Search found 50 matches

by Michelle Lu 1F
Sun Mar 18, 2018 2:37 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

I told my friends a chemistry joke today.
There was no reaction.
by Michelle Lu 1F
Sun Mar 18, 2018 2:34 am
Forum: General Rate Laws
Topic: 15.85 Drawing structures for activated complex
Replies: 3
Views: 342

Re: 15.85 Drawing structures for activated complex

The activated complex is basically the transition state which is the state at which bonds are being both broken and formed. In order to draw the activated complex, you would draw the molecule with its changing bonds, inserting dotted lines where new bonds are forming and where bonds are breaking to ...
by Michelle Lu 1F
Sun Mar 18, 2018 2:32 am
Forum: *Identifying Primary, Secondary, Tertiary, Quaternary Carbons, Hydrogens, Nitrogens
Topic: Functional Groups
Replies: 1
Views: 192

Re: Functional Groups

Yes, I think we mainly just need to be able to identify the functional groups we went over in lecture. I highly doubt we would have to know how to draw molecules although I would know the overall structure of each functional group.
by Michelle Lu 1F
Sun Mar 18, 2018 2:26 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

What did the scientist say when he discovered two isotopes of Helium?
HeHe.
by Michelle Lu 1F
Sun Mar 18, 2018 2:26 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

Why does a hamburger have lower energy than a steak?
Because it's in the ground state.
by Michelle Lu 1F
Sun Mar 18, 2018 2:25 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

Did you know you can cool yourself to -273.15 ºC and be 0K?
by Michelle Lu 1F
Sun Mar 18, 2018 2:23 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

I'd tell you a chemistry joke, but all the good ones argon.
by Michelle Lu 1F
Sun Mar 18, 2018 2:22 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

What is the chemical formula for a banana? BaNa2
by Michelle Lu 1F
Fri Mar 16, 2018 8:23 pm
Forum: *Nucleophiles
Topic: Functional Groups
Replies: 3
Views: 211

Re: Functional Groups

You just need to be able to identify the 6 different functional groups gone over lecture, including alcohol, ethers, ketones, aldehydes, carboxylic acids, and amines. He will most likely give you a visual representation of the overall structure and you will have to identify which functional group(s)...
by Michelle Lu 1F
Thu Mar 15, 2018 10:32 am
Forum: Second Order Reactions
Topic: Half-Life of a Second Order Reaction
Replies: 3
Views: 210

Re: Half-Life of a Second Order Reaction

No problem, anytime!!
by Michelle Lu 1F
Thu Mar 15, 2018 10:28 am
Forum: Second Order Reactions
Topic: Half-Life of a Second Order Reaction
Replies: 3
Views: 210

Re: Half-Life of a Second Order Reaction

Hello! The relationship between rate and concentration are completely different for the half lives of 1st and 2nd order reactions. While for 1st order reactions the half life stays constant for all concentrations, for 2nd order reactions, the half life increases as concentration decreases and decay ...
by Michelle Lu 1F
Tue Mar 13, 2018 5:07 pm
Forum: General Rate Laws
Topic: graphs
Replies: 8
Views: 193

Re: graphs

I would suggest knowing at least which graphs for a reaction can help you determine which order a reaction may be. There could easily be a question giving you three graphs in which you have to figure out visually which graph is the most linear and therefore determine the reaction order.
by Michelle Lu 1F
Tue Mar 13, 2018 5:04 pm
Forum: First Order Reactions
Topic: 15.23C
Replies: 6
Views: 262

Re: 15.23C

You cannot determine the order of a reaction by looking at the coefficients of the reactants or products. However, you can use these coefficients to determine the ratios of the rates for the consumption of reactants or the production of products.
by Michelle Lu 1F
Tue Mar 13, 2018 5:02 pm
Forum: First Order Reactions
Topic: Slope of 1st order RXNs
Replies: 9
Views: 324

