Search found 31 matches
- Thu Dec 06, 2018 12:07 am
- Forum: Amphoteric Compounds
- Topic: Definition
- Replies: 6
- Views: 621
Re: Definition
Going off of this - can someone explain how we decide whether to use it as a base or an acid? Do you just have to look at the other reactant?
- Thu Dec 06, 2018 12:06 am
- Forum: Conjugate Acids & Bases
- Topic: Clarification of Conjugate Acids and Bases
- Replies: 4
- Views: 568
Re: Clarification of Conjugate Acids and Bases
In the equation it goes
acid +base --> conjugate base + conjugate acid
each acid creates a conjugate base which is 1 hydrogen less than the acid
each base creates a conjugate acid which is 1 hydrogen more than the base
acid +base --> conjugate base + conjugate acid
each acid creates a conjugate base which is 1 hydrogen less than the acid
each base creates a conjugate acid which is 1 hydrogen more than the base
- Thu Dec 06, 2018 12:04 am
- Forum: Lewis Acids & Bases
- Topic: Difference between Lewis and Bronsted
- Replies: 5
- Views: 621
Re: Difference between Lewis and Bronsted
I think the easiest way to recognize is by the presence of a proton. A molecule cannot be a bronsted acid if it doesn't have a hydrogen.
- Thu Nov 29, 2018 8:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR Formula
- Replies: 2
- Views: 356
Re: VSEPR Formula
If you see something like AX 3 E, that means that there are three atoms/molecules surrounding a central atom as well as one lone pair, meaning trigonal pyramidal. A represents the central atom, X represents bonded atoms, and E represents lone pairs. The subscripts represent how many of each of these...
- Thu Nov 29, 2018 8:38 pm
- Forum: Hybridization
- Topic: Lone Pairs in hybridization
- Replies: 3
- Views: 448
Re: Lone Pairs in hybridization
yes - count lone pairs in hybridization!
- Thu Nov 29, 2018 8:34 pm
- Forum: Naming
- Topic: Transition metal oxidation states
- Replies: 3
- Views: 364
Re: Transition metal oxidation states
I am pretty sure that it is because of valence electrons, and there are multiple ways to make transition metals stable.
Also - a different oxidation state can make certain molecules neutral and transition metals are the atoms that can change sign most easily...at least that's my understanding.
Also - a different oxidation state can make certain molecules neutral and transition metals are the atoms that can change sign most easily...at least that's my understanding.
- Fri Nov 23, 2018 12:21 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs on Axial vs. Equatorial Positions
- Replies: 2
- Views: 314
Re: Lone Pairs on Axial vs. Equatorial Positions
They don't occupy the axial positions because the lone pairs want to repel the atoms more than the 90 degrees that set-up would allow. By putting the lone pairs on two of the three equatorial positions, the lone pairs can repel the atoms more effectively and substantially.
- Fri Nov 23, 2018 12:13 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent - Lone Pairs
- Replies: 8
- Views: 963
Re: Bent - Lone Pairs
Are the angles the same or different whether it is one lone pair or two lone pairs in the bent shape?
edit - oops just saw the post above...
edit - oops just saw the post above...
- Fri Nov 23, 2018 12:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Drawing Structures on Test
- Replies: 11
- Views: 999
Re: Drawing Structures on Test
Does anyone know if we are expected to be able to draw the structures with the wedges? Or is it just naming the shape?
- Fri Nov 23, 2018 12:10 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR RULE 3
- Replies: 4
- Views: 468
Re: VSEPR RULE 3
I'm not 100% sure but I think the reason that single and double bonds are both considered 1 area of e- density is because for double bonds as well as single bonds, the e- are still in the one same area. VSEPR counts areas of e- density, and a double bond is 1 area of e- density just as single bonds ...
- Thu Nov 15, 2018 8:41 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length and Resonance
- Replies: 5
- Views: 1742
Re: Bond Length and Resonance
Single bonds are longer than triple bonds because they are weaker. I am pretty sure this is because there is less pull on the electrons by the nuclei of the atoms that are bonded, so the bond is easier to break when it is longer. In resonance structures, all the bonds between elements with resonance...
- Thu Nov 15, 2018 8:37 pm
- Forum: Dipole Moments
- Topic: Induced-dipole
- Replies: 5
- Views: 1864
Re: Induced-dipole
An example of dipole-induced dipole would be when a molecule with a dipole (HCl for example) gets close to a molecule without a dipole. There will be attraction between the positive of the nonpolar molecule and negative part of the dipole (Cl) (or vice versa) - creating a temporary (induced) dipole ...
- Thu Nov 15, 2018 8:32 pm
- Forum: Dipole Moments
- Topic: Induced-Dipole Induced-Dipole
- Replies: 5
- Views: 667
Re: Induced-Dipole Induced-Dipole
hanna_maillard3B wrote:So van-der waals forces work because of induced-dipole induced dipoles ? Do induced-dipole induced-dipole moments affect any other type of bonding or exclusively van-der waals ?
I am pretty sure that induced dipole - induced dipole and Van der Waals forces are two names for the same thing.
- Thu Nov 08, 2018 7:06 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs Covalent Bonds
- Replies: 18
- Views: 1818
Re: Ionic vs Covalent Bonds
Covalent bonds are associated with the sharing of electrons between two nonmetals while Ionic bonds involve the transfer of electrons between a metal and nonmetal, which involves lattice energy. Ionic bonds are extremely stronger than covalent bonds because of the smaller distance between Ionic bon...
- Thu Nov 08, 2018 7:00 pm
- Forum: Dipole Moments
- Topic: Permanent Dipole Moments
- Replies: 4
- Views: 4008
Re: Permanent Dipole Moments
Is there some kind of a cutoff for how to decide whether or not a dipole is permanent?
