Search found 96 matches

by Astha Patel 2J
Sun Feb 21, 2021 8:27 pm
Forum: Student Social/Study Group
Topic: Post Midterm 2 De-stressing
Replies: 86
Views: 231

Re: Post Midterm 2 De-stressing

305405193 wrote:Is Wanda Vision that good? I LOVE MARVEL so I've been debating on seeing it, but everyone says its so GOODD. Please let me know if it's worth skipping studying time LOL


Literally go binge it rn. It's so good
by Astha Patel 2J
Sun Feb 21, 2021 8:24 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Boiling point
Replies: 6
Views: 28

Re: Boiling point

Phase changes occur at equilibrium because all the energy is used for changing the states rather than heating up the compounds.
by Astha Patel 2J
Sun Feb 21, 2021 8:22 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: entropy positive value
Replies: 29
Views: 57

Re: entropy positive value

I think he was referring to the second law, which states that an isolated system's entropy will always increase over time. A system can have a negative change in entropy, but overall somewhere in the universe, the entropy will increase.
by Astha Patel 2J
Sun Feb 21, 2021 8:19 pm
Forum: Balancing Redox Reactions
Topic: Salt Bridge Clarification
Replies: 3
Views: 13

Re: Salt Bridge Clarification

Salt bridges allow ions to go from the cathode solution to the anode solution to counter the increasing negative charge on the cathode side. If salt bridges didn't exist, the transfer of electrons would eventually stop. I'm not sure how exactly they move, but the driving force behind it may just be ...
by Astha Patel 2J
Sun Feb 21, 2021 8:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Different Standard Reduction Potentials
Replies: 2
Views: 12

Re: Different Standard Reduction Potentials

Don't quote me on this but I think it has to do with how well a compound acts as an oxidizing agent, or how likely it is to be reduced. That explains why Flourine gas (fluorine has very good electron pulling power), has such a high standard potential.
by Astha Patel 2J
Sun Feb 21, 2021 8:06 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Stable vs Unstable Gibbs Free Energy
Replies: 16
Views: 55

Re: Stable vs Unstable Gibbs Free Energy

If a compound is thermodynamically stable, then forming it would be thermodynamically spontaneous in terms of Gibbs free energy. Therefore, A negative Gibbs free energy for the formation of some compound indicates that it is stable. If the Gibbs free energy is positive, then it's unstable.
by Astha Patel 2J
Sun Feb 14, 2021 9:16 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Homework Problem 4F.7
Replies: 1
Views: 11

Re: Homework Problem 4F.7

For both parts a and b, you'll use the equation deltaS = nCln(T2/T1). The difference between the two parts will be due to different heat capacity values, C. For the constant pressure, the heat capacity of a monatomic gas is (3/2)R, and for constant volume, the heat capacity is (5/2)R, where R is the...
by Astha Patel 2J
Sun Feb 14, 2021 9:06 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: isometric and enthalpy
Replies: 3
Views: 36

Re: isometric and enthalpy

I think another thing to remember is that in a situation with constant volume, the heat, q, is equal to the change in internal energy. Also, when there is no change in volume, gases do no work, so that's why the work term gets removed from deltaU = q + w
by Astha Patel 2J
Sun Feb 14, 2021 9:02 pm
Forum: Student Social/Study Group
Topic: Fav Shows of the Moment
Replies: 100
Views: 228

Re: Fav Shows of the Moment

Nathan Lao 2I wrote:Wandavision is literally so good. I just don't like how each episode is a cliffhanger. They answer our questions about the previous episode but then introduce way more at the end of each one. The suspense kills me.



I get more and more confused the more episodes I watch
by Astha Patel 2J
Sun Feb 14, 2021 9:01 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Sapling #6
Replies: 6
Views: 28

Re: Sapling #6

Basically, you have to find the change in entropy due to volume and then combine it with the change in entropy due to temperature change. Use nRln(v2/v1) and nCln(T2/T1) and then add the two together.
by Astha Patel 2J
Sun Feb 14, 2021 8:58 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes: delta H and delta S
Replies: 5
Views: 27

Re: Phase Changes: delta H and delta S

When you have a phase change, for example going from a solid to a liquid, delta H is positive because heat is going into the system to make this phase change happen. Going from a solid to a liquid is also a more disordered state, and therefore delta S would have to be positive.
by Astha Patel 2J
Sun Feb 14, 2021 8:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: qrev vs q
Replies: 19
Views: 56

Re: qrev vs q

qrev is heat from a reversible expansion/compression, but q is just a heat term. Make sure that you use qrev when solving for entropy changes.
by Astha Patel 2J
Sun Feb 07, 2021 7:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Can heat capacities be negative?
Replies: 52
Views: 157

Re: Can heat capacities be negative?

