Search found 97 matches

by Eileen Si 1G
Sat Feb 15, 2020 1:34 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 4F. 11
Replies: 3
Views: 11

Re: 4F. 11

You can use the ideal gas law, PV = nRT to calculate the amount of moles, since every other value for the equation is given.
by Eileen Si 1G
Sat Feb 15, 2020 1:29 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Irreversible, Adiabatic
Replies: 3
Views: 20

Irreversible, Adiabatic

What is the delta entropy of the surroundings and system during an irreversible expansion, and is it any different to an adiabatic system where q = 0?
by Eileen Si 1G
Sat Feb 15, 2020 1:22 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium
Replies: 5
Views: 19

Equilibrium

Do delta G, delta H, and delta S have nonzero values at equilibrium, or are they equal to 0 since there is no net change occurring due to the system being at equilibrium?
by Eileen Si 1G
Sat Feb 15, 2020 1:13 am
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: 4H.5
Replies: 4
Views: 14

Re: 4H.5

Adding on, for part c, ethene is a gas, while polyethylene is a solid, so naturally, ethene will have higher entropy than polyethylene.
by Eileen Si 1G
Sat Feb 15, 2020 1:07 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs free energy
Replies: 5
Views: 13

Gibbs free energy

Why does Gibbs free energy depend on the equilibrium constant and pressure? Also, is Gibbs free energy a state function?
by Eileen Si 1G
Tue Feb 04, 2020 10:54 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Topics on the Midterm
Replies: 22
Views: 85

Re: Topics on the Midterm

According to Lavelle's website, the topics covered on the midterm will be Chemical Equilibrium, Acids and Bases, Thermochemistry, and Thermodynamics, so yes, you should know all of Thermodynamics.
by Eileen Si 1G
Tue Feb 04, 2020 10:52 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4D.7
Replies: 2
Views: 12

Re: 4D.7

I believe that they will include the temperature in the given problem, however, I would still double-check with your TA to make sure.
by Eileen Si 1G
Tue Feb 04, 2020 10:51 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4D.9
Replies: 1
Views: 34

Re: 4D.9

After calculating the enthalpy for the TNT, which should be in the units of kJ.mol-1, you need to convert this value into kJ.g-1 by using the molar mass for TNT. Then, this is when you bring in the density value. First, you need to convert it into g.L-1 and multiply it by the enthalpy that you found...
by Eileen Si 1G
Mon Feb 03, 2020 10:32 pm
Forum: Phase Changes & Related Calculations
Topic: Heating Curve
Replies: 6
Views: 27

Re: Heating Curve

Adding onto what the person before me said, the steeper the heating curve, the lower the heat capacity, and vice versa - the shallower the heating curve, the higher the heat capacity.
by Eileen Si 1G
Mon Feb 03, 2020 10:29 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat capacity
Replies: 3
Views: 13

Re: Heat capacity

Heat capacity is the ratio of the heat supplied to the rise in temperature produced. Specifically for ideal gases, it requires more heat to achieve the same rise in temperature for constant pressure than it does at constant volume. While at constant volume, all the heat supplied goes into raising th...
by Eileen Si 1G
Mon Jan 27, 2020 10:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4C.13
Replies: 3
Views: 29

Re: 4C.13

Yes, you're on the right track, but for q of ice, you also need to account for the fact that the ice melting into water also gives off energy that needs to be added to the calculation for q=mCdeltaT, so it would be the grams of ice converted into moles and multiplied by the standard enthalpy of phys...
by Eileen Si 1G
Mon Jan 27, 2020 10:00 pm
Forum: Calculating Work of Expansion
Topic: Calculating Work
Replies: 2
Views: 33

Calculating Work

When would you know to use w=-P*delta V versus w=-nRTln(V2/V1) to calculate work of expansion? (Like in homework 4A.5)
by Eileen Si 1G
Mon Jan 27, 2020 9:53 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: 4A.1
Replies: 12
Views: 38

