Search found 27 matches

by Gwen Casillan 3E
Sun Jan 17, 2021 8:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #9
Replies: 4
Views: 22

Re: Sapling Week 1 #9

So first, find K and set up an ICE table. K is found from [NO]^2/[N2][O2], so it would be [0.400]^2/[0.300][0.300] = 16/9 Products [NO] are added, so reaction shifts toward reactants. Setting up an ICE table you get: [N2]=[O2]=(0.300 + x) and [NO]=(0.700-2x) *keep in mind that change in NO is -2x be...
by Gwen Casillan 3E
Sun Jan 17, 2021 8:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #9
Replies: 11
Views: 70

Re: Sapling Week 1 #9

The change in x would be +x for both N2 and O2, while for 2NO the change in x would be -2x. This is because adding 2NO to the reaction at equilibrium causes the reaction to shift towards the reactants according to Le Chatelier's Principle. The molar coefficients for N2 and O2 are both 1 so the chang...
by Gwen Casillan 3E
Sun Jan 17, 2021 8:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE table equilibrium
Replies: 8
Views: 18

Re: ICE table equilibrium

Basically, you want to look at what exactly is changing/being added to the reaction in order to figure out the change in molarity. The change will not always be positive for products and negative for reactants. Looking at a reaction one would generally ask, does the reaction move towards making more...
by Gwen Casillan 3E
Sun Jan 17, 2021 7:55 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 46
Views: 156

Re: Q and K

Yes, Q is the reaction quotient, and K is the equilibrium constant. Q indicates that there is a shift, while K indicates equilibrium. We use Q and compare it to K to see whether the reaction is at equilibrium (Q=K), favors reactants (Q>K), or favors products (Q<K).
by Gwen Casillan 3E
Sun Jan 17, 2021 7:51 pm
Forum: Student Social/Study Group
Topic: Comfort Movies
Replies: 117
Views: 260

Re: Comfort Movies

I definitely love watching Pride and Prejudice, Your Name, and Howl's Moving Castle. I love romances and any Ghibli films are always a good watch for feelings of nostalgia and comfort.
by Gwen Casillan 3E
Sun Jan 17, 2021 7:47 pm
Forum: Ideal Gases
Topic: reversing reactions
Replies: 83
Views: 396

Re: reversing reactions

It would be the inverse of K, so 1/K.
by Gwen Casillan 3E
Sun Jan 17, 2021 7:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Homework #5
Replies: 9
Views: 56

Re: Sapling Homework #5

When combining equations, keep in mind that the K value of a reverse reaction will be the inverse of the original K value: (1/K), while the K value of a reaction that has a coefficient (c) will be the original reaction's K value raised to the power of the coefficient: K^c. Then, once the new K value...
by Gwen Casillan 3E
Sun Jan 10, 2021 11:46 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 179
Views: 106778

Re: Reading the textbook [ENDORSED]

The textbook can definitely be helpful supplemental material to support learning. I generally us it to reaffirm knowledge of concepts and getting more practice and comfortable with problems.
by Gwen Casillan 3E
Sun Jan 10, 2021 11:40 pm
Forum: Student Social/Study Group
Topic: Study Tips
Replies: 30
Views: 75

Re: Study Tips

Definitely doing practice problems help, as well as making sure one understands a concept and is comfortable enough to solve problems before moving on.
by Gwen Casillan 3E
Sun Jan 10, 2021 11:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs. Q
Replies: 53
Views: 163

Re: K vs. Q

Devan Nathu - 2H wrote:Just to clarify, will we always be able to assume that the reaction is at equilibrium when K=Q? Thanks!!


Yes, since K is the equilibrium constant, when Q (the reaction quotient) is equal to K, the reaction is at equilibrium.
by Gwen Casillan 3E
Sun Jan 10, 2021 11:24 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8528
Views: 1473766

Re: Post All Chemistry Jokes Here

I really enjoy chemistry jokes, periodically, that is.
by Gwen Casillan 3E
Sun Jan 10, 2021 11:06 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student - Part II [ENDORSED]
Replies: 209
Views: 15672

Re: Advice from a Medical Student - Part II [ENDORSED]

This is really inspiring to read about, and I am so grateful to be able to read your advice and experiences.
by Gwen Casillan 3E
Sun Jan 10, 2021 10:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Posts in 14B [ENDORSED]
Replies: 115
Views: 1815

Re: Chemistry Posts in 14B [ENDORSED]

I believe the accounts remain the same and the new posts are added to the old account.
by Gwen Casillan 3E
Sat Dec 07, 2019 11:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear VSEPR model
Replies: 21
Views: 552

Re: Linear VSEPR model

So if the central atom has lone pairs in addition to the bods, then the molecular shape will be bent due to the additional repulsion that the lone pairs have on the other atoms/bonded pair electrons.
by Gwen Casillan 3E
Sat Dec 07, 2019 11:34 pm
Forum: Naming
Topic: charges on a compound
Replies: 2
Views: 36

