Search found 101 matches
- Sat Mar 13, 2021 11:17 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta U=0
- Replies: 17
- Views: 2651
Re: delta U=0
That's because there isn't any change in temperature :)
- Sat Mar 13, 2021 11:14 pm
- Forum: Second Order Reactions
- Topic: Determining slow step
- Replies: 22
- Views: 1190
Re: Determining slow step
yes, you usually look at the overall rate law and see which reactants are part of it, and then match that to the elementary step which also has the same reactants. Or, the problem would give you the slow step. Only the reactants in the slow step are included in the rate law. If you see a reactant i...
- Sat Mar 13, 2021 11:05 pm
- Forum: Phase Changes & Related Calculations
- Topic: state properties
- Replies: 13
- Views: 825
Re: state properties
Thank you for asking, I was also wondering the same thing!
- Sat Mar 13, 2021 11:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy vs Entropy
- Replies: 39
- Views: 3218
Re: Enthalpy vs Entropy
Basically:
Enthalpy would be the the amount of heat released/gained
Entropy would be the disorder :)
Enthalpy would be the the amount of heat released/gained
Entropy would be the disorder :)
- Sat Mar 13, 2021 10:57 pm
- Forum: Calculating Work of Expansion
- Topic: when is change in internal energy 0
- Replies: 10
- Views: 1892
Re: when is change in internal energy 0
Gillian Gabrielsen2F wrote:ΔU = q+w
For this problem, q= 5.50 kJ.
Since the expansion work is done against a contant pressure, w= -PΔV
So ΔU = 5.50 kJ + (-PΔV)
ΔV= 1.846L - .345L and P = 750/760 atm (converting Torr to atm).
Hope this helps!
thank you for your explanation! :)
- Sat Mar 13, 2021 10:56 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Is thermal mugs an example of an isolated system?
- Replies: 38
- Views: 2067
Re: Is thermal mugs an example of an isolated system?
It would if no heat is moving around! :)
- Sat Mar 13, 2021 10:47 pm
- Forum: Ideal Gases
- Topic: Standard temperature
- Replies: 10
- Views: 774
Re: Standard temperature
I just saw another post similar to this and it's SATP (298K) :)
- Sat Mar 13, 2021 10:46 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Temperature of Standard Conditions
- Replies: 5
- Views: 526
Re: Temperature of Standard Conditions
Valerie Tran 2B wrote:I saw this on a different chem community post but my understanding is "standard conditions" uses 298K (gases, liquids, and solids). 273K is for STP which is a subset of standard conditions and specifically refers to ideal gases.
Thank you for clarifying! :D
- Sat Mar 13, 2021 10:39 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta G and G naught
- Replies: 46
- Views: 4603
Re: Delta G and G naught
As others have said, Delta G naught is at standard conditions :)
- Sat Mar 13, 2021 10:32 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Isolated Systems
- Replies: 15
- Views: 862
Re: Isolated Systems
As everyone has said, it's theoretical :)
- Fri Mar 12, 2021 12:39 am
- Forum: *Nucleophiles
- Topic: FInal
- Replies: 11
- Views: 1721
Re: FInal
i definitely think going over the book will be very helpful!
- Fri Mar 12, 2021 12:38 am
- Forum: *Free Energy of Activation vs Activation Energy
- Topic: Sapling #15 Wk.9-10
- Replies: 6
- Views: 14041
Re: Sapling #15 Wk.9-10
For this problem use the arrhenius equation k = Ae^−EaRT where A is the frequency factor 8.07×1011. You should convert the temperature into Kelvin from Celsius, rearrange the equation to kA = e^−EaRT and take the natural log of both sides so that your equation becomes Ea =−RTln(k/A). You can then i...
- Fri Mar 12, 2021 12:36 am
- Forum: Second Order Reactions
- Topic: Termolecular
- Replies: 43
- Views: 2348
Re: Termolecular
Thanks to all the replies; They were extremely helpful! :)
- Fri Mar 12, 2021 12:35 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Textbook Problem 4.43
- Replies: 3
- Views: 394
Re: Textbook Problem 4.43
I'm not completely sure but I think it is an error
- Fri Mar 12, 2021 12:32 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: catalyst's effect on equilibrium
- Replies: 9
- Views: 867
Re: catalyst's effect on equilibrium
I think that's correct! The catalyst speeds up the forward reaction by lowering the activation energy, but it also speeds up the reverse reaction by lowering its activation energy by the same factor. The catalyst wouldn't affect equilibrium because its forward and reverse effects would "cancel...