Re: 4A.1

A closed system can exchange energy with its surroundings, but not matter, while an isolated system cannot exchange either energy nor matter. For example, an example of a closed system is a pan with a lid, on top of a stove. The pan is exchanging heat energy from the fire, but not the amount of matt...
by Eileen Si 1G
Mon Jan 27, 2020 9:45 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q vs. delta H
Replies: 6
Views: 52

Re: q vs. delta H

q is the amount of heat that is transferred into or out of a system and is measured in J (joules). delta H is the change in enthalpy of a system and is measured in kJ (or J) * mol-1.
by Eileen Si 1G
Mon Jan 27, 2020 9:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4C.3
Replies: 4
Views: 56

Re: 4C.3

For part a, I believe it's 343K for the final temperature and 935.1J for the change in enthalpy, and part b it's 374K for the final temperature and 947.6J for the change in enthalpy.
by Eileen Si 1G
Mon Jan 27, 2020 9:29 pm
Forum: Phase Changes & Related Calculations
Topic: Chem 14A Final Pickup
Replies: 8
Views: 31

Re: Chem 14A Final Pickup

You can pick them at 3034 Young Hall, but I'm not sure when we are allowed to pick them up or if we can go at anytime this week.
by Eileen Si 1G
Wed Jan 22, 2020 12:37 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Liquids
Replies: 6
Views: 23

Solids and Liquids

To clarify, solids and liquids would not be included in a K expression, right? So, only liquids and aqueous molecules would be involved?
by Eileen Si 1G
Wed Jan 22, 2020 12:31 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: suggestions
Replies: 16
Views: 63

Re: suggestions

Khan Academy and Bozeman Science
by Eileen Si 1G
Wed Jan 22, 2020 12:26 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6B. 11
Replies: 3
Views: 36

Re: 6B. 11

To find the mass of Na2O in the first flask, you take the molar concentration of NaOH that you calculated in part aii) and divide by 0.2 L (200 mL) as given in the problem to cancel out the volume and just get moles of NaOH. Then, you need to use stoichiometry to convert moles of NaOH to moles of Na...
by Eileen Si 1G
Wed Jan 22, 2020 12:19 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating K
Replies: 15
Views: 56

Calculating K

Is it possible to calculate K for an unbalanced equation? Or can you only calculate Q?
by Eileen Si 1G
Wed Jan 22, 2020 12:13 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5.33
Replies: 4
Views: 20

Re: 5.33

Catalysts increase the rate of the reaction, but emerge unchanged from the reaction, so they do not affect the amount of product formed.
by Eileen Si 1G
Wed Jan 22, 2020 12:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 6D.7a
Replies: 3
Views: 29

Re: Homework 6D.7a

Yes, you are on the right track. For HClO, the Ka = 3.0 x 10^-8, and the variable in the Ka expression would be the amount of molar concentration of HClO, which you can find since you are given the pH. So, it would be Ka = 3.0 x 10^-8 = [HClO]^2/x-[HClO], and you would just solve for x.
by Eileen Si 1G
Wed Jan 22, 2020 12:00 am
Forum: Administrative Questions and Class Announcements
Topic: Chem 14A Final Pick-up
Replies: 1
Views: 51

Chem 14A Final Pick-up

Does anyone know when we can pick up the finals from chem 14A? I know that it is this week, but am unsure if we can pick them up at any time, or if there a certain time-frame in which we can pick them up?
by Eileen Si 1G
Mon Jan 13, 2020 5:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Autoprotolysis of water endo or exo?
Replies: 4
Views: 13

Re: Autoprotolysis of water endo or exo?