Re: charges on a compound

So you’d find the charge on the cation by calculating the charge of the anion and figuring out what the charge should be on the cation to get the total charge of the ligand. In this case the total charge is 2-, and CN has a -1 charge (and there are 5 CN- anions, adding up to a -5 charge). Therefore,...
by Gwen Casillan 3E
Sat Dec 07, 2019 11:24 pm
Forum: Naming
Topic: bis,tris,tetrakis
Replies: 6
Views: 186

Re: bis,tris,tetrakis

They are prefixes used for naming ligand when the name for a ligand already includes di- (for example, one wouldn’t say di-di-ethylene, but rather bis-diethylene), tri-, or tetra-, and also when a ligand is polydentate (like en/ethylenediamine).
by Gwen Casillan 3E
Sat Dec 07, 2019 11:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 16
Views: 259

Re: bond angles

Bond angles were covered in lecture and can also be found in the textbook. Bond angles are affected by repulsion between electrons, with stronger repulsions between lone pair and lone pair electrons and weaker repulsions between bonded pair and bonded pair electrons.
by Gwen Casillan 3E
Fri Nov 15, 2019 12:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair Repulsion?
Replies: 5
Views: 101

Re: Lone Pair Repulsion?

Lone pair electrons are further from the positively-charged nucleus of an atom compared to bonding pairs of electrons and are therefore bound with less electrostatic force, causing them to have stronger repulsive forces than bonding pairs of electrons. Lone pairs have a larger range of negativity co...
by Gwen Casillan 3E
Fri Nov 15, 2019 12:00 pm
Forum: Dipole Moments
Topic: 3 Hydrocarbon Example?
Replies: 1
Views: 53

Re: 3 Hydrocarbon Example?

The 3 hydrocarbons at room temperature show that the greater amount of atoms there are, the stronger dispersion forces are, increasing the attractive forces between them, explaining why octadecane (C 18 H 38 ) is closer to a waxy solid than pentane (C 5 H 12 ), which is a mobile fluid, even though t...
by Gwen Casillan 3E
Fri Nov 15, 2019 11:51 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis structure for 2E23 (a)
Replies: 1
Views: 28

Re: Lewis structure for 2E23 (a)

Yes, I believe there should be a double bond, but as VSEPR primarily looks at electron densities and the position of atoms, the lewis structure depicting the single bond between Sb and O allows one to predict the shape by primarily looking at bonded pairs of electrons and lone pairs of electrons.
by Gwen Casillan 3E
Fri Nov 15, 2019 11:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Inter-molecular Electron Repulsion
Replies: 6
Views: 48

Re: Inter-molecular Electron Repulsion

The repulsion forces in order of least to most strong are:
bonding-bonding pr < lone-bonding pr < lone-lone pr
by Gwen Casillan 3E
Fri Oct 04, 2019 12:36 pm
Forum: Significant Figures
Topic: Significant Figures
Replies: 6
Views: 117

Re: Significant Figures

It's best to apply significant figures at the end in order to retain as much accuracy as possible. Rounding early on or in the middle of calculations may initially seem convenient and more practical, but the dropping of a few decimal places/numbers can be severely detrimental to the final result, as...
by Gwen Casillan 3E
Fri Oct 04, 2019 12:26 pm
Forum: Limiting Reactant Calculations
Topic: General Limiting Reactant Question
Replies: 4
Views: 79

Re: General Limiting Reactant Question

There was only one reactant for M.3 and therefore, you did not need to find a limiting reactant/there was none. If there is more than one reactant, you would use the given moles/masses and molar masses to determine the limiting reactant and use that information to calculate the theoretical yield.
by Gwen Casillan 3E
Fri Oct 04, 2019 12:18 pm
Forum: Limiting Reactant Calculations
Topic: M5
Replies: 2
Views: 64

Re: M5

Just use the stoichiometric steps you used to calculate the the 12 mols of the ClO2F product to determine the moles of the other product (Br2).
by Gwen Casillan 3E
Fri Oct 04, 2019 11:56 am
Forum: Empirical & Molecular Formulas
Topic: E.11
Replies: 1
Views: 46

Re: E.11

Yes, you would need to consider the different masses of the isotopes because they have different percentages of abundance, both of which you would then use to calculate the mass of the average lithium atom by adding them together: (7.42/100)(9.988 * 10^-24 g) + (92.58/100)(1.165 * 10^-24 g) = the av...
by Gwen Casillan 3E
Fri Oct 04, 2019 11:38 am
Forum: Molarity, Solutions, Dilutions
Topic: Dilution Calculation
Replies: 5
Views: 88

Re: Dilution Calculation

Yes, you could technically leave the volume in mL since the molarity would cancel, but remember to keep in mind that otherwise, it would be wiser to leave it in liters.

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