Search found 34 matches
- Tue Jan 08, 2019 6:54 pm
- Forum: Ideal Gases
- Topic: Pressure units
- Replies: 4
- Views: 524
Re: Pressure units
I believe for Kp we use bars but for solving for anything using the equation Pv=nRT we use atmospheres. Hope this helps :)
- Tue Jan 08, 2019 6:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: liquid vs aqueous
- Replies: 2
- Views: 9040
Re: liquid vs aqueous
Aqueous means a substance is dissolved in water whereas liquid is a pure substance in its melted state. Hope this helps :)
- Tue Jan 08, 2019 6:47 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: aqueous solutions
- Replies: 2
- Views: 323
Re: aqueous solutions
I think it depends on what state the water is in, if it's in a liquid state it can be disregarded and if it's in a gas state like vapor it should be included. This is what I figured from the homework in terms of finding the Kc constant since in lecture we were told to not include solids or liquids. ...
- Sun Dec 09, 2018 9:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: AX3E
- Replies: 18
- Views: 3303
Re: AX3E
The shape is trigonal pyramidal and you base it off of the original tetrahedral shape, for once you remove a bond and add an electron pair to tetrahedral, it becomes trigonal pyramidal.
- Sun Dec 09, 2018 9:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: A.X.E.
- Replies: 4
- Views: 657
Re: A.X.E.
Lone pairs are included in the E part of the equation, for every lone pair you add an E. 2 Lone pairs is E2
- Sun Dec 09, 2018 9:27 pm
- Forum: Sigma & Pi Bonds
- Topic: Amount of sigma bonds
- Replies: 6
- Views: 967
Re: Amount of sigma bonds
The other 2nd bond would have to be a pi bond since there can only be one sigma bond.
- Sun Dec 02, 2018 3:38 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: chelate
- Replies: 4
- Views: 479
Re: chelate
Also chelates can only form when the other atom in the initial ring is adjacent, so in a carbon ring the two ligands attached to the carbon ring must be the carbons next to each other or else there would be too much space and the extra ring won't form.
- Sun Dec 02, 2018 3:31 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Oxidation number
- Replies: 3
- Views: 480
Re: Oxidation number
The sum of the oxidation numbers in atoms of a neutral compound is always 0, and the sum of the oxidation numbers in a polyatomic ion is equal to the ion's charge. So you would look at the charges of the individual atoms and that would be their oxidation numbers. Free elements, such as C by itself, ...
- Mon Nov 26, 2018 9:17 pm
- Forum: Hybridization
- Topic: HW 2.59 Question
- Replies: 2
- Views: 381
Re: HW 2.59 Question
Hey Vana, so both C and O have 3 2SP^2 orbitals and one unhybridized p orbital. The 3 2SP^2 orbitals initially had 1 electron in each orbital but then they're filled up by each sigma bond, whereas the pi bond fills up the unhybridized p orbital. We know it's 2 in front since C and O are on the secon...
- Wed Nov 21, 2018 8:31 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angles for T-shaped, see-saw, and square pyramidal
- Replies: 2
- Views: 356
Re: Bond angles for T-shaped, see-saw, and square pyramidal
Yes, I believe that you're correct in that the lone pairs push the bonds slightly inward, and that the lone pair's don't have their own bond angles. For T-shaped I think we use <90 degrees as the bond angle because we can't say exactly how much it's pushed in, same with seesaw you would have <90 and...
- Wed Nov 21, 2018 8:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square planar shape
- Replies: 1
- Views: 220
Re: Square planar shape
Trigonal bipyramidal involves five regions of electron density whereas square planar involves six, so I used the octahedral shape as my starting point, and as you can see based off the model you can exchange the "top" and "bottom" atom bonds and make them lone pair electrons, whi...