Adding onto what the previous person said, because the autoionization of water is an endothermic reaction, the change in enthalpy is positive, because endothermic reactions require heat, which causes the products to be more favored than the reactants.
by Eileen Si 1G
Mon Jan 13, 2020 4:48 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook question 5J.11
Replies: 3
Views: 15

Re: Textbook question 5J.11

To add on, the reaction favors the products on the right side, and we learned today in lecture that a reaction that favors the formation of products is endothermic because they require heat. On the other hand, exothermic reactions give off heat when forming products, so hearing will favor the format...
by Eileen Si 1G
Mon Jan 13, 2020 4:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 5.39
Replies: 1
Views: 16

Homework 5.39

In the textbook, the question asks to use information from Table 5E.2, but I can't seem to find it anywhere. By any chance, is this just a typo where they meant to refer to Table 5G.2 instead? If not, on which page can I find Table 5E.2?
by Eileen Si 1G
Mon Jan 13, 2020 4:29 pm
Forum: Administrative Questions and Class Announcements
Topic: 14A Final Pickup
Replies: 5
Views: 41

Re: 14A Final Pickup

Can we pick them up at any time, or is there a certain time-frame in which we can pick them up?
by Eileen Si 1G
Mon Jan 13, 2020 4:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changing Pressure
Replies: 3
Views: 20

Changing Pressure

How does increasing or decreasing the partial pressure of a reactant affect the partial pressure of the product, and vice versa for a change in product and its effect on the reactant?
by Eileen Si 1G
Mon Jan 13, 2020 4:16 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Homework 5J.5b
Replies: 2
Views: 18

Homework 5J.5b

Question 5J.5b in the homework gives the following reaction: H20(aq) + C(s) = H2(g) + CO(g). Will the reactants or products be favored by an increase in total pressure due to compression, and why?
by Eileen Si 1G
Tue Jan 07, 2020 4:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 86

Q vs K

This may be an obvious question, but what is the difference between Q (reaction quotient) and K (equilibrium constant)?
by Eileen Si 1G
Tue Jan 07, 2020 4:41 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Homework 5J.1c
Replies: 3
Views: 30

Homework 5J.1c

In the equation, CO(g) + H2O(g) = CO2(g) + H2(g), if the concentration of CO is increased, would the concentration of H2 also increase? Or would it remain the same and not change?
by Eileen Si 1G
Tue Jan 07, 2020 4:39 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's and Endo/Exothermic
Replies: 5
Views: 41

Re: Le Chatelier's and Endo/Exothermic

Exothermic equations have a negative value because heat energy is being released into the environment, and the enthalpy of the products is lower than the reactants.
by Eileen Si 1G
Tue Jan 07, 2020 4:37 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: How to make ICE box
Replies: 15
Views: 89

Re: How to make ICE box

By looking at the balanced chemical equation. If the molecule does not have a stoichiometric coefficient, then the change is simply x. If the molecule does has a stoichiometric coefficient, then the change is the coefficient * x. Also, if the molecule is a reactant, then the change is negative, but ...
by Eileen Si 1G
Mon Jan 06, 2020 11:59 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Homework 5I.23
Replies: 3
Views: 31

Re: Homework 5I.23

Also, would you be able to divide the concentrations (in moles) by 10.0 L in the beginning so the concentrations in the equilibrium table are in mol.L^-1 instead of mol and calculate the concentrations of the different products and reactants from there instead of dividing the moles by 10.0 L at the ...
by Eileen Si 1G
Mon Jan 06, 2020 11:53 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Homework 5I.23
Replies: 3
Views: 31

Homework 5I.23

For number 5I.23 in the homework, why is the initial concentration (in moles) for CH4(g) 0 instead of 0.478?
by Eileen Si 1G
Sun Dec 08, 2019 2:58 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Pi bond order
Replies: 3
Views: 30

Pi bond order

When listing the bond order for pi bonds, will it always be 2p hybridized? For example, if the sigma bond was sigma(C2sp^2, C2sp^2), would the pi bond then be pi(C2p, C2p) hybridized?
by Eileen Si 1G
Tue Dec 03, 2019 6:23 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong vs. Weak Acids and Bases
Replies: 4
Views: 31

