Search found 31 matches

by Connie Chen 3D
Sun Dec 09, 2018 10:49 pm
Forum: Sigma & Pi Bonds
Topic: Amount of sigma bonds
Replies: 6
Views: 109

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.
by Connie Chen 3D
Sun Dec 09, 2018 10:48 pm
Forum: Ionic & Covalent Bonds
Topic: boiling point
Replies: 3
Views: 57

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.
by Connie Chen 3D
Sun Dec 09, 2018 10:46 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizing power
Replies: 3
Views: 65

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.
by Connie Chen 3D
Sun Dec 09, 2018 10:44 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs.covalent bonding
Replies: 2
Views: 49

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.
by Connie Chen 3D
Mon Dec 03, 2018 11:33 pm
Forum: Trends in The Periodic Table
Topic: Atomic vs ionic radius
Replies: 4
Views: 51

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.
by Connie Chen 3D
Mon Dec 03, 2018 11:29 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Lone pair location
Replies: 3
Views: 49

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.
by Connie Chen 3D
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: 50

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 ...
by Connie Chen 3D
Sun Nov 25, 2018 9:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent/Angular Shape
Replies: 4
Views: 55

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.
by Connie Chen 3D
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: 48

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.
by Connie Chen 3D
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: 36

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.
by Connie Chen 3D
Mon Nov 19, 2018 10:06 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moments
Replies: 8
Views: 68

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...
by Connie Chen 3D
Mon Nov 19, 2018 10:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Cations vs anions
Replies: 3
Views: 71

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.
by Connie Chen 3D
Mon Nov 19, 2018 10:00 am
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pair influence on shape
Replies: 12
Views: 86

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...
by Connie Chen 3D
Sun Nov 11, 2018 2:46 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 4
Views: 59

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.
by Connie Chen 3D
Sun Nov 11, 2018 2:45 pm
Forum: Resonance Structures
Topic: Drawing resonance
Replies: 17
Views: 232

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.
by Connie Chen 3D
Sun Nov 11, 2018 2:41 pm
Forum: Lewis Structures
Topic: Formal charges
Replies: 15
Views: 141

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.
by Connie Chen 3D
Sun Nov 04, 2018 5:14 pm
Forum: Sigma & Pi Bonds
Topic: determining which bonds are in a molecule
Replies: 4
Views: 126

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.
by Connie Chen 3D
Sun Nov 04, 2018 5:10 pm
Forum: Properties of Light
Topic: Standard Units
Replies: 8
Views: 143

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.
by Connie Chen 3D
Sun Nov 04, 2018 5:07 pm
Forum: Properties of Light
Topic: Photoelectric Effect - waves vs. photons
Replies: 3
Views: 74

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...
by Connie Chen 3D
Sun Oct 28, 2018 5:59 pm
Forum: Dipole Moments
Topic: Intermolecular forces
Replies: 2
Views: 141

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...
by Connie Chen 3D
Sun Oct 28, 2018 5:56 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Bonds vs Covalent Bonds
Replies: 7
Views: 128

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...
by Connie Chen 3D
Sun Oct 28, 2018 5:51 pm
Forum: Ionic & Covalent Bonds
Topic: Polyatomic Ions [ENDORSED]
Replies: 4
Views: 85

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.
by Connie Chen 3D
Sun Oct 21, 2018 10:22 pm
Forum: DeBroglie Equation
Topic: Rest Mass
Replies: 7
Views: 149

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.
by Connie Chen 3D
Sun Oct 21, 2018 10:20 pm
Forum: Einstein Equation
Topic: The symbol v?
Replies: 16
Views: 234

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...
by Connie Chen 3D
Sun Oct 21, 2018 10:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals on the test
Replies: 6
Views: 100

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.
by Connie Chen 3D
Sun Oct 14, 2018 8:06 pm
Forum: Properties of Light
Topic: Speed of Light
Replies: 18
Views: 134

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.
by Connie Chen 3D
Sun Oct 14, 2018 8:01 pm
Forum: Properties of Light
Topic: Colors and Frequency
Replies: 13
Views: 164

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...
by Connie Chen 3D
Sun Oct 14, 2018 7:55 pm
Forum: Properties of Electrons
Topic: Diffraction patterns
Replies: 9
Views: 115

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...
by Connie Chen 3D
Sun Oct 07, 2018 5:27 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molar Mass
Replies: 8
Views: 284

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...
by Connie Chen 3D
Sun Oct 07, 2018 5:14 pm
Forum: Significant Figures
Topic: Decimal point
Replies: 14
Views: 203

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...
by Connie Chen 3D
Sun Oct 07, 2018 5:10 pm
Forum: SI Units, Unit Conversions
Topic: mol vs. mmol
Replies: 12
Views: 236

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...

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