Search found 32 matches
- Fri Dec 07, 2018 2:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR in equal angles
- Replies: 4
- Views: 785
Re: VSEPR in equal angles
Yes, like what most people said, the molecule is nonpolar unless the bonded atoms are not uniform. An example of this is CH4 and CClH3. Although both molecules have a tetrahedral molecular shape, CClH3 is polar because the partial charge given by the electronegativity difference of the chlorine atom...
- Fri Dec 07, 2018 2:42 pm
- Forum: Lewis Acids & Bases
- Topic: Bronsted vs Lewis
- Replies: 4
- Views: 402
Re: Bronsted vs Lewis
Yes, it is the other way. Every Bronsted Acid fits the definition of a Lewis acid, but is not true for the reverse.
- Fri Dec 07, 2018 2:36 pm
- Forum: Conjugate Acids & Bases
- Topic: Water as an Acid/Base
- Replies: 20
- Views: 1573
Re: Water as an Acid/Base
Water can both act as an acid or base depending on the chemical reaction. When reacting with HCl, it acts as a base because it is accepting the H+ from HCl to form H3O+. However, when reacting with NH3, it acts as an acid because it is donating a proton to NH3 to form NH4.
- Fri Dec 07, 2018 2:27 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: calculating pH
- Replies: 1
- Views: 277
Re: calculating pH
Use sig figs according to the concentration value. If the concentration of H+ is 3.2, then the answer should be in 2 sig figs.
- Sun Dec 02, 2018 7:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 12
- Views: 1195
Re: Bond Angles
@joanneyseung22 If there are lone pairs on the central atom, it will want to take up more space. Therefore, the bonded atoms will be condensed away from the lone pairs. Therefore, the bond angle will be slightly less than the standard bond angles of the molecular shape.
- Sun Dec 02, 2018 7:27 pm
- Forum: Lewis Acids & Bases
- Topic: Weak Acid/Base vs. Strong
- Replies: 7
- Views: 904
Re: Weak Acid/Base vs. Strong
For this class, a good way to differentiate between strong acids/bases from weak acids/bases is by memorizing the strong ones. Only a few acids and bases are strong. If you do not recognize the acid as a strong acid, it is most likely a weak acid.
- Sun Dec 02, 2018 7:21 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Soapy Feels
- Replies: 4
- Views: 794
Re: Soapy Feels
Bases react with cells in skin, dissolving the fatty acids and oils from your skin; therefore, it decreases the friction between fingers when rubbing together.
- Sun Nov 25, 2018 11:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Naming Shapes
- Replies: 5
- Views: 520
Re: Naming Shapes
For sake of saving time of future exams, I would say that it is best to memorize the shapes.
- Sun Nov 25, 2018 11:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR model
- Replies: 4
- Views: 427
Re: VSEPR model
'A' refers to the central atom, 'X' refers to the bonded atom, and 'E' refers to lone pair. By knowing how much of each are there, you can determine how many atoms and lone pairs there are, and then determine the shape of the molecule.
- Sun Nov 25, 2018 11:33 pm
- Forum: Electronegativity
- Topic: The central atom
- Replies: 3
- Views: 717
Re: The central atom
Both ionization energy and electronegativity increases as you move up and right of the periodic table. Electronegativity decreases as you go down the group because the increasing number of energy levels cause the outer electrons to be further away from the nucleus. Ionization energy increases as you...
- Thu Nov 15, 2018 2:04 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: bond angle
- Replies: 4
- Views: 439
Re: bond angle
The double and triple bonds will not necessarily directly affect the bond angle. However, those bonds will most likely affect the molecular shape, which will affect the bond angles.
- Thu Nov 15, 2018 2:02 am
- Forum: Bond Lengths & Energies
- Topic: Strength of Bonds
- Replies: 9
- Views: 1083
Re: Strength of Bonds
For now, I do not think we need to. However, you should at least conceptually know that triple bonds are stronger and shorter than single bonds
- Thu Nov 15, 2018 1:54 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: See-Saw Shape
- Replies: 3
- Views: 514
Re: See-Saw Shape
Going off of Melissa, the lone pair on the central atom wants to occupy as much space as they can, so they push the other atoms in the opposite direction, condensing the atoms to each other to make a see saw structure.
- Thu Nov 15, 2018 1:51 am
- Forum: Student Social/Study Group
- Topic: midterm average
- Replies: 4
- Views: 544
Re: midterm average
I believe the average was an 83%.
- Mon Nov 12, 2018 12:36 am
- Forum: Electronegativity
- Topic: Electronegativity Graph
- Replies: 4
- Views: 474
Re: Electronegativity Graph
Thank you! This electronegativity graph is very useful!
- Mon Nov 12, 2018 12:35 am
- Forum: Bond Lengths & Energies
- Topic: Bond lengths [ENDORSED]
- Replies: 3
- Views: 505
Re: Bond lengths [ENDORSED]
A single bond between two atoms is the longest and weakest while a triple bond is the shortest and strongest.
- Mon Nov 12, 2018 12:32 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR
- Replies: 3
- Views: 388
Re: VSEPR
By remembering the different shapes molecules can have, you can determine the shape by seeing the repulsion of the electrons and spreading the electrons as far apart as they can.