- Fri Mar 12, 2021 12:31 am
- Forum: *Electrophiles
- Topic: Is F a electrophile or nucleophile?
- Replies: 16
- Views: 2909
Re: Is F a electrophile or nucleophile?
VincentLe_3A wrote:F would be an electrophile as it would need one more to get a full octet. On the other hand, F- is nucleophile as it has an extra electron.
Thanks for giving some more information! :)
- Fri Mar 12, 2021 12:22 am
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Bomb Calorimeter
- Replies: 17
- Views: 853
Re: Bomb Calorimeter
Yep! they're sealed and insulated :)
- Fri Mar 12, 2021 12:18 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Standard Molar Entropy
- Replies: 2
- Views: 298
Re: Standard Molar Entropy
Hi! I believe that at absolute zero, or 0 Kelvin, a perfect crystal is the only thing with an entropy of zero. However, this is not actually possible since we cannot actual reach a temperature of 0K. Also, standard molar entropy implies that it is at standard conditions (298K) so 0K is not possible...
- Fri Mar 12, 2021 12:17 am
- Forum: Ideal Gases
- Topic: Reversing Reactions
- Replies: 68
- Views: 2473
Re: Reversing Reactions
i know it's repetitive but as you already know, it's 1/K :)
- Fri Mar 12, 2021 12:16 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Stability/Favorable
- Replies: 5
- Views: 375
Re: Stability/Favorable
greater concentration is favored :)
- Sun Feb 14, 2021 9:13 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: qrev vs q
- Replies: 21
- Views: 2000
Re: qrev vs q
Christine Ma 3L wrote:q and qrev are both just heat terms, but qrev refers to heat from a reversible expansion. When systems are approximated as reversible (like when we're trying to calculate the maximum work), we use qrev.
Thanks for this! I was still a little confused from other replies ;-;
- Sun Feb 14, 2021 9:09 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: What are the three ways to find Delta H?
- Replies: 7
- Views: 12701
Re: What are the three ways to find Delta H?
Hi! I remember Dr. Lavelle stating that some of these are more reliable than the others, and I was wondering which ones are more accurate and why. Thank you! Hi! Out of the three methods (Hess's Law, Bond Enthalpies, and Standard Enthalpies of Formation), using bond enthalpies is the least accurate...
- Sun Feb 14, 2021 9:08 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Entropy trends from 4H
- Replies: 8
- Views: 598
Re: Entropy trends from 4H
It's repetitive but larger molecules have higher entropy because of their mass
- Sun Feb 14, 2021 9:06 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling #8 Week 5-6
- Replies: 4
- Views: 277
Re: Sapling #8 Week 5-6
I'm having the same issue so I'm hoping someone can help answer :,)
- Sun Feb 14, 2021 9:03 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Sapling question 7
- Replies: 8
- Views: 446
Re: Sapling question 7
I'm not entirely sure because I'm still stuck on the rest of that problem. I was wondering if you were able to solve it and if so, how?
- Thu Feb 04, 2021 9:44 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong acids/bases
- Replies: 10
- Views: 593
Re: Strong acids/bases
Summer_Corona 3L wrote:For strong acids I use SO I Brought NO Clean Clothes. I don't know one for bases but Lavelle had said if the cation is from groups one or two then it's strong.
SO- HSO4
I- HI
Brought- HBr
NO-HNO3
Clean- HCl
Clothes- HClO3 or HClO4
Thanks for this, I hope it'll make them easier to remember!
- Thu Feb 04, 2021 9:40 pm
- Forum: Phase Changes & Related Calculations
- Topic: Why does steam cause severe burns?
- Replies: 22
- Views: 1764
Re: Why does steam cause severe burns?
As many have mentioned, it is in relation to the energy in steam in comparison to its boiling liquid counterpart.
- Thu Feb 04, 2021 9:36 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Gibb Free Energy
- Replies: 3
- Views: 130
Re: Gibb Free Energy
Gibbs free energy (ΔG) equals the work exchanged by the system with its surroundings, minus the work of the pressure force. The best way to identify if a problem is asking you to use the equation is to see if the problem is dealing with energy work and pressure 9x out of 10 you can use Gibbs's equa...