- Wed Nov 21, 2018 8:17 pm
- Forum: Hybridization
- Topic: Help with Confusion
- Replies: 6
- Views: 609
Re: Help with Confusion
Yeah I think the main concepts of Sigma and Pi bonds that we need to know are that Sigma bonds are always the single bonds where two orbitals overlap, where in Pi bonds it's 2 p orbitals overlapping. So a double bond would have one Sigma and one Pi bond. Also one should note that Pi bonds don't allo...
- Mon Nov 19, 2018 1:48 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3890199
Re: Post All Chemistry Jokes Here
How do you post on Chemistry Community?
- Fri Nov 16, 2018 5:28 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: H-Bonding
- Replies: 8
- Views: 2267
Re: H-Bonding
Hydrogen bonds only form with F O and N because they all have very strong partial negative charges due to their electronegativity, which can also be seen when you look at their location on the periodic table. This allows molecules with H and any of those atoms to bond with the strong partial positiv...
- Fri Nov 16, 2018 5:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Octahedral Shape
- Replies: 4
- Views: 894
Re: Octahedral Shape
XeF4 is in fact Square planar. It's VSEPR equation is AX4E2 because it has 4 bonding regions and 2 lone electron pairs. This formula will always yield the square planar shape.
- Fri Nov 16, 2018 5:22 pm
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Bond Strength
- Replies: 3
- Views: 363
Re: Covalent Bond Strength
I believe you are right that as a bond get's longer, it's of weaker strength. Do you have an example which said otherwise? Also note that a double bond would be stronger than a single bond.
- Sun Nov 11, 2018 10:16 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Bonds with Covalent Character
- Replies: 3
- Views: 451
Re: Ionic Bonds with Covalent Character
Yeah, so the electron does't completely transfer to the other side. The positive Na side exerts an attractive force on the Cl electrons, which moves the electron cloud over but isn't a complete transfer of electrons. And that's why there is still some sharing or covalent character between the valenc...
- Sun Nov 11, 2018 10:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Difference in models
- Replies: 2
- Views: 302
Re: Difference in models
Building on what Kyleigh has said, pay attention to the VSEPR formula which is based on the central atom, number of atoms sharing bonds, and number of lone pairs on central atom. Structures with the same formula will take on the same shape, so once you solve for one, you can assume that following st...
- Sun Nov 11, 2018 10:03 pm
- Forum: Ionic & Covalent Bonds
- Topic: Differentiating between Covalent and Ionic
- Replies: 3
- Views: 416
Re: Differentiating between Covalent and Ionic
Atoms in covalent bonds are in a liquid or gas state at room temperature whereas atoms in ionic bonds are in a solid state at room temperature. Covalent bonds are low in polarity whereas Ionic bonds are high in polarity.
- Wed Oct 31, 2018 12:45 am
- Forum: Octet Exceptions
- Topic: FC and Octet Exceptions
- Replies: 1
- Views: 262
Re: FC and Octet Exceptions
Using the correct number of e- is most important, then you work on filling the octets. Elements row 3 and below can occupy more electrons than the octet since they have a hidden d block. Then you focus on reducing the formal charges by looking at double bonds you can create and moving lone pairs aro...
- Wed Oct 31, 2018 12:43 am
- Forum: Lewis Structures
- Topic: Exception to Octet Rule [ENDORSED]
- Replies: 3
- Views: 343
Re: Exception to Octet Rule [ENDORSED]
This is because elements in the 3d row and beyond have n=3 which means L can equal 0,1, and 2 (s,p,d). Elements in the 3rd row actually have access to the d block, allowing them to occupy more electrons, up to 10 more than the octet to be exact. Hope this helps :)
- Wed Oct 31, 2018 12:39 am
- Forum: Octet Exceptions
- Topic: Octet Exceptions
- Replies: 3
- Views: 466
Re: Octet Exceptions
13th column, doesn't need complete octet
3rd row and below, can have up to 10 extra electrons in addition to octet
First 4 elements in periodic table don't have octets to complete
hope this helps :)
3rd row and below, can have up to 10 extra electrons in addition to octet
First 4 elements in periodic table don't have octets to complete
hope this helps :)
- Wed Oct 31, 2018 12:38 am
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 4
- Views: 543
Re: Lewis Structures
Boron doesn't need a full octet because it's in the 13th column, and elements there have stable electron states already.