- Mon Nov 05, 2018 3:16 pm
- Forum: Octet Exceptions
- Topic: Octet exceptions
- Replies: 8
- Views: 1237
Re: Octet exceptions
They can have expanded valence shells because they have d-orbitals to accommodate additional electrons.
- Fri Nov 02, 2018 2:44 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: f- orbital
- Replies: 3
- Views: 499
Re: f- orbital
The last two rows of the periodic table consist of the f-orbitals. By looking at the atomic number of those elements, you can see that they fit in the middle of the periodic table. It is the row after Xe
- Fri Nov 02, 2018 2:42 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
- Replies: 121
- Views: 20129
Re: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
I got a molar mass of 30g/mol as well. I believe that the calculations are right.
- Fri Nov 02, 2018 2:34 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Cheat sheet or open notes? [ENDORSED]
- Replies: 2
- Views: 535
Re: Cheat sheet or open notes? [ENDORSED]
To my understanding, I believe the midterm is closed notes and are unable to access any outside information.
- Fri Nov 02, 2018 2:22 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Quantum Numbers related to Orbitals
- Replies: 4
- Views: 464
Re: Quantum Numbers related to Orbitals
One is not more correct than the other. I think it is enough to understand that no electrons of the same atom has the same quantum numbers, and that an upper arrow symbol indicates that it is positive 1/2. They are just different in that they are spinning clockwise versus counterclockwise.
- Thu Oct 25, 2018 2:57 am
- Forum: Administrative Questions and Class Announcements
- Topic: Advice from a Medical Student [ENDORSED]
- Replies: 297
- Views: 427773
Re: Advice from a Medical Student [ENDORSED]
Thank you so much! Transitioning into college has been tough, but this was very encouraging!
- Fri Oct 19, 2018 1:38 pm
- Forum: Properties of Electrons
- Topic: Nodal Plane
- Replies: 5
- Views: 904
Re: Nodal Plane
You can also think of nodal planes mathematically as when the wave function (psi) is equal to 0. So when you draw out an ideal sin graph for n=1, the wave function is not equal to 0, and so there are no nodal planes for the principal quantum number n=1.
- Fri Oct 19, 2018 1:26 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Nodal Planes
- Replies: 3
- Views: 497
Re: Nodal Planes
As others said, nodal planes are areas without electrons. Through diagrams, it also helps to determine what kind of electron you are observing and what its energy level is. For example, if there were zero nodal planes, then it would be a s-block element, and have a principal quantum number n=1.
- Fri Oct 19, 2018 1:11 pm
- Forum: Properties of Light
- Topic: Friday 10/5 Lecture
- Replies: 7
- Views: 676
Re: Friday 10/5 Lecture
Just a general tip is to remember the formulas and what you're trying to solve for. If you have to solve for kinetic energy, then you know you have to use velocity in the formula Kinetic Energy = 1/2mv^2
- Thu Oct 11, 2018 4:08 pm
- Forum: Einstein Equation
- Topic: Units
- Replies: 5
- Views: 1033
Re: Units
I like to write it out like in dimensional analysis. It will help you follow your work, and you can clearly see what can be cancelled out. Since 1 Hertz is 1/s, if you multiply it with Jxs, the s will be cancelled out, leaving just s. I suggest writing out the units in your work for dimensional anal...
- Thu Oct 11, 2018 4:04 pm
- Forum: Properties of Light
- Topic: Problem 1A.9 (7th edition)
- Replies: 5
- Views: 295
Re: Problem 1A.9 (7th edition)
Yes, use c=λv and e=hv to find the source. The correct unit for wavelength (λ) are meters.
- Thu Oct 11, 2018 3:58 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Actual/Theoretical Yield
- Replies: 8
- Views: 4303
Re: Actual/Theoretical Yield
Actual yield should typically not be greater than the theoretical yield because theoretical yield is the maximum amount of product that could have been produced. However, there may be cases in your own personal experiment which may result in a higher actual yield than the theoretical yield, resultin...
- Thu Oct 04, 2018 1:59 am
- Forum: Balancing Chemical Reactions
- Topic: Balancing reactions tips
- Replies: 29
- Views: 2161
Re: Balancing reactions tips
I will usually check to see which elements do not need balancing. Then I will start to balance the element that occurs the least. If adding a stoichiometric coefficient causes another element in that same molecule to be unbalanced, I would balance that. I usually just do that step-by-step.
- Thu Oct 04, 2018 1:56 am
- Forum: Limiting Reactant Calculations
- Topic: Combustion Analysis? [ENDORSED]
- Replies: 7
- Views: 445
Re: Combustion Analysis? [ENDORSED]
It will likely come up in the future. Dr. Lavelle mentioned that combustion, burning, or oxidation of organic molecules is the same as oxidative metabolism. They all release energy. This may be a key concept.
- Thu Oct 04, 2018 1:49 am
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Problem E7 converting atoms to moles
- Replies: 4
- Views: 372
Re: Problem E7 converting atoms to moles
Yes, you are able to submit questions from the sixth edition. On the syllabus, it will show the questions you need to answer for the sixth edition.