Search found 31 matches
- Sun Dec 09, 2018 10:49 pm
- Forum: Sigma & Pi Bonds
- Topic: Amount of sigma bonds
- Replies: 6
- Views: 939
Re: Amount of sigma bonds
There is only one sigma bond because every bond thereafter is a pi bond. Pi bonds form when non-hybridized orbitals bond with one another.
- Sun Dec 09, 2018 10:48 pm
- Forum: Ionic & Covalent Bonds
- Topic: boiling point
- Replies: 3
- Views: 560
Re: boiling point
Boiling point refers to the breaking of intermolecular forces that hold a substance together. The stronger the intermolecular force, the harder it is to boil a liquid/solid into a gaseous state. Hydrogen bonding is the strongest, followed by dipole-dipole, then london dispersion.
- Sun Dec 09, 2018 10:46 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: polarizing power
- Replies: 3
- Views: 688
Re: polarizing power
Polarizing power refers to a cation's pull of electrons from its bonded anion. Polarizability refers to the anion's ability to be polarized by a cation. They are opposites of one another.
- Sun Dec 09, 2018 10:44 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic vs.covalent bonding
- Replies: 4
- Views: 738
Re: Ionic vs.covalent bonding
Ionic bonds are mostly between metals and nonmetals, basically anions and cations. Covalent bonds are normally between two nonmentals. Ionic bonds form salts and covalent bonds form molecules.
- Mon Dec 03, 2018 11:33 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic vs ionic radius
- Replies: 6
- Views: 941
Re: Atomic vs ionic radius
Anions are bigger because they have more electrons. Cations are smaller because they have less electrons. As a result, their radius is different than when they're just a normal, non-charged atom. Ionic radius = for cation, anions; atomic radius = for non-charged.
- Mon Dec 03, 2018 11:29 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Lone pair location
- Replies: 3
- Views: 756
Re: Lone pair location
Lone pairs tend to hog up a lot of space. They end up pushing down on the bonded molecules due to their repulsion. This results in differing shapes for molecules that have lone pairs as compared to having none.
- Mon Dec 03, 2018 11:28 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Sigma and Pi Bond with Hybridization
- Replies: 2
- Views: 570
Re: Sigma and Pi Bond with Hybridization
Single bonds are always sigma bonds. Double bonds are one sigma, one pi. Triple bonds are one sigma, two pi. Sigma bonds are bonds that overlap with one another and are easily movable/rotatable. Pi bonds are bonds that are parallel with one another and are not movable. As a result, single bonds are ...
- Sun Nov 25, 2018 9:14 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bent/Angular Shape
- Replies: 4
- Views: 514
Re: Bent/Angular Shape
Yes, they are the same. However, I would use "bent" instead of "angular" cause bent is the one that is most commonly used.
- Sun Nov 25, 2018 9:11 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: Difference in Electronegativity
- Replies: 3
- Views: 433
Re: Difference in Electronegativity
Yes, we will have to know what the bonds are based on the electronegativity differences. There should be a chart in our notes that covers this topic, so memorizing it would be good.
- Sun Nov 25, 2018 9:09 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: hydrogen bonding
- Replies: 4
- Views: 850
Re: hydrogen bonding
Hydrogen bonding is a type of intermolecular force, which means attracting forces between molecules. This is different from intramolecular forces, which happen in the molecule. Hydrogen bonding is very important because it is what gives water it's cohesiveness and adhesiveness.
- Mon Nov 19, 2018 10:06 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipole moments
- Replies: 8
- Views: 3298
Re: Dipole moments
It depends on the shape of the molecule at hand. If the molecule is perfectly symmetrical, then forces of equal strengths will cancel out. If the molecule isn’t perfectly symmetrical then strengths will migrate to one direction. Examples of symmetrical shapes are tetrahedral and linear while example...