Re: Slope of 1st order RXNs

If the graph of time plotted against ln[A] is linear, then this indicates that the reaction with respect to reactant A is 1st order. The integrated rate law for 1st order reactions is ln[A] = -kt + ln[Ao]. If you look at this equation as if it is in the form of y = mx + b, you can see that the slope...
by Michelle Lu 1F
Tue Mar 13, 2018 4:58 pm
Forum: First Order Reactions
Topic: 15.37C
Replies: 5
Views: 338

Re: 15.37C

In this particular situation, the volumes end up cancelling out, so if you were able to recognize this was going to occur, then you could have left it out of the picture. However, common safe practice involves solving for the concentration using the mass given and the volume 2500. L, and this could ...
by Michelle Lu 1F
Tue Mar 13, 2018 4:54 pm
Forum: First Order Reactions
Topic: Reaction Order [ENDORSED]
Replies: 6
Views: 296

Re: Reaction Order [ENDORSED]

Reaction orders, along with the rate constant (k), can only be obtained experimentally. This would mean plotting points with respect to each reactant in graphs comparing [A], ln[A], and 1/[A] to time, and observing which graph is the most linear for that respective reactant. Then, to find the overal...
by Michelle Lu 1F
Tue Mar 13, 2018 4:48 pm
Forum: General Rate Laws
Topic: Distinguishing Different Types of Constants
Replies: 3
Views: 117

Re: Distinguishing Different Types of Constants

Hello, yes the k constant used for the forward reaction is the rate constant used in the forward reaction rate law. The way to differentiate this rate constant from k', the reverse rate constant, is the apostrophe. K on the other hand is the capital letter, which indicates that it is referring to th...
by Michelle Lu 1F
Tue Mar 13, 2018 4:39 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

I wish I was adenine so I could get paired with U.
by Michelle Lu 1F
Tue Mar 13, 2018 4:36 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

Girl you must be made of Florine, Iodine, and Neon, because you are FINe
by Michelle Lu 1F
Tue Mar 13, 2018 4:35 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

.
by Michelle Lu 1F
Tue Mar 13, 2018 4:32 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

.
by Michelle Lu 1F
Tue Mar 13, 2018 4:29 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

Why do white bears like the water so much? Because they're polar.
by Michelle Lu 1F
Tue Mar 13, 2018 4:29 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 788498

Re: Post All Chemistry Jokes Here

Why do chemists like nitrates so much? Because they are cheaper than day rates.
by Michelle Lu 1F
Tue Feb 20, 2018 11:53 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.37 C
Replies: 2
Views: 89

14.37 C

Why is the 2H+ + 2e- => H2 the reduction reaction? The standard reduction potential for that reaction is 0, whereas the the standard reduction potential for the other reaction 2Cl- => Cl2 + 2e- is +1.36, which is greater and therefore has stronger oxidizing power and should be the reduction reaction?
by Michelle Lu 1F
Tue Feb 20, 2018 11:34 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13B
Replies: 3
Views: 122

Re: 14.13B

Would a liquid metal work as an electrode as well? For example, Hg(l)?
by Michelle Lu 1F
Tue Feb 20, 2018 10:04 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.15 B
Replies: 1
Views: 78

14.15 B

In textbook question 14.15 part B, how do we know to incorporate O2 into the half-reactions for both reduction and oxidation? Or is this just something specific to neutralization that we must know?
by Michelle Lu 1F
Tue Feb 20, 2018 10:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.13B
Replies: 3
Views: 122

14.13B

For question 14.13 part B, I understand why we must use Pt as an electrode for the Ce3+ and Ce4+ side, however, why can't we use I2(s) as an electrode for the other side? It is in solid state and is involved in the redox reaction.
by Michelle Lu 1F
Sun Jan 14, 2018 1:33 am
Forum: Phase Changes & Related Calculations
Topic: Why can state properties be added?
Replies: 11
Views: 363

Re: Why can state properties be added?

