Search found 31 matches

by joannehaddad
Sat Jun 09, 2018 6:52 pm
Forum: Bronsted Acids & Bases
Topic: Acid-Base Reactions and Ionic Equations
Replies: 2
Views: 260

Re: Acid-Base Reactions and Ionic Equations

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 ...
by joannehaddad
Sat Jun 09, 2018 6:45 pm
Forum: Bronsted Acids & Bases
Topic: J.7
Replies: 2
Views: 181

Re: J.7

OH- is an anion, and Zn is a cation, since it's Zn2+, and so it would go with OH-.
by joannehaddad
Sat Jun 09, 2018 6:44 pm
Forum: Bronsted Acids & Bases
Topic: J.1
Replies: 2
Views: 181

Re: J.1

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.
by joannehaddad
Sat Jun 02, 2018 3:03 pm
Forum: Dipole Moments
Topic: HW 6.1
Replies: 3
Views: 171

Re: HW 6.1

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.
by joannehaddad
Sat Jun 02, 2018 3:02 pm
Forum: Sigma & Pi Bonds
Topic: Detail of Bonds
Replies: 3
Views: 216

Detail of Bonds

What do we need to know about sigma and pi bonds exactly? I'm not really sure the amount of detail necessary to know.
by joannehaddad
Sat Jun 02, 2018 3:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 2
Views: 82

VSEPR

I'm a little confused as how to determine where I place the lone pairs? Are there specific rules for doing so?
by joannehaddad
Sun May 27, 2018 8:26 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 2
Views: 219

Re: Radicals

The radical would probably go on the least electronegative, as the other atom, the more electronegative one, attracts more electron pairs.
by joannehaddad
Sun May 27, 2018 8:25 pm
Forum: Octet Exceptions
Topic: expanded octets
Replies: 5
Views: 253

Re: expanded octets

Yes, with an expanded octet, it is referring to the octet of the central atom!
by joannehaddad
Sun May 27, 2018 8:23 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Contribution in Formal Charge
Replies: 2
Views: 179

Re: Contribution in Formal Charge

It's basically the most stable structure, the one with the lowest energy.
by joannehaddad
Fri May 18, 2018 1:18 pm
Forum: Lewis Structures
Topic: 3.41c
Replies: 2
Views: 99

Re: 3.41c

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...
by joannehaddad
Fri May 18, 2018 1:12 pm
Forum: Resonance Structures
Topic: Resonance Structures [ENDORSED]
Replies: 4
Views: 164

Re: Resonance Structures [ENDORSED]

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 ...
by joannehaddad
Fri May 18, 2018 1:07 pm
Forum: Lewis Structures
Topic: Exceptions to the Octet
Replies: 5
Views: 144

Exceptions to the Octet

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?
by joannehaddad
Sat May 12, 2018 10:25 pm
Forum: DeBroglie Equation
Topic: Bohr vs Speed of Light Equation
Replies: 3
Views: 143

Re: Bohr vs Speed of Light Equation

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...
by joannehaddad
Sat May 12, 2018 10:21 pm
Forum: Photoelectric Effect
Topic: light problem
Replies: 2
Views: 200

Re: light problem

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...
by joannehaddad
Sat May 12, 2018 10:14 pm
Forum: Properties of Electrons
Topic: Electron Affinity
Replies: 4
Views: 263

Re: Electron Affinity

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.
by joannehaddad
Sun May 06, 2018 4:11 pm
Forum: *Black Body Radiation
Topic: Midterm?
Replies: 3
Views: 423

Re: Midterm?

You don't need to know this for the midterm
by joannehaddad
Sun May 06, 2018 4:10 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Orders?
Replies: 2
Views: 116

Re: Electron Configuration Orders?

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.
by joannehaddad
Sun May 06, 2018 4:08 pm
Forum: Properties of Light
Topic: The visible spectrum
Replies: 4
Views: 207

Re: The visible spectrum

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.
by joannehaddad
Sat Apr 28, 2018 4:08 pm
Forum: Quantum Numbers and The H-Atom
Topic: What do l and m represent? [ENDORSED]
Replies: 6
Views: 196

What do l and m represent? [ENDORSED]

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.
by joannehaddad
Sat Apr 28, 2018 4:05 pm
Forum: Properties of Light
Topic: Energy difference in excited electrons
Replies: 3
Views: 109

Re: Energy difference in excited electrons

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...
by joannehaddad
Sat Apr 28, 2018 4:02 pm
Forum: DeBroglie Equation
Topic: Conversion [ENDORSED]
Replies: 2
Views: 134

Re: Conversion [ENDORSED]

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...
by joannehaddad
Sun Apr 22, 2018 11:12 pm
Forum: Properties of Light
Topic: Homework 1.5
Replies: 6
Views: 175

Re: Homework 1.5

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.
by joannehaddad
Sun Apr 22, 2018 11:10 pm
Forum: DeBroglie Equation
Topic: Quanta
Replies: 5
Views: 213

Quanta

Can someone explain what quantum really means? Like how do "quanta" related to what we're learning?
by joannehaddad
Sun Apr 22, 2018 11:09 pm
Forum: Einstein Equation
Topic: Joules unit conversion [ENDORSED]
Replies: 2
Views: 113

Joules unit conversion [ENDORSED]

I was just wondering what the unit conversion was for Joules? Something with kg and m and s?
by joannehaddad
Sun Apr 15, 2018 2:40 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electron Energy Levels
Replies: 3
Views: 107

Re: Electron Energy Levels

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.
by joannehaddad
Sun Apr 15, 2018 2:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework 3
Replies: 3
Views: 108

Homework 3

Does anyone know what this week's homework should be for? Like from which outline do we pick homework questions? Thanks!
by joannehaddad
Wed Apr 11, 2018 2:16 pm
Forum: SI Units, Unit Conversions
Topic: Avagrado's Number [ENDORSED]
Replies: 6
Views: 312

Re: Avagrado's Number [ENDORSED]

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...
by joannehaddad
Sun Apr 08, 2018 9:26 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy vs Precision
Replies: 23
Views: 703

Re: Accuracy vs Precision

Precision is how close to each other they are, and accuracy is how close to the true value they are.
by joannehaddad
Sun Apr 08, 2018 9:24 pm
Forum: SI Units, Unit Conversions
Topic: Avagrado's Number [ENDORSED]
Replies: 6
Views: 312

Re: Avagrado's Number [ENDORSED]

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...
by joannehaddad
Sun Apr 08, 2018 9:09 pm
Forum: SI Units, Unit Conversions
Topic: Sig figures
Replies: 9
Views: 306

Re: Sig figures

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.
by joannehaddad
Sun Apr 08, 2018 9:08 pm
Forum: SI Units, Unit Conversions
Topic: Sig figures
Replies: 9
Views: 306

Re: Sig figures

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.

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