- Thu Feb 04, 2021 9:12 pm
- Forum: Biological Examples (*DNA Structural Transitions, etc.)
- Topic: Biological systems
- Replies: 7
- Views: 1509
Re: Biological systems
Thanks for asking this question. I was also confused but I'm glad there are responses! :)
- Thu Feb 04, 2021 9:05 pm
- Forum: Environment, Fossil Fuels, Alternative Fuels
- Topic: Fuel cells
- Replies: 12
- Views: 2207
Re: Fuel cells
Orly Termeie 3I wrote:If Delta G is negative the fuel cell would be feasible and thus, the cell potential would have to be positive. Since the products would have a lower energy than the reactants which is favorable.
Thank you for explaining it! :D
- Thu Feb 04, 2021 9:03 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Residual Entropy
- Replies: 5
- Views: 196
Re: Residual Entropy
Someone answered this question before with: "Residual entropy is the entropy that remains after molecules stop moving at 0 degrees kelvin. The entropy lies within the orientation of the atoms of the molecule." I thought it was the clearest explanation so I hope it's also helpful for you! :)
- Thu Feb 04, 2021 8:58 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: N value in degeneracy equation
- Replies: 4
- Views: 200
Re: N value in degeneracy equation
The N value is the number of molecules present. The base for this is the number of states that are possible for the molecules. These states can be determined by simulating the various different positions that the molecules can be in, in the system. This is crucial to the measure of entropy as entro...
- Thu Feb 04, 2021 8:51 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Memorizing molar entropies
- Replies: 15
- Views: 685
Re: Memorizing molar entropies
lucky for us, these are given! :D
- Thu Feb 04, 2021 8:42 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Degeneracy in different phases
- Replies: 2
- Views: 167
Re: Degeneracy in different phases
Hi! I'm not exactly sure if Dr. Lavelle said why in his lecture, but the way I like to think about it is that solids and liquids are held together by intermolecular forces. In order for these IMF to be present, the molecules of the solid or liquid need to be oriented a certain way so that they can ...
- Thu Feb 04, 2021 8:40 pm
- Forum: Phase Changes & Related Calculations
- Topic: Sapling HW Weeks 3&4 #10
- Replies: 6
- Views: 240
Re: Sapling HW Weeks 3&4 #10
Hi! You need to account for both the heat needed to melt the ice and the heat needed to raise the temperature of the melted ice/water to the final temperature. This is how I would set up the problem: heat needed to melt ice + heat needed to raise temp. of water = - heat released to lower temp. of w...
- Mon Jan 25, 2021 12:58 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: isochoric
- Replies: 10
- Views: 955
Re: isochoric
Sophia Dinh 1D wrote:what is the difference between isochoric and isometric?
Isochoric: value of volume is constant
Isometric: measurements are constant
:)
- Mon Jan 25, 2021 12:52 am
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Should we memorize any standard states?
- Replies: 3
- Views: 193
Re: Should we memorize any standard states?
The learning objectives don't explicitly say to memorize standard states, but it does say that you have to recognize when a substance in its standard state. If you can do this without memorizing a bunch of standard states, that's probably easier. Here's a link to a different post talking about how ...
- Mon Jan 25, 2021 12:50 am
- Forum: Phase Changes & Related Calculations
- Topic: Steam
- Replies: 33
- Views: 1974
Re: Steam
The steam causes more severe burns because of the large amount of energy it takes to turn liquid water into steam. If you think about the steam as condensing when it hits your skin, then the steam must release all the energy it took to phase change into vapor, and therefore it releases a lot of hea...
- Mon Jan 25, 2021 12:40 am
- Forum: Calculating Work of Expansion
- Topic: Integral
- Replies: 9
- Views: 611
Re: Integral
It's already mentioned but it's because the volume's value is changing :)
- Mon Jan 25, 2021 12:24 am
- Forum: Phase Changes & Related Calculations
- Topic: when to assume x is insignificant
- Replies: 86
- Views: 7106
Re: when to assume x is insignificant
Hi, I was confused about this too, but I remember Dr. Lavelle saying that if the equilibrium constant is under 1x10^-3 then you can assume that the change is insignificant, but I've read that 1x10^-4 is more accurate. It can be assumed to be insignificant if it is less than this and doesn't change ...