Re: Strong vs. Weak Acids and Bases

Thank you! Does anyone know of any other traits about acid/base strengths/weaknesses that you should be on the lookout for?
by Eileen Si 1G
Tue Dec 03, 2019 6:20 pm
Forum: Lewis Structures
Topic: 2D.5
Replies: 2
Views: 26

Re: 2D.5

You can calculate this by looking at the electronegativity values for each of the elements and subtracting the difference between them. If the electronegativity difference is greater than 2, then the bond is ionic, so for this problem, the closer the differences are to 2, the more ionic they are.
by Eileen Si 1G
Tue Dec 03, 2019 6:13 pm
Forum: Administrative Questions and Class Announcements
Topic: Review Session
Replies: 1
Views: 34

Re: Review Session

Hi! I don't know if you stayed until close to 6pm, but he ended up coming in late and is still going over the review material.
by Eileen Si 1G
Mon Dec 02, 2019 4:58 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong vs. Weak Acids and Bases
Replies: 4
Views: 31

Strong vs. Weak Acids and Bases

How do you distinguish the difference between a strong versus weak acid or a strong versus weak base? Does it have to do with plain memorization, or are there any tricks or ways to tell the difference between them?
by Eileen Si 1G
Mon Dec 02, 2019 4:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Lavelle review sessions
Replies: 3
Views: 33

Re: Lavelle review sessions

In his Final Exam Review Sessions sheet, it states that he's going to have his own review where he'll go over his past test questions, but it'll be during regular lecture times, so he won't host any of his own extra review sessions outside of scheduled lectures.
by Eileen Si 1G
Mon Dec 02, 2019 4:45 pm
Forum: Administrative Questions and Class Announcements
Topic: Final tips
Replies: 19
Views: 149

Re: Final tips

The UA's are also going to be holding another Final Review Session this Friday night. They posted a practice final under the name "Marshmallow" that should mimic the sort of problems that will be on the final.
by Eileen Si 1G
Wed Nov 27, 2019 11:31 pm
Forum: Lewis Acids & Bases
Topic: Conjugates
Replies: 3
Views: 21

Re: Conjugates

What about for bases?
by Eileen Si 1G
Wed Nov 27, 2019 11:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Final Practice
Replies: 3
Views: 72

Re: Final Practice

I'm not 100% sure, but you could also probably check the Test Bank at the SAC to see if they have any old finals.
by Eileen Si 1G
Wed Nov 27, 2019 11:20 pm
Forum: Lewis Acids & Bases
Topic: Conjugates
Replies: 3
Views: 21

Conjugates

What is the relation between electronegativity and strong/or weak acids? Also, can electronegativity be used to determine whether a base is strong or weak, or is it just relevant for acids?
by Eileen Si 1G
Wed Nov 27, 2019 11:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentate
Replies: 3
Views: 31

Polydentate

How do you determine whether a ligand is polydentate or not?
by Eileen Si 1G
Wed Nov 27, 2019 11:05 pm
Forum: Naming
Topic: Chelation
Replies: 2
Views: 23

Re: Chelation

Also, what are the effects of chelation, if there are any?
by Eileen Si 1G
Wed Nov 27, 2019 11:05 pm
Forum: Naming
Topic: Chelation
Replies: 2
Views: 23

Chelation

How do you know which ligands are capable of forming chelates, and what is the significance of chelation in relation to coordination compounds?
by Eileen Si 1G
Fri Nov 22, 2019 9:22 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: 3F.5
Replies: 4
Views: 32

Re: 3F.5

After drawing a Lewis structure for both of these molecules, you can see that the arrangement of the atoms in butanol allow for a Hydrogen bond between H and N, which is a stronger interaction force than just the dipole-dipole interaction forces and London dispersion forces in diethyl ether. As a re...
by Eileen Si 1G
Fri Nov 22, 2019 9:16 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Homework 3F1
Replies: 4
Views: 41