These state properties are independent of the path taken to transform into their state, allowing these set values to be both added and subtracted.
by Michelle Lu 1F
Sun Jan 14, 2018 1:30 am
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 13
Views: 451

Re: Phase Changes

Exothermic reactions release heat, and therefore the product will be colder. This means that the exothermic phase changes are going down the heat curve, including freezing, condensation, and deposition.
by Michelle Lu 1F
Sun Jan 14, 2018 1:24 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Sublimation
Replies: 4
Views: 191

Re: Sublimation

Sublimation by definition is the physical transition between the phases solid and vapor. This is a direct change between these two phases without going through the liquid phase. Dry ice at normal room temperature is a common example of sublimation.
by Michelle Lu 1F
Sun Dec 10, 2017 9:10 pm
Forum: Amphoteric Compounds
Topic: Amphoteric compounds
Replies: 3
Views: 466

Re: Amphoteric compounds

There are certain atoms, including Al, Ga, In, Ge, Sn, Pb, As, Sb, and Bi, which can form amphoteric oxides with oxygen.
by Michelle Lu 1F
Sun Dec 10, 2017 9:05 pm
Forum: Naming
Topic: Cis vs trans
Replies: 3
Views: 252

Re: Cis vs trans

Cis- vs. trans- are prefixes that indicate the position of ligands. Cis- occurs when both ligands are on the same side and therefore cause the molecule to be polar. Trans- is when ligands are on opposite sides and cancel each other's charges out, leaving the molecule as nonpolar.
by Michelle Lu 1F
Sun Dec 03, 2017 9:30 pm
Forum: Naming
Topic: Naming
Replies: 4
Views: 189

Re: Naming

You use "bis-", "tris-" etc when the ligand already has a prefix such as "di-" or "tri-"
by Michelle Lu 1F
Sun Dec 03, 2017 9:27 pm
Forum: Naming
Topic: Naming Coordination Compounds
Replies: 8
Views: 275

Re: Naming Coordination Compounds

The suffix "-ate" is added to the end of the ion when the ion has a negative charge, and it is not added when the ion has a positive charge.
by Michelle Lu 1F
Sun Nov 26, 2017 8:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs vs. Bonding Pairs
Replies: 6
Views: 284

Re: Lone Pairs vs. Bonding Pairs

This is because bonded electrons are bound to a certain region of the sigma bond, whereas lone pairs are much more free to move and have more space since they aren't involved in any bonds that restrict their movement.
by Michelle Lu 1F
Sun Nov 26, 2017 8:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw molecular shape
Replies: 4
Views: 399

Re: Seesaw molecular shape

If the central atom of a molecule has 4 bonded electron pairs and 1 lone pair, this will cause the molecule to have the seesaw shape.
by Michelle Lu 1F
Sun Nov 19, 2017 11:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 4
Views: 171

Re: Lone Pairs

Yes lone pairs can change bond angles and cause. molecule to be bent. however pairs that are opposite of each other can cancel each other's charges out and not affect the bond angle at all.
by Michelle Lu 1F
Sun Nov 19, 2017 9:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent or linear?
Replies: 11
Views: 551

Re: Bent or linear?

If there are no lone pairs on the central atom, then the shape of the molecule will be linear. However, if there are lone pairs on the central atom, the electron repulsion that they will create with the other bonds connecting the central atom will cause the shape to be bent.
by Michelle Lu 1F
Sat Nov 11, 2017 3:44 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Isoelectronic [ENDORSED]
Replies: 4
Views: 239

Re: Isoelectronic [ENDORSED]

No, Be2+ and Li+ would actually be isoelectronic to He since Be would be losing 2 and Li would be losing 1 electron. In order to be isoelectronic, Be2+, Li+, and Ne would have to have the same number of electrons. For example, Na+ and Mg2+ would be isoelectronic to Ne.
by Michelle Lu 1F
Sat Nov 11, 2017 3:10 pm
Forum: Lewis Structures
Topic: HOCO [ENDORSED]
Replies: 3
Views: 210

Re: HOCO [ENDORSED]