Heat capacities talk about how much heat a system needs to gain, and thus will always be positive. However, when you have a loss of heat (negative q) that's usually because delta T is negative.
by Astha Patel 2J
Sun Feb 07, 2021 7:55 pm
Forum: Student Social/Study Group
Topic: Midterm 2 study tips
Replies: 26
Views: 75

Re: Midterm 2 study tips

Do the textbook problems, they are your friends. I haven't gone to any UA workshops, but I've heard they're good practice. Also, I like reading over the outlines to make sure I know all of the bullet points.
by Astha Patel 2J
Sun Feb 07, 2021 7:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: HW 14
Replies: 8
Views: 36

Re: HW 14

Yeprem wrote:but for V in PV=nRT which V value do i use, V1 or V2?

Use V1, because the number of moles won't change when you expand a gas.
by Astha Patel 2J
Sun Feb 07, 2021 7:45 pm
Forum: Student Social/Study Group
Topic: Superbowl Sunday
Replies: 25
Views: 112

Re: Superbowl Sunday

this did not age well
by Astha Patel 2J
Sun Feb 07, 2021 7:44 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: converting T to kelvin
Replies: 46
Views: 482

Re: converting T to kelvin

The best thing to do to be safe would be to check the units of whatever it is you're trying to solve or the gas constant given in the problem. Also, if you are using the change in temperature then celsius and kelvins are interchangeable because a change of +1 degrees celsius is the same as a change ...
by Astha Patel 2J
Sun Feb 07, 2021 7:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Combustion = Exothermic
Replies: 23
Views: 78

Re: Combustion = Exothermic

When you form the bonds to make water and carbon dioxide, that releases more energy than it takes to break the bonds in the reactants. Also, think of combustion as producing heat, so you know that it's "releasing" heat, and would therefore be exothermic.
by Astha Patel 2J
Sun Feb 07, 2021 7:40 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sapling Week 3/4 #13
Replies: 8
Views: 39

Re: Sapling Week 3/4 #13

At constant pressure, work done by the system will be -delta n *RT. Therefore, for a system to DO work, the change in n would have to be a positive number, so the reaction should produce a greater number of moles of gas compared to the moles of gas used. For the equation A(s) + B(s) -> C(g), the del...
by Astha Patel 2J
Sun Jan 31, 2021 9:43 pm
Forum: Phase Changes & Related Calculations
Topic: State Property
Replies: 11
Views: 81

Re: State Property

Heat depends on the path taken, so it's not a state function. However, enthalpy is.
by Astha Patel 2J
Sun Jan 31, 2021 7:21 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sapling #8 Weeks 3&4
Replies: 10
Views: 75

Re: Sapling #8 Weeks 3&4

The delta H given in the problem refers to the KJ per mole of S8. Therefore multiple the delta H with the number of moles of S8 (1.31).
by Astha Patel 2J
Sun Jan 31, 2021 7:13 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar Heat Capacity
Replies: 11
Views: 44

Re: Molar Heat Capacity

You'll probably use it in some practice problems, if they give you moles of a substance and molar heat capacity. Otherwise, we usually use specific heat.
by Astha Patel 2J
Sun Jan 31, 2021 7:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: delta H vs delta U
Replies: 11
Views: 49

Re: delta H vs delta U

Delta H is the change in heat energy whereas delta U is the change in total energy
by Astha Patel 2J
Sun Jan 31, 2021 7:09 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calculus for thermochemistry
Replies: 5
Views: 40

Re: Calculus for thermochemistry

Maybe some upper divisions have calculus pre-reqs but I'm not sure.
by Astha Patel 2J
Sun Jan 31, 2021 7:06 pm
Forum: Phase Changes & Related Calculations
Topic: Vapor vs gas
Replies: 92
Views: 239

Re: Vapor vs gas

Yes! Vapors are gases.
by Astha Patel 2J
Sun Jan 24, 2021 9:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Q9
Replies: 2
Views: 20

