Search found 31 matches
- Sun Jun 10, 2018 10:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Helpful Chart
- Replies: 18
- Views: 1477
Re: Helpful Chart
Just to be clear, they are less than because the loan electron pair pushes the other atoms farther away from it (and thus closer to other atoms). This then results in increasingly smaller angles between atoms as you move left to right along the chart.
- Sun Jun 10, 2018 10:14 pm
- Forum: Bronsted Acids & Bases
- Topic: Oxoacids
- Replies: 4
- Views: 603
Re: Oxoacids
When using a strong acid our chemical equation can use a single arrow to show the reaction correct? This is because it is donating essentially all H+ protons?
- Sun Jun 10, 2018 10:12 pm
- Forum: Lewis Acids & Bases
- Topic: Donating electrons
- Replies: 3
- Views: 581
Re: Donating electrons
It's also important to remember that while acids always donate protons, Lewis acids accept pairs of electrons from Lewis base. Thus remember that acids donate protons but they can also accept thing (i.e. electron pairs).
- Sun Jun 03, 2018 10:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Hybridization and Molecular Shape
- Replies: 1
- Views: 184
Hybridization and Molecular Shape
When determining hybridization is it always reliable to draw the lewis structure, determine the molecular shape, and then find the hybridization formula? What is the relationship between molecular shape and hybridization?
- Sun Jun 03, 2018 10:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone pairs
- Replies: 7
- Views: 773
Re: Lone pairs
In the case of linear shapes when a trigonal bipyramidal has 3 loan pairs or an octahedral has 4 loan pairs the bond angles are determined to be 180 degrees. How do loan pairs cause this?
- Sun Jun 03, 2018 10:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Pi bonds
- Replies: 4
- Views: 573
Re: Pi bonds
When determining pi bonds in double and triple bonds does it matter which bond is "selected" as the pi and sigma bonds?
- Sun May 27, 2018 8:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Types of Bonds
- Replies: 6
- Views: 824
Re: Types of Bonds
I was confused by this too, so here's a helpful website with images of what the bonds look like to demonstrate the different overlapping properties: https://sites.google.com/site/ed350201003/Task
- Sun May 27, 2018 8:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Resonance
- Replies: 7
- Views: 981
Re: Resonance
Also remember to address how bond strength is affected by resonance structures. For instance a double bond in a resonance structure is shorter (and thus stronger) than a regular double bond. This is because the actual structure is a combination of the resonance structures (and thus bonds).
- Sun May 27, 2018 8:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle
- Replies: 10
- Views: 1101
Re: Bond Angle
As a follow up, how do lone pairs affect bond angles? I understand that the lone pair sits more on top of the central atom - but does this always have the same affect on the angles?
- Sun May 20, 2018 10:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polarization
- Replies: 7
- Views: 1068
Re: Polarization
I'm still confused too, but it helps to see how covalently bonded atoms can become ionicly bonded cations or anions. Here's a helpful website:
https://www.diffen.com/difference/Coval ... onic_Bonds
https://www.diffen.com/difference/Coval ... onic_Bonds
- Sun May 20, 2018 10:31 pm
- Forum: Electronegativity
- Topic: Electronegativity vs. Electron affinity
- Replies: 7
- Views: 789
Re: Electronegativity vs. Electron affinity
This also means that electronegativity and electron affinity follow the same periodic trends - increasing as you move up and to the right. This also means the atomic size is decreasing.
- Sun May 20, 2018 10:28 pm
- Forum: Octet Exceptions
- Topic: Radicals [ENDORSED]
- Replies: 6
- Views: 883
Re: Radicals [ENDORSED]
Are there any elements that cannot only have one electron attached? Or are there any that are more likely to have just one in a lewis structure?
- Sun May 13, 2018 10:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: VALENCE ELECTRONS [ENDORSED]
- Replies: 16
- Views: 2026
Re: VALENCE ELECTRONS [ENDORSED]
How do valence electrons influence Lewis structures? Are they represented in any particular way?
- Sun May 13, 2018 10:17 pm
- Forum: Ionic & Covalent Bonds
- Topic: cation vs anion
- Replies: 14
- Views: 3601
Re: cation vs anion
It helps to think of these in terms of a cation makes the ion "more positive" by removing electrons. Becuase an electron is negatively charged, removing it will make the element more positive. Correspondingly, an anion makes an element more negative by adding more electrons.
- Sun May 13, 2018 10:13 pm
- Forum: Ionic & Covalent Bonds
- Topic: VALENCE ELECTRONS [ENDORSED]
- Replies: 16
- Views: 2026
Re: VALENCE ELECTRONS [ENDORSED]
Look at the group of the periodic table that the element is in. For example, Carbon is in group 4 and has 4 valence electrons.
- Sat May 05, 2018 12:46 pm
- Forum: Photoelectric Effect
- Topic: Frequency on Photoelectric Effect
- Replies: 5
- Views: 623
Re: Frequency on Photoelectric Effect
If you do have a high enough frequency (which in turn decreases the wavelength) then increasing the intensity will result in the release of more electrons. This is because more photons are hitting the metal and thus able to eject more electrons. As it says in the post above 10 photons that meet the ...
