarely get a reaction.

Hope_Pham_1G

A Hug without u
Hg
is just mercury

Hope_Pham_1G

The formal charge is used to discover the most stable Lewis structure. That structure will have the least number of formal charges not equal to zero. Resonance structure represents the various locations of the electron pairs. The electron can go back and forth between atoms.

Hope_Pham_1G

I don't believe we are expected to know this for Chem 14A, but one of the TAs mentioned a simplified version in which benzene is represented by a hexagon with three double bonds. The carbons are implied to be located at each point with the correct amount of hydrogen atoms attached.

Hope_Pham_1G

ClO2 is drawn O-Cl-O.

Hope_Pham_1G

l can equal values from 0 to n-1. That means l can equal 0, 1, 2, 3, and 4 but NOT 5 or higher for this homework problem. l=2 refers to the electron(s) in a specific subshell.

Hope_Pham_1G

For homework, I like to use the more accurate value for Planck's constants. For tests, I use 6.626 x 10^(-34) because the tests are timed, and it's faster to input this version.

Hope_Pham_1G

You can think of the equation, E = hc/λ, as a combination of two equations: E = hv and c = λ v
From the speed of light equation, you can rearrange the variables to solve for frequency: v = c/λ. When you substitute c/λ for v, you get E = hc/λ.

Hope_Pham_1G

A few variations from this week's homework problems (depending on which values are given):
E = hv
hc / v

c = λ v

λ = c/v
λ = hc / E
λ = h / p
λ = h / mv

v = c/λ
v = h / E

(v here represents frequency except for the de Broglie equation)

Hope_Pham_1G

I heard oxygen and magnesium were going out and I was like OMg!

Hope_Pham_1G

You must be a compound of beryllium and barium...because you’re a total BaBe

Hope_Pham_1G

When performing dimensional analysis, why are sig figs applied to each 'step' and not just the final answer? Won’t this result in a less accurate final answer?

Hope_Pham_1G

In dilutions, the value of n, the moles of solute, ALWAYS remains the same. That is why N(initial) = N(final). And thus, M(i)V(i) = M(f)V(f). V(f) also, is the value of the initial solution PLUS the additional solution required for diluting.

Hope_Pham_1G

When visualizing accuracy, think of a bulls-eye target with many shots near the center, but scattered within the radius of the bulls-eye in any direction. The results appear very disbursed. When visualizing precision, think of a bulls-eye target with many shots clumped together, but not necessarily ...

Hope_Pham_1G

100 grams is merely a value that facilitates the conversion from mass percentage composition to actual mass composition. Rather than multiplying the percentage by 100 (and essentially only moving decimal points), you multiply by the specific given grams of the sample.

Hope_Pham_1G

The mass of oxygen is sometimes not given. You should check to see if this the case by comparing the percentage mass to total mass. Don't forget to subtract the mass composition of the given elements from the total to determine the mass of oxygen. The mass of oxygen is sometimes not given due to the...

Hope_Pham_1G

A fast way to know whether to increase the stoichiometric coefficient of an equation is recognizing that an odd number of elements such as oxygen on one side does not match the even number of say O2 (oxygen as a diatomic molecule).

Hope_Pham_1G

A fast way to know whether to increase the stoichiometric coefficient of an equation is recognizing that an odd number of elements such as oxygen on one side does not match the even number of say O2 (oxygen as a diatomic molecule).

Hope_Pham_1G

The molarity formula is moles of solute (n) divided by liters of solution (V). The units of molarity is mol/L (M). M can be substituted with c, which indicates a broader calculation of concentration.

CHEMISTRY COMMUNITY

Search found 29 matches

Calculating pH of a solution given molarity

Methyl-2-Cyanoacrylate

Heme complex structure_coordination number

Re: How to identify pi and sigma bonds

Re: σ bonds

Re: Coordination compound

Re: VSEPR confusion

Re: Bond angle

Re: Any Other Shapes?

Re: formal charge

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: Resonance Structures and Formal charges

Re: Resonance structure of benzene

Re: Formal charge of ClO2- [ENDORSED]

Re: Principle quantum number and orbital angular momentum quantum number

Re: Planck's Constant Value [ENDORSED]

Re: Difference Between Equations [ENDORSED]

Re: Equations for light [ENDORSED]

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Sig Fig Accuracy [ENDORSED]

Re: dilution

Re: Accuracy vs Precision

Re: Mass percentage

Oxygen "missing" in mass percentage composition questions

Re: Fastest way to balance chemical equation

Re: Fastest way to balance chemical equation

Re: Review Question [ENDORSED]