- Mon Oct 22, 2018 5:45 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39574
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
For Quantum World Part 2 Worksheet, why is 11 D False?
- Sun Oct 21, 2018 6:22 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: KJ/mol-->J
- Replies: 1
- Views: 878
Re: KJ/mol-->J
Divide the number by Avogadro's number to convert to Kj, then multiply by 1000 to convert to J. Hope this helps :).
- Sun Oct 21, 2018 6:19 pm
- Forum: Properties of Electrons
- Topic: Atomic Spectra
- Replies: 2
- Views: 267
Re: Atomic Spectra
The Lyman series involves UV light, and thus it has a higher energy drop and moves all the way down to n=1, whereas Balmer series involves visible energy which is why it only moves to n=2, thus less energy involved as well.
- Sun Oct 21, 2018 6:15 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Shape of Orbitals
- Replies: 3
- Views: 380
Re: Shape of Orbitals
I think we just need to know the basic shapes and understand the concepts. For doing a simple drawing, s is a sphere, p has the two balloons up and down, and d has 4 long balloons going north south east and west. I think you'll only need to know those three, and you can see that as the orbital numbe...
- Sat Oct 13, 2018 7:49 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Writing in Pen
- Replies: 13
- Views: 1049
Re: Writing in Pen
I would say just practice by doing your homework in pen. Getting used to it now will help you in the long run I think. I use to only work in pencil, so I know how you feel, but I would say don't worry too much about making mistakes as you can always cross them out, and focus on solving the Chem prob...
- Sat Oct 13, 2018 7:43 pm
- Forum: Properties of Light
- Topic: Wave vs. Photon
- Replies: 2
- Views: 189
Re: Wave vs. Photon
I think the important takeaway is that light has both the properties of a wave and a particle/photon, depending on the situation. The photoelectric experiment showed that light cannot eject electrons without the correct frequency, showing that it doesn't act like a wave, because if it always acted l...
- Sat Oct 13, 2018 7:34 pm
- Forum: Properties of Light
- Topic: Rydberg Equation
- Replies: 3
- Views: 182
Re: Rydberg Equation
Let's say a question asks to find the wavelength of the electromagnetic radiation that is emitted from an electron which changes from n = 3 to n = 1. You would plug in the two ns' and then solve for wavelength. Sometimes the question would ask for the frequency, which you would have to solve for by ...
- Sat Oct 13, 2018 5:39 pm
- Forum: Administrative Questions and Class Announcements
- Topic: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
- Replies: 135
- Views: 39574
Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]
Thank you very much, will work on these right away!
- Sat Oct 06, 2018 7:22 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactants M11
- Replies: 2
- Views: 905
Re: Limiting Reactants M11
Hey there, wow this was quite the question. So basically, you take the masses you are given of P4 and O2 and convert them to moles by dividing by their respective molar masses. You also compare the P4 moles to the O2 moles by multiplying the P4 moles by 3 since the ratio of P4 to O2 atoms is 1:3. Th...
- Sat Oct 06, 2018 7:10 pm
- Forum: Empirical & Molecular Formulas
- Topic: homework problem E23
- Replies: 2
- Views: 339
Re: homework problem E23
Hi, I believe it is asking for the number of F- ions in moles, they textbook may have just stated the question in a confusing way. Hope this helps :)
- Thu Oct 04, 2018 12:24 pm
- Forum: Empirical & Molecular Formulas
- Topic: Polyatomic Ions
- Replies: 1
- Views: 209
Re: Polyatomic Ions
I think over time we will get use to the most common polyatomic ions. Also if you consider the polyatomic ions that end in -ate as your main ones, different prefixes and suffixes will tell you the different number of oxygen atoms. Per___ate (1 more oxygen) , __ate (most common form), ___ite (1 less ...