Re: Sapling Q9

If pH<pKa, then it is in a more acidic environment. This means that the species will act as a base and will then accept a proton. Therefore in the solution, there is more HA present. If pH>pKa, then it's in a basic environment. This means that the species will act as an acid and donate its proton. T...
by Astha Patel 2J
Sun Jan 24, 2021 9:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #2 Week 2
Replies: 5
Views: 22

Re: Sapling #2 Week 2

You'll have to test the assumption. So when you do your ice tables and solve for x (assuming that x is negligible in the denominator), then take x and divide it by the concentration of the initial solution. If this is greater than 5% then the assumption doesn't work and you have to use quadratic. To...
by Astha Patel 2J
Sun Jan 24, 2021 8:37 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: pKa
Replies: 14
Views: 57

Re: pKa

They both equal each other.
by Astha Patel 2J
Sun Jan 24, 2021 8:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: derive pKW = pH + pOH [ENDORSED]
Replies: 3
Views: 38

Re: derive pKW = pH + pOH [ENDORSED]

I'm pretty sure that's all you need to know because that is how you derive that equation.
by Astha Patel 2J
Sun Jan 24, 2021 8:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: acids and bases
Replies: 4
Views: 42

Re: acids and bases

Acids generally have a carboxyl group or an acidic hydrogen. If a compound is a group 1 hydroxide, or a group 1/2 oxide, it is a base. When you have salt compounds, what I usually do is split the compound into two ions. If the compound is strong, its conjugate acid/base will be weak so the solution ...
by Astha Patel 2J
Sun Jan 17, 2021 7:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5% rule
Replies: 5
Views: 49

Re: 5% rule

I would always plug it in to check if it's less than 5% because it really depends on the concentration of the initial solution. That's why I trust the 10^-4 limit rather than 10^-3.
by Astha Patel 2J
Sun Jan 17, 2021 7:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kc
Replies: 9
Views: 55

Re: K vs Kc

Correct me if I'm wrong, but I believe that Kc is just a more specific way to describe K. However, if you want to convert between Kc and Kp, then I think the equation is Kp= Kc(RT)^delta(n), where delta n is the change in the number of moles (moles of products - moles of reactants). So calculating ...
by Astha Patel 2J
Sun Jan 17, 2021 4:43 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Sapling Week 1 #6
Replies: 7
Views: 43

Re: Sapling Week 1 #6

So what you do is write the equation for Q, which is the same as Kc but the concentrations aren't equilibrium concentrations. So, Q = ([NH3]^2) / ([H2]^3 * [N2])
Then, just plug in the concentrations that they gave in the problem.
by Astha Patel 2J
Sun Jan 17, 2021 4:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #10
Replies: 3
Views: 36

Re: Sapling Week 1 #10

Since the problem gives you the equilibrium concentrations already, all you need to do is write the equation for Kc which would be Kc = [NO2]^2 / [N2O4]. The NO2 is squared because one mol of N2O4 yields two moles of NO2. Then just plug in the values.
by Astha Patel 2J
Sun Jan 17, 2021 4:31 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How do we know a compound is a weak acid or base?
Replies: 6
Views: 28

Re: How do we know a compound is a weak acid or base?

For the problems in 6D, when they give you a compound, what I usually do is split the compound into two ions. For example, 6D.15 asks to find the pH of 0.19M NH4Cl. So looking at this compound you need to figure out whether its acidic or basic so you know whether to use Ka or Kb when solving for the...
by Astha Patel 2J
Sun Jan 10, 2021 7:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #7
Replies: 3
Views: 25

Re: Sapling #7

Because the question says "immediately after the temperature change", the concentrations of the reactants or products haven't changed yet so Q is the same. However, because the reaction is endothermic, increasing the temperature will increase K (favoring the products).
by Astha Patel 2J
Sun Jan 10, 2021 5:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kc
Replies: 9
Views: 55

Re: K vs Kc

Correct me if I'm wrong, but I believe that Kc is just a more specific way to describe K. However, if you want to convert between Kc and Kp, then I think the equation is Kp= Kc(RT)^delta(n), where delta n is the change in the number of moles (moles of products - moles of reactants).
by Astha Patel 2J
Sun Jan 10, 2021 5:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 51.13c
Replies: 4
Views: 28