- Sat May 05, 2018 12:41 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: energy with s,p,d,f
- Replies: 3
- Views: 457
Re: energy with s,p,d,f
I'm not sure I understand your whole question but here's some help on how to read the periodic table. If you look at the s-block there are only two columns, thus you can have 2s^1 2s^2 to get to Beryllium. So the 2 comes from row 2 and the ^1 and ^2 are the electrons (see columns). Similarly, in the...
- Sat May 05, 2018 12:33 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: dilution
- Replies: 4
- Views: 638
Re: dilution
Another note on this topic - I asked my TA what happens when you remove a solute and if that changes the volume. She said that typically the change in volume would be so small we're not expected to calculate the density and correspodning change in volume. However, this calculation density = (mass)/(...
- Sat Apr 28, 2018 3:04 pm
- Forum: DeBroglie Equation
- Topic: Wavelength= (h/p) [ENDORSED]
- Replies: 7
- Views: 1160
Re: Wavelength= (h/p) [ENDORSED]
Just to clarify the De Broglie equation does not work for objects without a rest mass (such as light). If you think about how light always has a constant speed it will never stop and thus never have a resting mass.
- Sat Apr 28, 2018 3:03 pm
- Forum: Properties of Electrons
- Topic: Mass of an Electron [ENDORSED]
- Replies: 4
- Views: 631
Re: Mass of an Electron [ENDORSED]
Specifically, we know that the mass of an electron is 9.1095 x 10^-31 kg and the charge is 1.602 X 10^-19 coulombs. You can also find this on your formula sheet.
- Sat Apr 28, 2018 3:00 pm
- Forum: Properties of Light
- Topic: Equations for light [ENDORSED]
- Replies: 4
- Views: 547
Re: Equations for light [ENDORSED]
Another important thing to note is that light always has the same constant speed (2.99792 x 10^8 m/s). This means any question about what speed light is traveling is actually really easy! Plus we should remember that light has no rest mass and thus cannot be used with the De Broglie equation. It's e...
- Mon Apr 16, 2018 9:26 pm
- Forum: Properties of Light
- Topic: Calculating wavelength [ENDORSED]
- Replies: 4
- Views: 1695
Re: Calculating wavelength [ENDORSED]
Is there ever a time we would look for a speed other than that of light? Or does this equation only ever use c?
- Mon Apr 16, 2018 9:23 pm
- Forum: Properties of Light
- Topic: Calculating wavelength [ENDORSED]
- Replies: 4
- Views: 1695
Re: Calculating wavelength [ENDORSED]
The basic equation c = fλ can be arranged as you would rearrange an equation in math. By moving around the variables you are keeping the equation the same, but making it easier to select for the unknown value you are trying to find. For instance, if I want to find the frequency of a wave I would use...
- Mon Apr 16, 2018 9:17 pm
- Forum: Properties of Light
- Topic: Wavelength [ENDORSED]
- Replies: 9
- Views: 1108
Re: Wavelength [ENDORSED]
Here's a helpful example of measuring a wavelength without using the peak to peak method. If you scroll down there's a great diagram in which the wavelength is measured from a different position on the wave!
https://tests.capnhq.gov/ops/archer_tra ... iation.cfm
https://tests.capnhq.gov/ops/archer_tra ... iation.cfm
- Mon Apr 16, 2018 2:08 pm
- Forum: Photoelectric Effect
- Topic: Threshold Energy [ENDORSED]
- Replies: 12
- Views: 1750
Re: Threshold Energy [ENDORSED]
How does this relate to the concept of darkness versus lightness? Does the release of electrons result in our viewing of light and the color spectrum?
- Mon Apr 16, 2018 2:06 pm
- Forum: Einstein Equation
- Topic: Combining E=hv and c=ƛv [ENDORSED]
- Replies: 7
- Views: 5267
Re: Combining E=hv and c=ƛv [ENDORSED]
v = c/ƛ so E = hc/ƛ
- Mon Apr 16, 2018 2:04 pm
- Forum: Properties of Light
- Topic: Amplitude
- Replies: 3
- Views: 142
Re: Amplitude
To clarify, you square the amplitude to get the intensity of that wave.
- Mon Apr 09, 2018 4:55 pm
- Forum: Significant Figures
- Topic: 300 vs 300. [ENDORSED]
- Replies: 8
- Views: 4605
Re: 300 vs 300. [ENDORSED]
1. non zero = significant digit 1.234 has 4 2. zeros between two significant digits = significant digit 1.002 has 4 3. leading zeros = not significant digits 0.003 has 1 4. zeros following significant digits and a decimal = significant digits 300.0 has 4 0.0030 has 2 5. trailing zeros to the right o...
- Mon Apr 09, 2018 4:49 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Module Assessment Question
- Replies: 3
- Views: 226
Re: Module Assessment Question
Also just a note on working with molarity and liquids: when working with liquids the total solution volume changes (make sure to pay attention to the units your liquid is measured in). In this problem we are dealing with a 250ml flask and a solid solute (as seen with units grams) so the total volume...
- Mon Apr 09, 2018 4:46 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass
- Replies: 9
- Views: 1045
Re: Molar Mass
Can someone please clarify when we use molar mass versus atomic mass?
- Mon Apr 09, 2018 4:36 pm
- Forum: Limiting Reactant Calculations
- Topic: Avogadro's Number
- Replies: 1
- Views: 212
Avogadro's Number
When do I need to use Avogadro's Number?