- Mon Nov 19, 2018 10:04 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Cations vs anions
- Replies: 3
- Views: 405
Re: Cations vs anions
Cations have less electrons while anions have more. This can result in removing a lone pair or adding a lone pair, which causes differences in VSEPR shape simply because lone pairs push repel nearby bonded elements.
- Mon Nov 19, 2018 10:00 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: lone pair influence on shape
- Replies: 12
- Views: 4207
Re: lone pair influence on shape
Lone pairs take up a lot of space and have a ton of repulsion around them so the bonded elements get pushed away. As for bent vs linear, linear is as it sounds like. A straight line with bond angles of 180 degrees. This only occurs when there are no lone pairs to cause repulsion. When there are lone...
- Sun Nov 11, 2018 2:46 pm
- Forum: Electronegativity
- Topic: Electronegativity
- Replies: 4
- Views: 558
Re: Electronegativity
Electronegativity helps with molecule shape in the way that it allows you to figure out which molecule is the central one. The least electronegative molecule tends to be the one in the center.
- Sun Nov 11, 2018 2:45 pm
- Forum: Resonance Structures
- Topic: Drawing resonance
- Replies: 17
- Views: 1817
Re: Drawing resonance
Yes, it is necessary to draw all the resonance structures in order to show that the overall bonds of the molecule are equal, not one greater than the other.
- Sun Nov 11, 2018 2:41 pm
- Forum: Lewis Structures
- Topic: Formal charges
- Replies: 15
- Views: 1212
Re: Formal charges
It is not necessary but it is a good way to figure out if your lewis structure can be improved or not. I would do it just in case. If the question asks specifically for you to add the formal charges, then do so, but if not then it is your choice.
- Sun Nov 04, 2018 5:14 pm
- Forum: Sigma & Pi Bonds
- Topic: determining which bonds are in a molecule
- Replies: 4
- Views: 492
Re: determining which bonds are in a molecule
If you're referring to a lewis structure, then yes, counting each valence electron is the way to go. However, if you're looking to see if a molecule has ionic or covalent bonds then you look at the electronegativity differences.
- Sun Nov 04, 2018 5:10 pm
- Forum: Properties of Light
- Topic: Standard Units
- Replies: 8
- Views: 758
Re: Standard Units
Wavelength is almost always in meters (standard) or nanometers (10^-9 m). It is portrayed by the greek letter lambda, which looks like a curvy upside v almost.
Anything in m/s is ALWAYS going to be velocity. Under no circumstances will it ever be a wavelength.
Anything in m/s is ALWAYS going to be velocity. Under no circumstances will it ever be a wavelength.
- Sun Nov 04, 2018 5:07 pm
- Forum: Properties of Light
- Topic: Photoelectric Effect - waves vs. photons
- Replies: 3
- Views: 611
Re: Photoelectric Effect - waves vs. photons
For the photoelectric effect, light is seen as a particle. Increasing the intensity of light increases the number of electrons ejected, only if the frequency is large enough. Large frequency correlates to small wavelength, therefore even if you increase the intensity of light for a big wavelength of...
- Sun Oct 28, 2018 6:59 pm
- Forum: Dipole Moments
- Topic: Intermolecular forces
- Replies: 2
- Views: 428
Re: Intermolecular forces
Intermolecular forces are forces between molecules most of the time resulting from dipole moments. They are different from intramolecular forces which are chemical bonds that hold atoms together. Intermolecular forces are far weaker and can be easily broken apart for the most part. Hydrogen bonds, l...
- Sun Oct 28, 2018 6:56 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Bonds vs Covalent Bonds
- Replies: 7
- Views: 693
Re: Ionic Bonds vs Covalent Bonds
Biology, being the study of organisms, is focused on the life processes in organisms. For the most part, organisms are made up of mostly water and thus the focus of biological chemical reactions are ones that occur in an aqueous environment. Ionic bonds are indeed stronger because of equal sharing o...