Re: 51.13c

Large equilibrium constants favor products, and a small equilibrium constant favors the reactants. At 1000K, F2 has a larger equilibrium constant than Cl2 (you'll probably solve for this in parts a and b). A large equilibrium constant in this example would favor the products of dissociation, therefo...
by Astha Patel 2J
Sun Jan 10, 2021 5:54 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Stable Reactants and Products
Replies: 7
Views: 42

Re: Stable Reactants and Products

Large equilibrium constants favor products, and a small equilibrium constant favors the reactants. As an example, think about the dissociation of F2 and Cl2. At 1000K, F2 has a larger equilibrium constant than Cl2. A large equilibrium constant in this example would favor the products of dissociation...
by Astha Patel 2J
Sun Jan 10, 2021 5:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling hw 5
Replies: 14
Views: 102

Re: Sapling hw 5

You want to use equations that, when added together, give you the overall reaction. Sometimes, you'll have to flip one of the equations (use 1/K) or you may have to multiply all of the reactants and products of an equation by some constant (use K^constant). When you alter the individual equations, r...
by Astha Patel 2J
Tue Dec 15, 2020 10:13 pm
Forum: Conjugate Acids & Bases
Topic: conjugate acids and bases
Replies: 6
Views: 49

Re: conjugate acids and bases

The conjugate acid will gain a H+ (add 1 to the charge), and the conjugate base will lose a H+ (subtract 1 from the charge).
by Astha Patel 2J
Tue Dec 15, 2020 10:09 pm
Forum: Coordinate Covalent Bonds
Topic: Polydentate Ligands
Replies: 8
Views: 93

Re: Polydentate Ligands

I would look for lone pairs on the lewis structure and then determine whether those pairs are in a favorable orientation, like with spacers. That's the only way to bind to the same central metal.
by Astha Patel 2J
Tue Dec 15, 2020 10:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Why is CO (carbon monoxide) monodentate?
Replies: 6
Views: 56

Re: Why is CO (carbon monoxide) monodentate?

The structure doesn't have spacers making it impossible for two lone pairs to become bonding pairs simultaneously. It would try and bend the bond.
by Astha Patel 2J
Tue Dec 15, 2020 9:59 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: How do you determine the stronger base/acid?
Replies: 7
Views: 65

Re: How do you determine the stronger base/acid?

I would memorize the seven strong acids, because that rules out all the other acids as weak. For the relative strengths of the weaker acids it depends on the acid type: 1) binary acids are some HA acid, where A is some anion. With these acids, the strength increases as the electron affinity of A inc...
by Astha Patel 2J
Tue Dec 15, 2020 9:52 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation #s help
Replies: 5
Views: 52

Re: Oxidation #s help

To reiterate what others have said, you take the charge of the element that interacts with the complex ion (which is what is in brackets). The total charge of the compound should be zero, so you know that the charge on the element(s) outside of the brackets should equal the negative of the total cha...
by Astha Patel 2J
Sun Dec 06, 2020 6:54 pm
Forum: Naming
Topic: -ate
Replies: 17
Views: 115

Re: -ate

-ate is used when the complex ion has a negative charge. Usually, the coordination compound will contain some metal cation in front of the complex ion in the bracket.
by Astha Patel 2J
Sun Dec 06, 2020 6:45 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate Ligands We Have to Know
Replies: 3
Views: 36

Re: Polydentate Ligands We Have to Know

I believe that oxalato, en, edta, dien, and carbonato are generally the ones we need to know as they come up in textbook problems. I haven't encountered any other ones.
by Astha Patel 2J
Sun Dec 06, 2020 6:44 pm
Forum: Hybridization
Topic: Clarification on Hybridization
Replies: 2
Views: 25

Re: Clarification on Hybridization

The regions of electron density should equal the orbitals that are available from the hybridizations. sp = 2 orbitals, so, therefore, two regions of electron density. sp3 = 4 orbitals, so therefore four regions of electron density.
by Astha Patel 2J
Sun Dec 06, 2020 6:32 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Pka and Ka
Replies: 6
Views: 53

Re: Pka and Ka

Ka is the acid dissociation constant and pKa is the negative log of the Ka value.
by Astha Patel 2J
Sun Dec 06, 2020 6:30 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number and Regions of density
Replies: 8
Views: 62