- Mon Jan 25, 2021 12:10 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ΔGionization
- Replies: 10
- Views: 856
Re: ΔGionization
As said by others, I don't believe so :(
- Sun Jan 24, 2021 11:46 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Determining pH
- Replies: 18
- Views: 827
Re: Determining pH
Jenaye Brelland 2I wrote:The -log[H+] will result in the pH. The -log[OH-] will result in the pOH. Remember that p in pH means -log. So pH is -logH+ and pOH is -logOH-.
Hi Jenaye! I'm glad to see you explanation written out! It serves as a little reminder :)
- Sun Jan 24, 2021 11:42 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Enthalpy
- Replies: 26
- Views: 1207
Re: Enthalpy
I know it's a bit repetitive hearing the same thing but a state function means that, in order to determine its value, we only need both the initial and final state.
- Sun Jan 24, 2021 11:25 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: sapling week 2 #5
- Replies: 15
- Views: 540
Re: sapling week 2 #5
Im on like my 9th attempt for this problem and still can't seem to find what I am doing wrong. I am following the same procedure as above, could someone help? My Kb=3.435x10^-5 and my pH=9.705. First you would need to find the value of [OH-] by subtracting your given pH value from 14 and then apply...
- Sun Jan 24, 2021 10:40 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pka, Ph, charged and neutral species
- Replies: 7
- Views: 409
Re: Pka, Ph, charged and neutral species
I'm pretty sure that is correct!
(if not, please let me know ;-;)
(if not, please let me know ;-;)
- Sun Jan 17, 2021 4:24 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: q vs k
- Replies: 62
- Views: 2617
Re: q vs k
Q is the reaction quotient and can be used to figure out which direction the reaction will shift in order to reach equilibrium. K > Q: reaction proceeds forward, R --> P. K < Q: reaction proceeds in reverse direction, P --> R. Q = K: system is at equilibrium, no shift to either left or right Thank ...
- Sun Jan 17, 2021 4:21 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Using Ka vs Kb
- Replies: 8
- Views: 497
Re: Using Ka vs Kb
Hannah Biju 1E wrote:If there is formation of an acid (H3O+), then you should use Ka. If there is formation of a base (OH-), then you should use Kb.
Thank you for your clarification! I had totally forgotten about this!
- Sun Jan 17, 2021 4:18 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc vs. Q
- Replies: 5
- Views: 233
Re: Kc vs. Q
Q and K don't represent the same number. K is a constant that stays the same (unless you change the temp) and shows you the ratio of the concentration of products over the concentration of reactants. Q actually can help you determine if a reaction is at equilibrium and if it isn't how it will shift...
- Sun Jan 17, 2021 4:16 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: The Quadratic equation
- Replies: 7
- Views: 522
Re: The Quadratic equation
I'm also struggling on the application of the quadratic equation. I'm not sure how to use it correctly or when to use it :,)
- Sun Jan 17, 2021 4:14 am
- Forum: Ideal Gases
- Topic: Gas constant R
- Replies: 26
- Views: 1288
Re: Gas constant R
As many before me have said, it is a constant :)
R = 8.3144598 J/mol·K
R = 8.3144598 J/mol·K
- Sun Dec 13, 2020 12:54 am
- Forum: Dipole Moments
- Topic: Hydrogen Bonding
- Replies: 6
- Views: 398
Re: Hydrogen Bonding
Mohamed Mido wrote:Any NOF atom that has lone pairs can H-bond. Alos all hydrogens bonded to NOF can H-Bond. It can be tricky because Hydrogen atoms that are bonded to Carbon can't H-bond, but NOF atoms bonded to Carbon can, so you'll have to remember that.
Thank you for this!
- Sun Dec 13, 2020 12:52 am
- Forum: Bronsted Acids & Bases
- Topic: Sapling #12
- Replies: 6
- Views: 1031
Re: Sapling #12
I remember hearing that since O is pulling towards H, it means a weak bond. As you mentioned, their electronegativity is involved :)
- Sun Dec 13, 2020 12:50 am
- Forum: Trends in The Periodic Table
- Topic: O versus N Ionization Energy
- Replies: 9
- Views: 565
Re: O versus N Ionization Energy
I myself am not entirely sure. I just know it has something to do with their electron configuration. Thank you for asking this question since I was also wondering the same thing!