Re: Homework 3F1

H2SeO4 is also polar, so it will have dipole-dipole interactions as well as London dispersion forces.
by Eileen Si 1G
Wed Nov 20, 2019 9:01 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Melting Point
Replies: 3
Views: 38

Melting Point

How is the polarizing power of cations and melting point related? In other words, does having a higher polarizing power indicate a higher or lower melting point?
by Eileen Si 1G
Wed Nov 20, 2019 2:17 pm
Forum: Dipole Moments
Topic: Identifying Induced-Dipole
Replies: 3
Views: 29

Identifying Induced-Dipole

How can you identify the difference between a dipole moment versus an induced dipole moment? Is it possible to tell by looking at the Lewis structures, or do you have to use another method to figure if it's dipole or induced-dipole?
by Eileen Si 1G
Mon Nov 18, 2019 5:31 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 7
Views: 57

Test 2

Does anyone know if it will matter whether or not we say "bent" or "angular" to describe certain VSEPR models on the test?
by Eileen Si 1G
Mon Nov 18, 2019 3:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2
Replies: 2
Views: 48

Re: Test 2

So will test 2 include Focus 2D from Outline 3 (Chemical Bonds), or will it include everything afterwards?
by Eileen Si 1G
Sat Nov 16, 2019 11:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Homework 2E.7 b)
Replies: 1
Views: 33

Homework 2E.7 b)

For part b of 2E.7, why is it that there is only one bond angle between S, O, and Cl? I understand that there is one lone electron, but where would this extra single electron go in a Lewis structure model for SOCl if a Lewis structure for this molecule is even possible?
by Eileen Si 1G
Thu Nov 14, 2019 11:53 am
Forum: Administrative Questions and Class Announcements
Topic: Extra Credit?
Replies: 6
Views: 80

Re: Extra Credit?

Test 2 should cover topics ranging from Lewis structures, intermolecular forces, and the VSEPR Model. Hopefully I'm not missing anything!
by Eileen Si 1G
Thu Nov 14, 2019 11:50 am
Forum: Administrative Questions and Class Announcements
Topic: Test #2
Replies: 4
Views: 28

Test #2

Will any of the topics that we were tested on the midterm also be included in Test 2?
by Eileen Si 1G
Thu Nov 14, 2019 11:48 am
Forum: Hybridization
Topic: Lone Pairs
Replies: 3
Views: 46

Lone Pairs

How can you determine whether a lone pair is in a hybridized orbital? Like for NH3, N is sp3, but why is the lone pair on N not in an unhybridized p orbital instead?
by Eileen Si 1G
Thu Nov 14, 2019 11:42 am
Forum: Lewis Structures
Topic: Test Questions regarding Electronegativity
Replies: 2
Views: 29

Re: Test Questions regarding Electronegativity

Adding on to what the person above me said, I think he will provide us with the chart also because we haven't been taught yet to calculate the electronegativity values for each element and most of these values have already been found in outside professional labs.
by Eileen Si 1G
Thu Nov 14, 2019 11:37 am
Forum: Sigma & Pi Bonds
Topic: hybridization
Replies: 3
Views: 45

Re: hybridization

Hybridization describes the process where atomic orbitals fuse together in order to form new hybrid orbitals. To determine hybridization, you have to look at the number of atoms attached to the central atom and add it to the number of lone pairs. If the answer is 4, then the atom is sp3, if the answ...
by Eileen Si 1G
Sun Nov 10, 2019 3:40 am
Forum: Bond Lengths & Energies
Topic: Dissociation Energy
Replies: 9
Views: 35

Dissociation Energy

Why are dissociation energies always positive? Is energy released or gained when a bond is broken?
by Eileen Si 1G
Sun Nov 10, 2019 3:38 am
Forum: Bond Lengths & Energies
Topic: Bond Lengths
Replies: 3
Views: 29