Re: Coordination Number and Regions of density

Coordination numbers refer to the number of bonds between the central metal and ligands. Regions of density could include lone pairs of electrons which does not pertain to coordination numbers.
by Astha Patel 2J
Sun Dec 06, 2020 6:28 pm
Forum: Naming
Topic: Anion Naming
Replies: 7
Views: 79

Re: Anion Naming

Yes! Only prefixes that specify the number of ligand molecules is used. Anything outside of the bracket that pertains to the complex ion doesn't use a prefix.
by Astha Patel 2J
Sun Nov 29, 2020 11:59 pm
Forum: Ionic & Covalent Bonds
Topic: Polar and Nonpolar
Replies: 28
Views: 196

Re: Polar and Nonpolar

The shape of the molecule can show whether dipoles are positioned to cancel each other out.
by Astha Patel 2J
Sun Nov 29, 2020 5:37 pm
Forum: Limiting Reactant Calculations
Topic: Combustion
Replies: 10
Views: 125

Re: Combustion

Oxygen gas can be assumed in excess during combustion reactions unless stated otherwise.
by Astha Patel 2J
Sun Nov 29, 2020 5:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E27
Replies: 4
Views: 9

Re: Textbook Problem 2E27

Since we will most likely be provided the molecular formal of compounds that we are unfamiliar with, you can probably search it up and still get good practice from doing the lewis structure. The past two midterms have always given us the molecular formulas so I wouldn't worry about it too much.
by Astha Patel 2J
Sun Nov 29, 2020 5:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2F3
Replies: 4
Views: 37

Re: Textbook Problem 2F3

After drawing the Lewis structure, the first bonds (single) between any two atoms would be sigma bonds and any additional bonds between the atoms (making it a double or triple bond) would be pi bonds.
by Astha Patel 2J
Sun Nov 29, 2020 5:28 pm
Forum: Limiting Reactant Calculations
Topic: Cl vs Cl2
Replies: 9
Views: 99

Re: Cl vs Cl2

Chlorine and Oxygen gas are both diatomic molecules and will be written Cl2 and O2.
by Astha Patel 2J
Sun Nov 29, 2020 5:26 pm
Forum: Sigma & Pi Bonds
Topic: Sapling Q #16
Replies: 14
Views: 140

Re: Sapling Q #16

Molecules with resonance structures where the double or triple bond can be moved among different atoms consist of pi bonds, so depending on the lewis structures and whether resonance is possible, that can show whether the bonds are delocalized.
by Astha Patel 2J
Sun Nov 22, 2020 8:49 pm
Forum: Lewis Structures
Topic: Electron Density
Replies: 14
Views: 133

Re: Electron Density

Electron density is the probability of finding an electron in a given region of an orbital. Greater electron density can indicate the more negative pole of a molecule.
by Astha Patel 2J
Sun Nov 22, 2020 7:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: CH3F Molecular Shape
Replies: 7
Views: 73

Re: CH3F Molecular Shape

CH3F is tetrahedral and I believe that the bond angles will decrease by a small amount.
by Astha Patel 2J
Sun Nov 22, 2020 6:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 21
Views: 126

Re: Bond Angles

To reiterate what others have said since bond angles are experimentally determined, I would remember the angles for the parent shapes where all bond angles are equal and then when larger areas of electron density are present then the bond angles would decrease.
by Astha Patel 2J
Sun Nov 22, 2020 6:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 10
Views: 86

Re: Shape

I believe it would be linear.
by Astha Patel 2J
Sun Nov 22, 2020 6:29 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Finding negative pole of a molecule
Replies: 4
Views: 50

Re: Finding negative pole of a molecule

The best way would be to compare electronegativities and whichever atom has the greater electronegativity (electron pulling power) would be the negative end of the pole. The relative differences in electronegativity would also tell us which ones have a greater dipole moment (greater difference in el...
by Astha Patel 2J
Sun Nov 15, 2020 4:06 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Energy Levels in electron configurations
Replies: 5
Views: 31

Re: Energy Levels in electron configurations

So basically the 4s subshell gets filled first before 3d. This is because, at the time where there are no electrons in the 3d subshell, the 4s subshell is lower in energy. However, once the 3d subshell starts getting filled, it has lower energy than the 4s subshell and therefore gets written before...
by Astha Patel 2J
Sun Nov 15, 2020 4:04 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Sapling week 5 & 6 #5
Replies: 20
Views: 128