- Fri Dec 11, 2020 3:20 am
- Forum: Polyprotic Acids & Bases
- Topic: How can you tell
- Replies: 18
- Views: 1020
Re: How can you tell
The anion has to have more than one h atom :)
- Fri Dec 11, 2020 3:09 am
- Forum: Resonance Structures
- Topic: Resonance Hyrbid
- Replies: 11
- Views: 646
Re: Resonance Hyrbid
this is a bit of a dumb question but what exactly do we mean when we say something is delocalized? i've seen it in a couple of posts and im a bit confused as to what that exactly means Hi the term delocalized is used to refer to an electrons activity! so if it is delocalized, it means that it is no...
- Sun Dec 06, 2020 2:11 am
- Forum: Bronsted Acids & Bases
- Topic: neutralization
- Replies: 3
- Views: 239
Re: neutralization
connie ma 2B wrote:to clarify what someone else said, complete neutralization only occurs if its a strong acid reacting with a strong base. if its strong/weak or weak/weak then i dont think complete neutralization occurs.
Thank you for this! I found it much easier to understand.
- Sun Dec 06, 2020 2:09 am
- Forum: Hybridization
- Topic: Unhybridized Orbitals in Relation to Hybridized Orbitals
- Replies: 4
- Views: 304
Re: Unhybridized Orbitals in Relation to Hybridized Orbitals
Well it depends. If you remember earlier in the quarter, when we first reviewed unhybridized orbitals, we learned that p orbitals have 3 different orientations-- px, py, and pz. Each p orbital was on a different axis. The reason the unhybridized p orbital was perpendicular rather than in plane was ...
- Sun Dec 06, 2020 2:03 am
- Forum: Resonance Structures
- Topic: Stability
- Replies: 13
- Views: 742
Re: Stability
Because electrons are delocalized (meaning they are not bound to just one location, for example, a double bond), this makes the molecule more stable. Resonance structures allow for different bond configurations between atoms in a molecule. The electrons have "different options" in terms o...
- Sun Dec 06, 2020 2:02 am
- Forum: Significant Figures
- Topic: When should I start looking at sig figs?
- Replies: 31
- Views: 1590
Re: When should I start looking at sig figs?
I always keep as many decimal points while I'm working on the math and once I've got my final answer, I focus on sig figs :)
- Sun Dec 06, 2020 1:53 am
- Forum: Coordinate Covalent Bonds
- Topic: Coordinate Covalent Bonds and Covalent Bonds
- Replies: 7
- Views: 849
Re: Coordinate Covalent Bonds and Covalent Bonds
coordinate covalent: 1 atom donates BOTH electrons
regular covalent: 2 atoms share 1 electron
regular covalent: 2 atoms share 1 electron
- Fri Nov 27, 2020 9:03 pm
- Forum: Lewis Structures
- Topic: Ring structures
- Replies: 4
- Views: 170
Re: Ring structures
CesarLec1 wrote:I believe that for our purposes, when we see a molecule with 6 carbon atoms, it will most likely be in a ring structure
Thank you for explaining this, I did not know that was the case! :)
- Fri Nov 27, 2020 8:59 pm
- Forum: Trends in The Periodic Table
- Topic: Ionic radius trends
- Replies: 7
- Views: 611
Re: Ionic radius trends
Hi! As the charge become more positive, the ionic radius usually decreases. This is because there are fewer electrons in the atom. As there are fewer electrons, the electrons are pulled closer to the nucleus of the atom. When an ion is more negative, the ionic radius increases because the electrons...
- Fri Nov 27, 2020 8:54 pm
- Forum: Empirical & Molecular Formulas
- Topic: Periodic Table and Calculations
- Replies: 21
- Views: 1666
Re: Periodic Table and Calculations
jordanginyard_ wrote:What is a good calculator to use for chemistry? what's a good periodic table because sometimes I get the problems wrong with the numbers that are used on the periodic table?
I currently use the ti-84 just because it's the one calculator I'm familiar with! :)
- Fri Nov 27, 2020 8:47 pm
- Forum: Octet Exceptions
- Topic: Question on Radicals
- Replies: 7
- Views: 476
Re: Question on Radicals
VSU_2G wrote:As others have said, I believe they're the same thing! Free radicals are involved in oxidizing elements, and I feel like an element with an odd number of electrons would want electrons from other substances, so I believe they are interchangeable terms.