- Sun Oct 28, 2018 6:51 pm
- Forum: Ionic & Covalent Bonds
- Topic: Polyatomic Ions [ENDORSED]
- Replies: 4
- Views: 500
Re: Polyatomic Ions [ENDORSED]
Even if we aren't supposed to specifically memorize a list, I do think it is always good to memorize the big name ones (such as Nitrate, Carbonate, etc) since you might need them in the future for other chemistry related classes.
- Sun Oct 21, 2018 11:22 pm
- Forum: DeBroglie Equation
- Topic: Rest Mass
- Replies: 7
- Views: 670
Re: Rest Mass
A good rule of thumb is that problems with DeBroglie's equation are almost always large objects such as baseballs or cars. Those are able to be stopped (have no momentum) and therefore have a rest mass.
- Sun Oct 21, 2018 11:20 pm
- Forum: Einstein Equation
- Topic: The symbol v?
- Replies: 16
- Views: 8604
Re: The symbol v?
As everyone has said before. The letter v represents velocity while the curvy v represents frequency. The two are almost never in the same equation, and if you are doubtful about which one you are to use, try to cancel out the units to see if they match what you need to find. Velocity is almost alwa...
- Sun Oct 21, 2018 11:17 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals on the test
- Replies: 6
- Views: 516
Re: Orbitals on the test
On the course website, Lavelle states that Test 2 will cover up to quantum numbers. So basically, how to name an electron in an atom.
- Sun Oct 14, 2018 9:06 pm
- Forum: Properties of Light
- Topic: Speed of Light
- Replies: 41
- Views: 2699
Re: Speed of Light
The speed of light is a constant, therefore it will never change. You can, however, convert it to other units if you wish, as long as all the correct units cancel out.
- Sun Oct 14, 2018 9:01 pm
- Forum: Properties of Light
- Topic: Colors and Frequency
- Replies: 14
- Views: 1557
Re: Colors and Frequency
I think it's good to have a general knowledge of where each colors are and their corresponding wavelengths and frequencies. From how I remember it, from decreasing wavelength, the order goes Red, Orange, Yellow, Green, Blue, and Violet. This corresponds to increasing frequencies. I use the acronym R...
- Sun Oct 14, 2018 8:55 pm
- Forum: Properties of Electrons
- Topic: Diffraction patterns
- Replies: 9
- Views: 1063
Re: Diffraction patterns
Constructive and destructive interference are both diffraction patterns but they do the opposite of one another. Constructive occurs when two waves line up exactly (they overlap) and thus the resulting wave is a combination of the two original waves. Destructive is the opposite. Two waves overlap by...
- Sun Oct 07, 2018 6:27 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Molar Mass
- Replies: 8
- Views: 1272
Re: Molar Mass
Where do you find the mass of an atom on the periodic table? I agree with the above post. To find molar mass for a singular atom, you find the atom on the periodic table and look below it. For example, Hydrogen (H) would have an molar mass of 1.0079 while Oxygen (O) would have an molar mass of 16.0...
- Sun Oct 07, 2018 6:14 pm
- Forum: Significant Figures
- Topic: Decimal point
- Replies: 14
- Views: 830
Re: Decimal point
Can someone explain the difference in sig figs between 125 and 125. , if there is one? 125 and 125. both have 3 significant figures. However, 125.0 has 4 significant figures. The reason being that there is a 0 behind the decimal point in 125.0 while 125. does not have a 0. 125.00 would have 5 sig f...
- Sun Oct 07, 2018 6:10 pm
- Forum: SI Units, Unit Conversions
- Topic: mol vs. mmol
- Replies: 12
- Views: 2637
Re: mol vs. mmol
In an exam would we ever have to convert from mol to mmol or vice-versa? From what I've seen in my chemistry career so far (Chem Honors and AP Chemistry), I have never seen any question ask for the moles of a molecule/atom as mmol. It is almost always simply in moles. However, if you were to conver...