Re: Sapling week 5 & 6 #5

The formal charge on the carbon is a -2.
by Astha Patel 2J
Sun Nov 15, 2020 4:03 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Atomic orbitals + probability
Replies: 1
Views: 15

Re: Atomic orbitals + probability

I think we just need to know that orbitals aren't pre-existing but rather describe the probabilities of finding electrons at a specific energy level.
by Astha Patel 2J
Sun Nov 15, 2020 4:00 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge Textbook Question
Replies: 3
Views: 18

Re: Formal Charge Textbook Question

Make sure you're using the pdf solutions of the textbook that's in the sapling website. It might just be an error in the solutions in the back of the ebook because in the pdf, the left structure is the favored one because of the minimized formal charges.
by Astha Patel 2J
Sun Nov 15, 2020 3:58 pm
Forum: Quantum Numbers and The H-Atom
Topic: Scandium Exception
Replies: 1
Views: 27

Re: Scandium Exception

Yes, as soon as the 3d subshell starts getting filled, it is written before the 4s subshell because it is at a lower energy level.
by Astha Patel 2J
Sun Nov 15, 2020 3:56 pm
Forum: Student Social/Study Group
Topic: Favorite TV shows
Replies: 189
Views: 1214

Re: Favorite TV shows

GOSSIP GIRL !!!

and as soon as you finish start YOU
by Astha Patel 2J
Sun Nov 15, 2020 3:55 pm
Forum: Resonance Structures
Topic: lewis base or acid
Replies: 15
Views: 124

Re: lewis base or acid

A lewis acid accpets electrons and therefore is usually a cation, a molecule where the central atom is electron deficient, or a molecule with polar double bonds. A lewis base donates the electrons and therefore is usually an anion, a molecule where atoms have excess electrons or a molecule with lone...
by Astha Patel 2J
Sun Nov 15, 2020 3:53 pm
Forum: Ionic & Covalent Bonds
Topic: Polarity of bonds vs molecules
Replies: 6
Views: 19

Re: Polarity of bonds vs molecules

The ability for a molecule to be non-polar yet consist of polar bonds is due to the ability for dipoles to cancel out. This can be seen after looking at the shape of the molecule (for example, a symmetrical molecule will most likely have dipoles that cancel each other out).
by Astha Patel 2J
Sun Nov 08, 2020 6:25 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Energy Levels in electron configurations
Replies: 5
Views: 31

Re: Energy Levels in electron configurations

So basically the 4s subshell gets filled first before 3d. This is because, at the time where there are no electrons in the 3d subshell, the 4s subshell is lower in energy. However, once the 3d subshell starts getting filled, it has lower energy than the 4s subshell and therefore gets written before ...
by Astha Patel 2J
Sun Nov 08, 2020 6:23 pm
Forum: Trends in The Periodic Table
Topic: Elements that form Cations
Replies: 6
Views: 25

Re: Elements that form Cations

Electrons on the left side of the periodic table are more likely to form cations because of their low ionization energies and low electron affinities. They are more likely to lose their outermost electron as it isn't held as tightly by nuclear charge.
by Astha Patel 2J
Sun Nov 08, 2020 6:20 pm
Forum: Ionic & Covalent Bonds
Topic: Sapling #1
Replies: 3
Views: 16

Re: Sapling #1

Your structure seems right to me. Did the question ask to put formal charges?
by Astha Patel 2J
Sun Nov 08, 2020 6:18 pm
Forum: Lewis Structures
Topic: Sapling Week 5/6 HW #9
Replies: 2
Views: 20

Re: Sapling Week 5/6 HW #9

I think since the total formal charge of the ion is -1, it is considered more stable as opposed to a different lewis structure in which the oxygens would be given a formal charge value that isn't one even though they are more electronegative. I think when comparing lewis structures to see which is m...
by Astha Patel 2J
Mon Nov 02, 2020 8:52 pm
Forum: Trends in The Periodic Table
Topic: Sizes of ions vs elements
Replies: 4
Views: 39

Sizes of ions vs elements

How is it that Na+ is smaller than Cl-, but elemental Na is larger than elemental Cl?
by Astha Patel 2J
Sun Nov 01, 2020 8:24 pm
Forum: Quantum Numbers and The H-Atom
Topic: Determining Quantum Numbers
Replies: 5
Views: 49

