Search found 32 matches

by Minsub Lee 3E
Fri Dec 07, 2018 2:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR in equal angles
Replies: 4
Views: 52

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...
by Minsub Lee 3E
Fri Dec 07, 2018 2:42 pm
Forum: Lewis Acids & Bases
Topic: Bronsted vs Lewis
Replies: 4
Views: 43

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.
by Minsub Lee 3E
Fri Dec 07, 2018 2:36 pm
Forum: Conjugate Acids & Bases
Topic: Water as an Acid/Base
Replies: 8
Views: 60

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.
by Minsub Lee 3E
Fri Dec 07, 2018 2:27 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: calculating pH
Replies: 1
Views: 34

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.
by Minsub Lee 3E
Sun Dec 02, 2018 7:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 12
Views: 146

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.
by Minsub Lee 3E
Sun Dec 02, 2018 7:27 pm
Forum: Lewis Acids & Bases
Topic: Weak Acid/Base vs. Strong
Replies: 7
Views: 110

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.
by Minsub Lee 3E
Sun Dec 02, 2018 7:21 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Soapy Feels
Replies: 3
Views: 55

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.
by Minsub Lee 3E
Sun Nov 25, 2018 11:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming Shapes
Replies: 5
Views: 46

Re: Naming Shapes

For sake of saving time of future exams, I would say that it is best to memorize the shapes.
by Minsub Lee 3E
Sun Nov 25, 2018 11:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model
Replies: 4
Views: 39

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.
by Minsub Lee 3E
Sun Nov 25, 2018 11:33 pm
Forum: Electronegativity
Topic: The central atom
Replies: 3
Views: 76

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...
by Minsub Lee 3E
Thu Nov 15, 2018 2:04 am
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle
Replies: 4
Views: 65

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.
by Minsub Lee 3E
Thu Nov 15, 2018 2:02 am
Forum: Bond Lengths & Energies
Topic: Strength of Bonds
Replies: 9
Views: 153

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
by Minsub Lee 3E
Thu Nov 15, 2018 1:54 am
Forum: Determining Molecular Shape (VSEPR)
Topic: See-Saw Shape
Replies: 3
Views: 76

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.
by Minsub Lee 3E
Thu Nov 15, 2018 1:51 am
Forum: Student Social/Study Group
Topic: midterm average
Replies: 4
Views: 161

Re: midterm average

I believe the average was an 83%.
by Minsub Lee 3E
Mon Nov 12, 2018 12:36 am
Forum: Electronegativity
Topic: Electronegativity Graph
Replies: 4
Views: 103

Re: Electronegativity Graph

Thank you! This electronegativity graph is very useful!
by Minsub Lee 3E
Mon Nov 12, 2018 12:35 am
Forum: Bond Lengths & Energies
Topic: Bond lengths [ENDORSED]
Replies: 3
Views: 74

Re: Bond lengths [ENDORSED]

A single bond between two atoms is the longest and weakest while a triple bond is the shortest and strongest.
by Minsub Lee 3E
Mon Nov 12, 2018 12:32 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR
Replies: 3
Views: 47

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.
by Minsub Lee 3E
Mon Nov 05, 2018 3:16 pm
Forum: Octet Exceptions
Topic: Octet exceptions
Replies: 8
Views: 155

Re: Octet exceptions

They can have expanded valence shells because they have d-orbitals to accommodate additional electrons.
by Minsub Lee 3E
Fri Nov 02, 2018 2:44 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: f- orbital
Replies: 3
Views: 84

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
by Minsub Lee 3E
Fri Nov 02, 2018 2:42 pm
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 4564

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.
by Minsub Lee 3E
Fri Nov 02, 2018 2:34 pm
Forum: Administrative Questions and Class Announcements
Topic: Cheat sheet or open notes? [ENDORSED]
Replies: 2
Views: 87

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.
by Minsub Lee 3E
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: 63

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.
by Minsub Lee 3E
Thu Oct 25, 2018 2:57 am
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 96
Views: 29379

Re: Advice from a Medical Student [ENDORSED]

Thank you so much! Transitioning into college has been tough, but this was very encouraging!
by Minsub Lee 3E
Fri Oct 19, 2018 1:38 pm
Forum: Properties of Electrons
Topic: Nodal Plane
Replies: 5
Views: 122

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.
by Minsub Lee 3E
Fri Oct 19, 2018 1:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 3
Views: 81

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.
by Minsub Lee 3E
Fri Oct 19, 2018 1:11 pm
Forum: Properties of Light
Topic: Friday 10/5 Lecture
Replies: 7
Views: 80

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
by Minsub Lee 3E
Thu Oct 11, 2018 4:08 pm
Forum: Einstein Equation
Topic: Units
Replies: 5
Views: 85

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...
by Minsub Lee 3E
Thu Oct 11, 2018 4:04 pm
Forum: Properties of Light
Topic: Problem 1A.9 (7th edition)
Replies: 5
Views: 37

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.
by Minsub Lee 3E
Thu Oct 11, 2018 3:58 pm
Forum: Molarity, Solutions, Dilutions
Topic: Actual/Theoretical Yield
Replies: 7
Views: 425

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...
by Minsub Lee 3E
Thu Oct 04, 2018 1:59 am
Forum: Balancing Chemical Reactions
Topic: Balancing reactions tips
Replies: 29
Views: 608

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.
by Minsub Lee 3E
Thu Oct 04, 2018 1:56 am
Forum: Limiting Reactant Calculations
Topic: Combustion Analysis? [ENDORSED]
Replies: 7
Views: 123

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.
by Minsub Lee 3E
Thu Oct 04, 2018 1:49 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Problem E7 converting atoms to moles
Replies: 4
Views: 45

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.

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