CHEMISTRY COMMUNITY

joannehaddad

Okay so, for the overall equation, you write the products of the reactants. In this case, an acid and a base produce a salt and water. Once you have formed water, the remaining elements form the salt. In this case, the salt would be NaF. For the ionic equation, you dissociate the strong acid or the ...

joannehaddad

OH- is an anion, and Zn is a cation, since it's Zn2+, and so it would go with OH-.

joannehaddad

H2SO3 is one of the strong acids that we need to know. It's a strong acid because it is polyprotic, and dissociates completely. NH3 is a weak base that we also just need to know.

joannehaddad

I think it's because the Br atoms are all bonded in an equal manner to the C in the center, and so there isn't really temporary dipole moments.

joannehaddad

What do we need to know about sigma and pi bonds exactly? I'm not really sure the amount of detail necessary to know.

joannehaddad

I'm a little confused as how to determine where I place the lone pairs? Are there specific rules for doing so?

joannehaddad

The radical would probably go on the least electronegative, as the other atom, the more electronegative one, attracts more electron pairs.

joannehaddad

Yes, with an expanded octet, it is referring to the octet of the central atom!

joannehaddad

It's basically the most stable structure, the one with the lowest energy.

joannehaddad

The way this is written actually tells you how to draw it out! Typically, the chemical formula wouldn't have the carbons written out separately unless it was expressing how to draw it out. Basically, follow the chemical formula from left to right. H2C(NH2)COOH The first section is H2C, which is basi...

joannehaddad

I would believe it's through trial and error. But usually, the quickest way to do it in my opinion is to see what is different. For example, if you're drawing a lewis structure for something bonded to 4 oxygens, with 1 single bond and 3 double bonds to oxygen), and so the resonance structures would ...

joannehaddad

The 3rd row elements and below can expand their octet, but I was wondering if there was a limit to how many extra electrons we can add to these elements?

joannehaddad

Typically, looking at the values you already have really helps. For example, if all you have is the wavelength, and the question mentions light, you would use the speed of light equation. If the question asks for frequency, and instead gives you the energy, then you can use the Bohr frequency equati...

joannehaddad

In general, conversions can be kind of tricky, and so I have this method of using dimensional analysis in order to guarantee I do the conversion correctly. Let's say I'm trying to convert from meters to nanometers, and I have 4.3 \times 10^{-7} meters. I know that 1 nanometer is 10^-9. So, I can set...

joannehaddad

The trend for electron affinity is that it increases across a period and decreases down a group, so when answering questions phrased like that, you could just use the trend! Also, electron affinity is how many energy is spent or released when a neutral atom gets an electron added to it.

joannehaddad

You don't need to know this for the midterm

joannehaddad

To double check your answer, make sure that your configuration is written in the order of the n - value, so all the sub-shells associated with 3 are put before any of the sub-shells associated with 4, for example.

joannehaddad

The line spectrum shows the specific wavelengths that are being absorbed/emitted, whereas the continuous spectrum shows a continuum of wavelengths. A line spectrum is discrete, while the continuous spectrum isn't.

joannehaddad

I'm just a little confused as to what the letters l and m represent? I know that n is the energy level, but what are l and m? Thank you.

joannehaddad

When the two n values aren't given, one will be usually given in a hidden way. The question might mention the series that's used or the part of the spectrum. For example, the question might say the Lyman series (and then you would know that the value of n we are reaching is n=1), or that it's in the...

joannehaddad

Glad you figured out your mistake! For the future though, I like to use dimensional analysis for my conversions as to avoid any mistakes or confusion. I use the following set up. Let's say I'm trying to convert from meters to nanometers, and I have 4.7\times 10^{-7} meters. I know that 1 nanometer i...

joannehaddad

Keep in mind that the relationship between frequency, energy, and wavelength is as follows:

The longer the wavelength the lower the frequency and that means less energy.

joannehaddad

Can someone explain what quantum really means? Like how do "quanta" related to what we're learning?

joannehaddad

I was just wondering what the unit conversion was for Joules? Something with kg and m and s?

joannehaddad

The energy levels decrease because the electrons are further away from the nucleus, where the protons are. That means that less energy is needed to remove electrons because the attraction between the protons and electrons is weaker due to increased distance.

joannehaddad

Does anyone know what this week's homework should be for? Like from which outline do we pick homework questions? Thanks!

joannehaddad

It's usually for the number of molecules or atoms, depending on the question, but if you have something that asks for the number of molecules AND then the number of atoms, you can do the following. You would first use Avogadro's constant for the number of molecules, then you multiply that by the li...

joannehaddad

Precision is how close to each other they are, and accuracy is how close to the true value they are.

joannehaddad

It's usually for the number of molecules or atoms, depending on the question, but if you have something that asks for the number of molecules AND then the number of atoms, you can do the following. You would first use Avogadro's constant for the number of molecules, then you multiply that by the lit...

joannehaddad

If you're adding, you use the number with the least number of decimal places as your determinant for the number of decimal places for your answer. Meanwhile, if you're multiplying, the one with the least number of SF should be used to determine the number of SF for the answer.

joannehaddad

If you're adding, you use the number with the least number of decimal places as your determinant for the number of decimal places for your answer. Meanwhile, if you're multiplying, the one with the least number of SF should be used to determine the number of SF for the answer.

CHEMISTRY COMMUNITY

Search found 31 matches

Re: Acid-Base Reactions and Ionic Equations

Re: J.7

Re: J.1

Re: HW 6.1

Detail of Bonds

VSEPR

Re: Radicals

Re: expanded octets

Re: Contribution in Formal Charge

Re: 3.41c

Re: Resonance Structures [ENDORSED]

Exceptions to the Octet

Re: Bohr vs Speed of Light Equation

Re: light problem

Re: Electron Affinity

Re: Midterm?

Re: Electron Configuration Orders?

Re: The visible spectrum

What do l and m represent? [ENDORSED]

Re: Energy difference in excited electrons

Re: Conversion [ENDORSED]

Re: Homework 1.5

Quanta

Joules unit conversion [ENDORSED]

Re: Electron Energy Levels

Homework 3

Re: Avagrado's Number [ENDORSED]

Re: Accuracy vs Precision

Re: Avagrado's Number [ENDORSED]

Re: Sig figures

Re: Sig figures