Re: Determining Quantum Numbers

So the first three quantum numbers specify an orbital. Each orbital can hold a maximum of 2 electrons. So the first three quantum numbers can specify at most 2 electrons. Once the fourth quantum number is given, then the four numbers specify a single electron.
Hope this helps :)
by Astha Patel 2J
Sun Nov 01, 2020 8:22 pm
Forum: Photoelectric Effect
Topic: sapling problem
Replies: 2
Views: 41

Re: sapling problem

Someone had asked this a couple weeks ago and this was my reasoning: So the problem gives the energy requried to remove an electron. In this problem, the work function should equal the energy of the incoming photon, so hv= work function. Substitute frequency for c/lamda so that you can solve for wav...
by Astha Patel 2J
Sun Nov 01, 2020 8:19 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 1
Views: 23

Re: Schrodinger Equation

I'm not 100% sure but I believe we just need to understand it conceptually and what it represents because it helps explain quantum numbers in orbitals, but I don't think we need to do calculations with wave functions because in the textbook many of the problems required integration.
by Astha Patel 2J
Sun Nov 01, 2020 8:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quantum Number Memorizing tips
Replies: 2
Views: 12

Re: Quantum Number Memorizing tips

For the quantum number l that specifies the subshell, you should probably just memorize that s = 0, p=1, and so on. For the Magnetic quantum number that gives you the specific orbital, i would remember that it depends on what l is : l, l-1, ...., -l
by Astha Patel 2J
Sun Nov 01, 2020 8:14 pm
Forum: DeBroglie Equation
Topic: average wavelength
Replies: 3
Views: 34

Re: average wavelength

Use deBroglie's wavelength equation where wavelength = h/p, and p is momentum. p=mv. The problem gives you the velocity of the particle so all you have to do is plug it into the equation.
by Astha Patel 2J
Sun Nov 01, 2020 8:12 pm
Forum: Photoelectric Effect
Topic: Participation points
Replies: 16
Views: 176

Re: Participation points

As long as the five posts are timestamped before 11:59pm of Sunday of every week, then you'll get the credit for all the posts.
by Astha Patel 2J
Sat Oct 24, 2020 5:54 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question about the Delta X and what it stands for
Replies: 6
Views: 54

Re: Question about the Delta X and what it stands for

Delta X refers to uncertainty in position. In a problem where they say that the electron is bound by an atom, the uncertainty of the position would be the length of the atom because the electron could be anywhere in that range. If the problem said something like the uncertainty was 10 nm +/- 2nm, th...
by Astha Patel 2J
Sat Oct 24, 2020 5:49 pm
Forum: Properties of Electrons
Topic: Schrodinger's wave equation
Replies: 4
Views: 59

Re: Schrodinger's wave equation

The mathematical representation of wave functions from Schrodinger's wave equation are essentially math models of specific orbitals. So each orbital has a unique wave function that specifically works for that orbital. So yes, it could be used as a form of identification, but I'm not too sure that it...
by Astha Patel 2J
Sat Oct 24, 2020 5:44 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook 1B.28
Replies: 1
Views: 35

Textbook 1B.28

Hi guys :) So this is an even numbered problem from the textbook. I know how to do part a, but I'm confused on part b and c, specifically on the mass of the Li+ atom. The uncertainty principle has negligible consequences for macroscopic objects. However, the properties of nanoparticles, which have d...
by Astha Patel 2J
Sat Oct 24, 2020 5:32 pm
Forum: Photoelectric Effect
Topic: Wavelength in Photoelectric Effect
Replies: 7
Views: 81

Re: Wavelength in Photoelectric Effect

It depends on the surface metal that has the electrons. Some metals require a greater frequency than others., so there's no exact range.
by Astha Patel 2J
Sun Oct 18, 2020 3:23 pm
Forum: Photoelectric Effect
Topic: Sapling Week 2,3,4 #9
Replies: 2
Views: 53

Re: Sapling Week 2,3,4 #9

So the problem gives the energy requried to remove an electron. In this problem, the work function should equal the energy of the incoming photon, so hv= work function. Substitute frequency for c/lamda so that you can solve for wavelength. This gives you the answer to the first part. For the second ...
by Astha Patel 2J
Sun Oct 18, 2020 1:44 pm
Forum: *Black Body Radiation
Topic: Stefann-Boltzmann law and Wein's Law
Replies: 3
Views: 28

Stefann-Boltzmann law and Wein's Law

Will we need to know the Stefann-Boltzmann Law and Wein's Law for Black Body radiation for Midterm 1?
by Astha Patel 2J
Sat Oct 17, 2020 9:22 pm
Forum: Properties of Electrons
Topic: Homework Problem 1B-15b.
Replies: 1
Views: 21

Re: Homework Problem 1B-15b.