Thanks for the clarification!
- Fri Nov 27, 2020 8:46 pm
- Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
- Topic: ionic liquids
- Replies: 8
- Views: 965
Re: ionic liquids
It's a salt in it's liquid state and as many have said, it has a low melting point :)
- Sat Nov 21, 2020 2:21 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Determining Polarity
- Replies: 6
- Views: 530
Re: Determining Polarity
I use the electronegativity trend and shape to help me find out if the molecule is polar. So, if a molecule is polar, that means one side is hogging the electrons more than the other. So if more electronegative atoms are on one side of the molecule, then it is polar. If the electronegative molecule...
- Sat Nov 21, 2020 2:18 am
- Forum: Sigma & Pi Bonds
- Topic: Hybridization
- Replies: 7
- Views: 426
Re: Hybridization
Is there a specific benefit for hybridization? Why does it occur in the first place? Hybridization occurs to fix the imbalance in the energy levels of the electrons when an atom bonds using electrons from different orbitals. This will result in a more stable molecule! Thank you for clarifying! I di...
- Sat Nov 21, 2020 2:17 am
- Forum: Ionic & Covalent Bonds
- Topic: Covalent Character
- Replies: 33
- Views: 1581
Re: Covalent Character
I just remember that the smaller the difference in electronegativity, the more covalent it is! :)
- Sat Nov 21, 2020 2:16 am
- Forum: Lewis Structures
- Topic: Identifying Lewis Acids and Bases
- Replies: 8
- Views: 503
Re: Identifying Lewis Acids and Bases
I'm working on this too because I get confused at times, but the Lewis structures (of course) help me with identifying the Lewis Acids and Bases. If a molecule for example has lone pairs to give would be examples of bases. Central atoms that are electron deficient (maybe having a positive formal ch...
- Sat Nov 21, 2020 2:14 am
- Forum: Student Social/Study Group
- Topic: Post Midterm Blues
- Replies: 71
- Views: 3594
Re: Post Midterm Blues
I'm already scared for our final knowing how I did for our second midterm... ;-;
- Sun Nov 15, 2020 1:10 pm
- Forum: Lewis Structures
- Topic: Nitrite vs Nitrate
- Replies: 17
- Views: 1290
Re: Nitrite vs Nitrate
I hope we won't have to know what they are based on their names because I'm confused on how to do that, but I don't think we'll need to because he hasn't taught us. I agree but thankfully many have mentioned that we are not required to memorize them and that they will be provided for us should it c...
- Sun Nov 15, 2020 1:07 pm
- Forum: Coordinate Covalent Bonds
- Topic: When do we use it
- Replies: 9
- Views: 390
Re: When do we use it
I also had the same question. Thank you for asking!
- Thu Nov 12, 2020 4:54 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation Number
- Replies: 11
- Views: 587
Re: Oxidation Number
To find the oxidation number of ClO4- you can use a simple equation. Assuming oxygen will have a (-2) oxidation number and knowing the total charge of the molecule is (-1) you can write the equation Cl+4(-2)=-1. Solving for Cl gets you Cl=7, which means the oxidation number for Cl is +7. I apologiz...
- Thu Nov 12, 2020 4:49 pm
- Forum: Octet Exceptions
- Topic: How to tell
- Replies: 6
- Views: 522
Re: How to tell
An element can have an expanded octet if its energy level has access to a d orbital. For example, the elements in the 3rd period have access to the 3d subshell, so elements like Phosphorus and Sulfur can have more than the traditional octet. However, elements in the second period like Nitrogen or O...
- Thu Nov 12, 2020 4:30 pm
- Forum: Sigma & Pi Bonds
- Topic: Triple bond?
- Replies: 21
- Views: 897
Re: Triple bond?
darchen3G wrote:Single bond: 1 sigma
Double bond: 1 sigma 1 pi
Triple bond: 1 sigma 2 pi
Quadruple bond: 1 sigma 2 pi 1 delta
Thank you for this!!!