Yes, I agree with the above reply. I also did the same thing. If you are wondering why the unpaired electron would go on the Carbon, there are two main reasons. One is that by giving Oxygen two bonded pairs and two unbonded pairs, both Oxygens get a FC of zero, which is ideal. Second, Carbon is less...
by Michelle Lu 1F
Sun Nov 05, 2017 7:22 pm
Forum: Resonance Structures
Topic: Delocalized
Replies: 7
Views: 352

Re: Delocalized

Since the actual structure of the molecule is an average of its possible resonance structures, this means that the electrons are not involved in just one bond, but shared among multiple bonds throughout the same molecule.
by Michelle Lu 1F
Sun Nov 05, 2017 7:20 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 3
Views: 232

Re: Resonance Structures

In order to determine the number of resonance structures there are of a certain molecule, you must draw out all of the possible structures whether it's using single, double, or triple bonds. However, you must make sure that these have the correct number of valence electrons, otherwise it is not a re...
by Michelle Lu 1F
Sun Oct 29, 2017 11:10 pm
Forum: Properties of Light
Topic: Velocity [ENDORSED]
Replies: 13
Views: 612

Re: Velocity [ENDORSED]

Speed is basically the absolute value of velocity, because velocity is speed but with direction. They both have the same units m/s.
by Michelle Lu 1F
Sun Oct 29, 2017 11:09 pm
Forum: Properties of Light
Topic: The uncertainty principle [ENDORSED]
Replies: 5
Views: 373

Re: The uncertainty principle [ENDORSED]

At the subatomic level, particles are influenced in a different manner than with classical mechanics. For example, at this small scale, photons would interfere with the electrons, whereas a much larger object such as a cup would not be affected by a photon at all.
by Michelle Lu 1F
Sun Oct 22, 2017 4:26 pm
Forum: Photoelectric Effect
Topic: Number of Photons
Replies: 4
Views: 219

Re: Number of Photons

An increase in intensity correlates with an increase in the number of photons. During the experiment, the reason why increasing the intensity didn't eject an electron explains why light has particle-like properties. Since photons each interact with only one electron each, even though there are many ...
by Michelle Lu 1F
Sun Oct 22, 2017 4:14 pm
Forum: Photoelectric Effect
Topic: Energy of Photon [ENDORSED]
Replies: 9
Views: 436

Re: Energy of Photon [ENDORSED]

I know that the energy of a photon has to be greater than the energy to remove an electron in order for light to be absorbed, but what happens when the energies are equal to each other? Is there a difference in outcome or in the values of the velocity of the electron? Yes, when the energy of the inc...
by Michelle Lu 1F
Sun Oct 15, 2017 11:59 pm
Forum: Properties of Light
Topic: Formulas [ENDORSED]
Replies: 5
Views: 240

Re: Formulas [ENDORSED]

They can both be derived from one another depending on whether you would like to solve for En or v, using the equation E=-hR/n^2.
by Michelle Lu 1F
Sun Oct 15, 2017 11:58 pm
Forum: Properties of Light
Topic: Planck's Constant
Replies: 10
Views: 425

Re: Planck's Constant

Plank's constant is used in a variety of common equations such as E = (hv)/λ and λ=h/p and it was a constant that was found experimentally.
by Michelle Lu 1F
Thu Oct 05, 2017 8:54 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical equations too slow... any advice? [ENDORSED]
Replies: 18
Views: 1371

Re: Balancing Chemical equations too slow... any advice? [ENDORSED]

For me, it personally helps to first balance the element that occurs in the least number of molecules of the chemical equation. This is because if an element in part of multiple molecules, it is much harder to balance those in the beginning since you will have to most likely change the stoichiometri...
by Michelle Lu 1F
Thu Oct 05, 2017 8:04 pm
Forum: Balancing Chemical Reactions
Topic: Combustion [ENDORSED]
Replies: 6
Views: 397

Re: Combustion [ENDORSED]

Yes that is a combustion reaction! What a combustion reaction consists of is some form of a hydrocarbon reacting with gaseous O2 to result in water and carbon dioxide, and the equation you posted above matches this definition. You do need both carbon and hydrogen among the reactants (hydrocarbon and...

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