- Thu Nov 08, 2018 6:54 pm
- Forum: Dipole Moments
- Topic: Polar and Nonpolar
- Replies: 7
- Views: 811
Re: Polar and Nonpolar
Kind of an extension of this question - so the only way to have a nonpolar covalent bond would be if the electronegativity is the same meaning the same element?
- Thu Nov 01, 2018 5:20 pm
- Forum: Resonance Structures
- Topic: Purpose of Resonance Hybrids
- Replies: 4
- Views: 451
Purpose of Resonance Hybrids
I am confused on what resonance hybrids are for. Generally and specifically the Benzene Resonance hybrid...so does it only apply to benzene? And also - are there other resonance hybrids?
- Thu Nov 01, 2018 5:16 pm
- Forum: Lewis Structures
- Topic: central atoms
- Replies: 8
- Views: 793
Re: central atoms
Usually (maybe always??) the atom with the lower ionization energy will also have the lower electronegativity so I guess the answer would be both
- Thu Nov 01, 2018 5:12 pm
- Forum: Electronegativity
- Topic: Periodic Trends
- Replies: 10
- Views: 1244
Re: Periodic Trends
For Ionization energy, electron affinity, and electronegativity it Decreases Down and increases across
For atomic radius I just remember that its the other way around
For atomic radius I just remember that its the other way around
- Thu Oct 25, 2018 9:40 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Spectral Lines and Series
- Replies: 3
- Views: 401
Re: Spectral Lines and Series
Spectral lines show that wavelengths are emitted only at certain frequencies. Then by looking at those specific frequencies, you can figure out what the element is because every element has a unique set of spectral lines (wavelengths).
- Thu Oct 25, 2018 9:37 pm
- Forum: Einstein Equation
- Topic: De Broglie's
- Replies: 4
- Views: 901
Re: De Broglie's
Often it can be the mass of an electron. Just use the mass of whatever the question asks. Also another trick could be to use the mass of whatever has the velocity.
- Thu Oct 25, 2018 9:35 pm
- Forum: Trends in The Periodic Table
- Topic: Ionization Energy
- Replies: 6
- Views: 1748
Re: Ionization Energy
I was wondering the same thing... maybe just an exception??
- Thu Oct 18, 2018 7:53 pm
- Forum: Einstein Equation
- Topic: Units of Energy
- Replies: 5
- Views: 571
Re: Units of Energy
The way that I remember the SI units for a Joule is by writing out the equations from physics
E = F*d
also F=ma
so,
J=(kg*m*(s^-2))*m
J=kg*m^2*s^-2
E = F*d
also F=ma
so,
J=(kg*m*(s^-2))*m
J=kg*m^2*s^-2
- Thu Oct 18, 2018 7:50 pm
- Forum: Photoelectric Effect
- Topic: Threshold energy [ENDORSED]
- Replies: 17
- Views: 2218
Re: Threshold energy [ENDORSED]
Hi Samantha - Threshold energy has to do with the amount of energy required to release an electron from a metal. The threshold energy changes with whatever kind of metal you are using.
- Thu Oct 18, 2018 7:46 pm
- Forum: Properties of Light
- Topic: Rydberg formula
- Replies: 8
- Views: 824
Re: Rydberg formula
I am also confused about the Rydberg formula and which one we are supposed to use. Also - is the Rydberg formula only for Hydrogen?
- Wed Oct 10, 2018 9:17 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Changing Units
- Replies: 10
- Views: 841
Re: Changing Units
When doing molarity questions - you have to do all the calculations in Liters because Molarity is moles/Liters. So, it wouldn't make sense to use mL when molarity uses Liters, in other words, the units would not cancel and you would get an incorrect answer. After the problem is solved, however, it c...
- Wed Oct 10, 2018 9:12 pm
- Forum: Empirical & Molecular Formulas
- Topic: Chemical Formula Element Order
- Replies: 5
- Views: 680
Re: Chemical Formula Element Order
I had this same question... I think that for now it doesn't matter but later on it may start to matter/we will get used to the order in which the elements are listed.
- Wed Oct 10, 2018 9:09 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: % Yield
- Replies: 8
- Views: 1626
Re: % Yield
I don't exactly think that there is a "cutoff" in the lab unless you decided to create your own cutoff for a certain situation? Percent yield is (actual yield/theoretical yield) *100% Actual yield is always going to be less than theoretical yield - so the answer will always be 100% or less...
- Wed Oct 03, 2018 11:01 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: V=n/c
- Replies: 7
- Views: 9249
Re: V=n/c
On an extended note for this -
What is the difference between M and m? All of the similar variables are confusing me... If someone is interested in simply laying out all the different variables related to Molarity that would be amazingly helpful!
What is the difference between M and m? All of the similar variables are confusing me... If someone is interested in simply laying out all the different variables related to Molarity that would be amazingly helpful!
- Wed Oct 03, 2018 10:52 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Moles!
- Replies: 7
- Views: 808
Re: Moles!
My only previous chem class was my sophomore year so even stoichiometry feels foreign. I had asked few friends who are good at chem about converting grams to moles using stoichiometry, and they have done it a few different ways but got the same answer. Does anyone have any good tips on how to set u...
- Tue Oct 02, 2018 2:54 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Moles!
- Replies: 7
- Views: 808
Moles!
I am VERY rusty on the whole concept of moles...and I am finding it difficult to grasp other concepts without fully understanding moles. Does anyone have any advice on what/how to study and review moles? For example - when to use Avogadro's number, what molar mass is for etc. Any good youtube video ...