Re: Bond Lengths

Triple bonds are the shortest and strongest, and single bonds are the longest and weakest, with double bonds being somewhere in the middle of single and triple bonds. This is because single bonds are more easily broken and likely to be involved in a reaction, while stronger bonds are harder to break...
by Eileen Si 1G
Sun Nov 10, 2019 3:35 am
Forum: Dipole Moments
Topic: Polarity
Replies: 3
Views: 23

Polarity

How do dipole moments determine polarity, like whether a covalent bond is polar or nonpolar?
by Eileen Si 1G
Sun Nov 10, 2019 3:32 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability
Replies: 4
Views: 21

Polarisability

How can you tell whether one element is more polarizable than another? Also, is there a difference between an element that has more polarizing power vs. an element that is the most polarizable?
by Eileen Si 1G
Sun Nov 10, 2019 3:29 am
Forum: Electronegativity
Topic: Ionization Energy vs. Electronegativity
Replies: 9
Views: 52

Ionization Energy vs. Electronegativity

What is the difference between ionization energy and electronegativity? If so, is there a way to differentiate between the two just by looking at the periodic table?
by Eileen Si 1G
Tue Nov 05, 2019 9:45 pm
Forum: Electronegativity
Topic: Ionization Energy
Replies: 3
Views: 27

Ionization Energy

Why does Oxygen have a lower ionization energy than Nitrogen? Are there are other elements that are special in the respect that they have lower ionization energies than the element to their right?
by Eileen Si 1G
Tue Oct 29, 2019 2:01 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 28
Views: 184

Re: Midterm

The midterm should cover the topics of Fundamentals, Quantum World, and some of Chemical Bonds.
by Eileen Si 1G
Tue Oct 29, 2019 1:57 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 10
Views: 95

Re: Midterm

I think that we need a blue book, since it is an official midterm, as well as a scientific calculator for basic calculations. Other than that, some extra pens would be good to have on hand too. And I haven't heard anything about the midterm locations yet, so he will probably be sending out an email ...
by Eileen Si 1G
Tue Oct 29, 2019 1:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Topics
Replies: 5
Views: 55

Re: Midterm Topics

The Midterm should cover topics from Fundamentals, the Quantum World, and some of Chemical Bonds as well.
by Eileen Si 1G
Tue Oct 29, 2019 1:49 pm
Forum: Administrative Questions and Class Announcements
Topic: posting on chemistry community
Replies: 11
Views: 140

Re: posting on chemistry community

The deadline is by 11:59pm Sunday night
by Eileen Si 1G
Tue Oct 29, 2019 1:37 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Topics
Replies: 1
Views: 23

Midterm Topics

Does anyone know if the Fundamentals topic that we covered for the first test will be included on the midterm? Or will the midterm just be testing us on the Quantum World and Chemical Bonds?
by Eileen Si 1G
Tue Oct 29, 2019 1:22 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2A.21
Replies: 1
Views: 26

Homework 2A.21

For part d of this question, it asks what the ground-state electron configuration is for Ag+. I thought it was [Kr]4d^8 5s^2, but the solutions manual says that it is [Kr]4d^10. Is this because the two electrons from the 5s shell go to the 4d shell? And if so, why does this happen?
by Eileen Si 1G
Fri Oct 25, 2019 6:31 pm
Forum: Sigma & Pi Bonds
Topic: Difference between Sigma & Pi
Replies: 5
Views: 59

Difference between Sigma & Pi

What is the difference between sigma and pi bonds? Are there ever cases where both of them will be present at the same time in the same molecule?
by Eileen Si 1G
Fri Oct 25, 2019 6:30 pm
Forum: Sigma & Pi Bonds
Topic: Significance of Sigma and Pi Bonds
Replies: 3
Views: 38

Re: Significance of Sigma and Pi Bonds

Sigma and pi bonds are significant because they can be utilized to predict how molecules behave by providing you with the shape of the molecule.
by Eileen Si 1G
Fri Oct 25, 2019 6:23 pm
Forum: Lewis Structures
Topic: Anion
Replies: 7
Views: 59