- Sat Nov 07, 2020 6:34 pm
- Forum: Einstein Equation
- Topic: E=hv vs E=hf
- Replies: 15
- Views: 869
Re: E=hv vs E=hf
Brian Bui 2A wrote:As others said, they are interchangeable! However v (Greek letter) for frequency has a little curve on the left while v for velocity is just straight, if that helps. Very nit-picky details!
Thanks for this! I probably would not have noticed that tiny detail.
- Sat Nov 07, 2020 6:26 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Equations Coefficient Question
- Replies: 24
- Views: 2692
Re: Balancing Equations Coefficient Question
As everyone has said, as long as you multiply both by the same number, you should be fine! :)
- Sat Nov 07, 2020 6:11 pm
- Forum: SI Units, Unit Conversions
- Topic: Using a Calculator
- Replies: 10
- Views: 518
Re: Using a Calculator
Another good tip for scientific calculators is to set it SCI mode. Usually, the default is on FLO, but SCI shows results in scientific notation which saves time from homework and test questions. I believe our week 0 sapling optional homework noted this. I didn't know this was a feature! Thank you f...
- Sat Nov 07, 2020 6:10 pm
- Forum: SI Units, Unit Conversions
- Topic: Using a Calculator
- Replies: 10
- Views: 518
Re: Using a Calculator
Yes!! If I don't add parenthesis in some occasions, it gives me a totally wrong exponent and it messes everything up!
- Sat Nov 07, 2020 6:06 pm
- Forum: Significant Figures
- Topic: How to use Scientific Notation
- Replies: 9
- Views: 575
Re: How to use Scientific Notation
When multiplying two numbers in scientific notation, multiply their coefficients and add their exponents. When dividing two numbers in scientific notation, divide their coefficients and subtract their exponents. If you remember from math where we were taught how to multiply and divide with exponent...
- Sat Nov 07, 2020 6:04 pm
- Forum: SI Units, Unit Conversions
- Topic: SI Unit for Mass
- Replies: 10
- Views: 736
Re: SI Unit for Mass
Hi! I am pretty sure mass has to be in kg. In examples where I'm given grams, I convert to kg before using any equation.
- Sat Oct 31, 2020 1:05 am
- Forum: Properties of Electrons
- Topic: Constructive vs Destructive
- Replies: 6
- Views: 355
Re: Constructive vs Destructive
Hello! Conceptually, constructive interference occurs when the troughs line up with each other, and when the peaks line up with each other. This results in constructive interference because in either case, the amplitude will increase . And because the amplitude increases, this signals that construc...
- Sat Oct 31, 2020 12:54 am
- Forum: DeBroglie Equation
- Topic: Electron Affinity Sapling
- Replies: 6
- Views: 357
Re: Electron Affinity Sapling
Edward Tang 2E wrote:Actually I dont think you need the wavelength equation. Just do e=(c/wavelength)*plancks to figure out the energy of the photon, convert that to eV by dividing 1.602e-19 and you're good
Literally thank you so much for this. I've been struggling with a similar question the entire week.
- Sat Oct 31, 2020 12:52 am
- Forum: Balancing Chemical Reactions
- Topic: Molar Mass
- Replies: 23
- Views: 1934
Re: Molar Mass
What I normally do is use the entire number from the periodic table and after I'm done with calculations, I round. :)
- Sat Oct 31, 2020 12:45 am
- Forum: SI Units, Unit Conversions
- Topic: Angstrom
- Replies: 6
- Views: 546
Re: Angstrom
Hi! I usually put the 2 units I want to convert into a fraction. For example, I know that 1m=100cm, so the fraction can be \frac{1m}{100cm} or \frac{100cm}{1m} . Because the denominator and numerator are the same, both fractions equal to 1. Then, I can multiply a value by this fraction, and cancel ...
- Sat Oct 31, 2020 12:43 am
- Forum: Ionic & Covalent Bonds
- Topic: ligands
- Replies: 7
- Views: 1684
Re: ligands
They're electron pair donors!
- Sat Oct 24, 2020 8:39 pm
- Forum: SI Units, Unit Conversions
- Topic: Midterm
- Replies: 26
- Views: 1191
Re: Midterm
Thankfully it's a multiple choice midterm and if I remember correctly, my TA said there weren't going to be too many questions.
- Sat Oct 24, 2020 8:32 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Uncertainty equation with ±
- Replies: 10
- Views: 303
Re: Uncertainty equation with ±
Thank you for asking this question! I have been looking for answers for some time now!