Hey guys, I am having trouble starting off problem number 15b. The velocity of an electron that is emitted from a metallic surface by a photon is 3.6 × 10 3 km ⋅ s − 1 . (a) What is the wavelength of the ejected electron? (b) No electrons are emitted from the surface of the metal until the frequenc...
by Astha Patel 2J
Sat Oct 17, 2020 9:08 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Module question 42
Replies: 1
Views: 19

Re: Module question 42

The equation E=-hR/n^2 gives you the energy of an electron at a principle energy level, n. The problem gives you the final energy level n=4. Using the equation, find the final energy of the electron when n=4 (-hR/16). The frequency given in the problem is equal to the change in energy of the electro...
by Astha Patel 2J
Sat Oct 17, 2020 9:00 pm
Forum: Einstein Equation
Topic: Delta E equation
Replies: 1
Views: 32

Re: Delta E equation

3.29*10^15 Hz is Rydberg's constant. It represents R in the equation E= -hR/n^2.
by Astha Patel 2J
Sat Oct 17, 2020 8:58 pm
Forum: Einstein Equation
Topic: Changing sign from neg to pos in E=hv
Replies: 4
Views: 30

Re: Changing sign from neg to pos in E=hv

I'm not entirely sure about this but I believe that the energy of the photon given off is the negative of the change in energy of the electron when it drops to a lower energy level. Since the change in energy of the electron is negative, the energy of the photon would have the opposite sign, hence t...
by Astha Patel 2J
Sun Oct 11, 2020 12:06 pm
Forum: Empirical & Molecular Formulas
Topic: order of formulas [ENDORSED]
Replies: 5
Views: 143

Re: order of formulas [ENDORSED]

There exists something called the Hill System where if there is a molecule with Carbon the order of the formula will be Carbon, Hydrogen, and the other elements in alphabetical order. If there is no carbon in the molecule, then the elements are written in alphabetical order.
by Astha Patel 2J
Sun Oct 11, 2020 12:03 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Sapling week 1 hw problem 9
Replies: 4
Views: 59

Re: Sapling week 1 hw problem 9

You can do this because of conservation of mass. In a chemical reaction mass is neither created nor destroyed so the initial and final mass should be equal. Therefore when you add the separate masses of Carbon and Hydrogen and Oxygen together, you'll get the mass of the original sample.
by Astha Patel 2J
Wed Oct 07, 2020 4:18 pm
Forum: Properties of Electrons
Topic: Question 35 Wave Properties of Electrons Post Module
Replies: 3
Views: 37

Re: Question 35 Wave Properties of Electrons Post Module

To calculate the wavelength you should use the equation wavelength = h/p where h is plank's constant and p is momentum (mass times velocity). Convert the velocity to meters per second, which is the units required for the equation to work. You should get 6.94 *10^-38. Since this wavelength is extreme...
by Astha Patel 2J
Wed Oct 07, 2020 4:12 pm
Forum: Empirical & Molecular Formulas
Topic: Rounding EF to Integers
Replies: 6
Views: 64

Re: Rounding EF to Integers

Since you use the empirical formula's molecular mass to solve for the molecular formula (using the molecular mass usually given in the context of the problem), it makes calculations easier if Empirical formulas are in the lowest whole numbers. You'll still get the correct answer using decimals but i...
by Astha Patel 2J
Mon Oct 05, 2020 12:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Post Module Q
Replies: 5
Views: 70

Re: Atomic Spectra Post Module Q

I actually didn't use that equation, though I probably should have. I followed the steps in the module example exactly (calculate Efinal - Einitial to get delta E) except I used E=(hc)/(wavelength) in the end to get the wavelength instead of the frequency. Should I generally avoid this method when ...

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