Re: Anion

For an anion, you would add the negative charge to the number of electrons in order to figure out the total number of electrons to draw in the Lewis structure. Moreover, you can then draw brackets around the whole Lewis structure and write the negative charge outside the top right corner of the brac...
by Eileen Si 1G
Fri Oct 25, 2019 6:10 pm
Forum: Resonance Structures
Topic: Delocalized
Replies: 4
Views: 34

Re: Delocalized

When an electron is delocalized, it is able to be rearranged into different molecular structures, because it isn't bound to just one atom or ion. As a result, there is resonance and you can have multiple structure with bonds in different locations.
by Eileen Si 1G
Fri Oct 25, 2019 2:36 pm
Forum: Ionic & Covalent Bonds
Topic: Identifying Ionic vs Covalent
Replies: 7
Views: 54

Identifying Ionic vs Covalent

How do you identify whether a bond is ionic or covalent (polar or nonpolar)? And is it possible to tell by just looking at a molecular formula?
by Eileen Si 1G
Fri Oct 25, 2019 2:22 pm
Forum: Octet Exceptions
Topic: Determining Exceptions
Replies: 3
Views: 34

Determining Exceptions

How would you determine whether or not an element is an exception to the octet rule? Are there any indicators of octet rule exceptions, or do you just have to memorize which elements are an exception?
by Eileen Si 1G
Sun Oct 20, 2019 3:01 pm
Forum: Quantum Numbers and The H-Atom
Topic: Lyman and Balmer
Replies: 3
Views: 41

Re: Lyman and Balmer

In Lyman series, the wavelengths range from 10 nm to 400 nm, because they are associated with UV light, while in the Balmer series, the wavelengths range from 700 nm to 400 nm, because they are associated with visible light. Moreover, for Lyman series, electrons go from higher to lower energy to n=1...
by Eileen Si 1G
Sun Oct 20, 2019 2:40 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What is Z eff e?
Replies: 3
Views: 29

Re: What is Z eff e?

Zeff e means the effective nuclear charge of an electron. In order words, it is the net charge that an electron experiences in multi-electron atoms.
by Eileen Si 1G
Sun Oct 20, 2019 2:23 pm
Forum: Quantum Numbers and The H-Atom
Topic: Spin States
Replies: 4
Views: 30

Spin States

Do we have to know how to find the spin states of an electron? And if so, how exactly do we do that?
by Eileen Si 1G
Sun Oct 20, 2019 2:12 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Wave Function vs Orbital vs Subshell vs Shell
Replies: 3
Views: 27

Re: Wave Function vs Orbital vs Subshell vs Shell

A wave function is a mathematical description that tells you where to find an electron. An orbital is used to describe exactly where the electrons are, like in s- or p-. A subshell is located within a shell, and has a value of l. A shell is used to describe the energy level where electrons reside, a...
by Eileen Si 1G
Sat Oct 19, 2019 3:45 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Geometric description of shell, subshell, and orbitals
Replies: 2
Views: 49

Re: Geometric description of shell, subshell, and orbitals

A shell is the pathway that an electron follows as it orbits the nucleus, so if drawn, it may just be represented by a simple circle around a nucleus. Orbitals can be illustrated geometrically depending on whether it is categorized as s, p, d, or f. s- orbitals have no nodes and are symmetrical, so ...
by Eileen Si 1G
Sat Oct 19, 2019 3:17 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals vs. Shells
Replies: 5
Views: 43

Orbitals vs. Shells

What is the difference between an orbital and a shell?
by Eileen Si 1G
Fri Oct 11, 2019 5:02 pm
Forum: DeBroglie Equation
Topic: When to use DeBroglie Equation
Replies: 16
Views: 159