- Sat Oct 24, 2020 7:57 pm
- Forum: Significant Figures
- Topic: How would you round these numbers
- Replies: 10
- Views: 698
Re: How would you round these numbers
You actually did it correctly!! I also had my doubts about my rounding at first.
- Sat Oct 24, 2020 7:47 pm
- Forum: *Black Body Radiation
- Topic: Midterm
- Replies: 14
- Views: 761
Re: Midterm
Nope! It's not going to be on our midterm (thankfully)!!
- Sat Oct 24, 2020 7:35 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Advice for studying
- Replies: 92
- Views: 7141
Re: Advice for studying
I personally just plan on working on practice problems and rewatching the video modules since those really seem to help me. I'm also going to try to make time to attend workshops before my midterm. Good luck studying!!
- Sun Oct 18, 2020 7:19 pm
- Forum: Significant Figures
- Topic: rounding during equations
- Replies: 14
- Views: 601
Re: rounding during equations
I've found out the hard way that it's best not to round until we are finished with our problem. If we don't, the answer might be off.
- Sun Oct 18, 2020 6:20 pm
- Forum: Photoelectric Effect
- Topic: Light Intensity
- Replies: 23
- Views: 559
Re: Light Intensity
Hi there! You are correct, the wavelength/frequency did not change. It is the photons that affect the brightness of light, so it increased.
- Sun Oct 18, 2020 6:01 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Reactions Order
- Replies: 49
- Views: 6380
Re: Balancing Chemical Reactions Order
Hi! I personally do not really have a particular order I follow when I'm balancing chemical equations. However, I have heard that you should first start off with the element that is repeated the most.
I hope that helps!
I hope that helps!
- Sun Oct 18, 2020 5:53 pm
- Forum: Significant Figures
- Topic: Sig Figs
- Replies: 5
- Views: 336
Re: Sig Figs
Hi Heather! I also have some trouble with sig figs but I remember someone shared this website so I hope it help you as much as it helped me!
http://chemistry.bd.psu.edu/jircitano/sigfigs.html
http://chemistry.bd.psu.edu/jircitano/sigfigs.html
- Sun Oct 18, 2020 5:48 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Equations
- Replies: 11
- Views: 622
Re: Balancing Chemical Equations
Hi there! For the example, CO4, the correct answer would be:
C= 1 and O=4
simply because there is no coefficient next to carbon the same way there is one for hydrogen.
C= 1 and O=4
simply because there is no coefficient next to carbon the same way there is one for hydrogen.
- Sat Oct 10, 2020 3:27 pm
- Forum: Empirical & Molecular Formulas
- Topic: Sapling Week 1 #8
- Replies: 23
- Views: 1411
Re: Sapling Week 1 #8
Hi! I remember when I saw this problem and was completely overwhelmed but it's actually a lot easier than it seems! To find the molecular formula, simply count how many of each there are for C, H, and O. Upon counting, you'll see you have C6H8O6. To find the mass of the compound, you have to multipl...
- Sat Oct 10, 2020 2:54 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: sapling hw #7
- Replies: 17
- Views: 680
Re: sapling hw #7
After reading some of the replies, I'm afraid I have a silly question.
People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why.
Thank you!
People are saying to "multiply 0.325 with 590.1g" but my question is what they did to get 0.325 and why.
Thank you!
- Sat Oct 10, 2020 2:39 pm
- Forum: Balancing Chemical Reactions
- Topic: Order of Balancing Rxns
- Replies: 23
- Views: 668
Re: Order of Balancing Rxns
Hi! So, what I usually do is I try to balance the element that there is more of. Afterwards, I sort of "wing it" and try different numbers until the equation is balanced. I know it's not the best method because it requires some time but I'd like to hear other ways to do so! In regards to k...
- Sat Oct 10, 2020 2:34 pm
- Forum: Significant Figures
- Topic: How to deal with significant figures in decimals with zeros.
- Replies: 20
- Views: 1219
Re: How to deal with significant figures in decimals with zeros.
Hi Jenaye! I literally was so confused as well when I was working on the Sapling homework not too long ago. But riding off of what others have said, the numbers are important if they're between 2 integers. However, I am still having some trouble understanding the decimal rule.