Re: When to use DeBroglie Equation

You cannot use the DeBroglie Equation for light, but for particles that have momentum or wavelike properties (a wavelength).
by Eileen Si 1G
Fri Oct 11, 2019 4:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Negative Electrons vs Positive Nucleus
Replies: 2
Views: 45

Negative Electrons vs Positive Nucleus

If electrons have a negative charge and the nucleus of an atom is positive, why don't electrons collapse down to the nucleus? I understand that electrons have wavelike properties, but how does this account for the fact that electrons don't collapse down to the nucleus?
by Eileen Si 1G
Fri Oct 11, 2019 4:47 pm
Forum: Photoelectric Effect
Topic: Wavelengths?
Replies: 8
Views: 71

Re: Wavelengths?

There is no correlation between amplitude and frequency. Amplitude is just how high or low a wave can go, which exists independently of the frequency of a wave, which is the number of waves in a given time.
by Eileen Si 1G
Fri Oct 11, 2019 4:31 pm
Forum: Properties of Light
Topic: Quanta vs Photon
Replies: 4
Views: 34

Quanta vs Photon

What is the difference between quanta and photons? To my understanding, both can be used to quantify light, but how are they different?
by Eileen Si 1G
Fri Oct 11, 2019 4:25 pm
Forum: Properties of Light
Topic: Electric vs Magnetic Fields
Replies: 2
Views: 25

Electric vs Magnetic Fields

If electromagnetic radiation involves both electric and magnetic fields and electric fields interact with charged particles like electrons, what do magnetic fields do? Do they also have a specific interaction with particles and if so, how do they affect them?
by Eileen Si 1G
Fri Oct 11, 2019 10:39 am
Forum: Properties of Light
Topic: Amplitude
Replies: 12
Views: 102

Amplitude

I understand that the wavelength and frequency of a wave share an inverse relationship with each other, but does amplitude have anything to do with this relationship as well? In other words, what is the relationship between amplitude and wavelength and amplitude and frequency?
by Eileen Si 1G
Sun Oct 06, 2019 1:30 pm
Forum: Empirical & Molecular Formulas
Topic: Polyatomic Ions
Replies: 1
Views: 31

Re: Polyatomic Ions

I do believe that there will be a formula sheet given for the test that might include polyatomic ions and their charges, but just to be safe, I would review them beforehand.
by Eileen Si 1G
Sun Oct 06, 2019 1:19 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E.15
Replies: 4
Views: 57

Re: E.15

Even though they don't explicitly include S in M(OH)2, the sulfide they are talking about in this problem is just given information that is needed to calculate the final molar mass of the metal. For example, the molar mass of (OH)2 is 34.02 g.mol-1. By subtracting the molar mass of (OH)2 is 34.02 g....
by Eileen Si 1G
Sun Oct 06, 2019 12:30 pm
Forum: Administrative Questions and Class Announcements
Topic: Homework Grading
Replies: 1
Views: 37

Homework Grading

Hi! Does anyone know if we will get our homework back from the TAs, and whether or not it will be graded with comments and such?
by Eileen Si 1G
Sun Oct 06, 2019 12:21 pm
Forum: Administrative Questions and Class Announcements
Topic: Chemistry Community Posts due date?
Replies: 3
Views: 62

Re: Chemistry Community Posts due date?

Yes, the Chemistry Community posts are due on Sunday by midnight at the end of each week!
by Eileen Si 1G
Sun Oct 06, 2019 12:19 pm
Forum: Administrative Questions and Class Announcements
Topic: Frequency of posting
Replies: 2
Views: 29

Re: Frequency of posting

They are due on Sunday by midnight at the end of each week.
by Eileen Si 1G
Sun Oct 06, 2019 12:13 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: homework e9
Replies: 1
Views: 47

Re: homework e9

Hi! In order to find the formula for magnesium sulfate heptahydrate, you need to look at a periodic table and find the atomic symbol for each element. For example, magnesium is Mg; sulfate is SO4 because it is an ion and not just a singular element on the period table. (If you Google sulfate, the fo...

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