Search found 101 matches
- Sat Mar 14, 2020 7:36 pm
- Forum: General Science Questions
- Topic: Final Content
- Replies: 5
- Views: 476
Re: Final Content
i actually do think that there will be hw questions on the exam! it's on the syllabus that the final will include hw questions, and i don't think that is going to change just because it's online.
- Sat Mar 14, 2020 7:34 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=qP
- Replies: 3
- Views: 445
Re: q=qP
this is especially useful to derive the equation delta G = delta H + w !!
- Sat Mar 14, 2020 7:30 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Is pH normally taken at equilibrium concentrations?
- Replies: 7
- Views: 722
Re: Is pH normally taken at equilibrium concentrations?
i think the problem will specify if the pH is at the initial or equilibrium state of the solution, because you could put that H+ concentration at either point when making your ICE table
- Sat Mar 14, 2020 7:27 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Conjugate Seesaw
- Replies: 5
- Views: 448
Re: Conjugate Seesaw
Ami is correct! The conjugate seesaw means that a weak acid will have a strong conjugate base
- Sat Mar 14, 2020 7:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Cvm/Cpm
- Replies: 3
- Views: 409
Re: Cvm/Cpm
3/2R and 5/2R are used for monoatomic or diatomic gases like N(g) or O2(g)
- Sun Mar 08, 2020 11:11 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: intermediates
- Replies: 5
- Views: 401
intermediates
will we have to come up with intermediates between two rxns, or will they be given to us? and if we have to make them up on our own, will multiple answers be acceptable?
- Sun Mar 08, 2020 11:09 am
- Forum: General Rate Laws
- Topic: integrated rate laws
- Replies: 7
- Views: 470
integrated rate laws
what is the difference between a rate law and an integrated rate law?
- Sun Mar 08, 2020 11:07 am
- Forum: General Rate Laws
- Topic: slow step
- Replies: 4
- Views: 350
slow step
how can you tell which step in a rxn is the rate-determining step/slow step? i get it by looking at a graph or something, but what if you only have the rxn in front of you?
- Sun Mar 08, 2020 11:05 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Pre-equilibrium help
- Replies: 1
- Views: 262
Re: Pre-equilibrium help
i learned a lot by watching this video: https://www.youtube.com/watch?v=irJ4ANrUXPI
he only mentions a little about pre-equilibrium, but i think overall, you will understand the most important aspects of kinetics!
he only mentions a little about pre-equilibrium, but i think overall, you will understand the most important aspects of kinetics!
- Sun Mar 08, 2020 11:00 am
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Checking Answers
- Replies: 3
- Views: 373
Re: Checking Answers
the book doesn't really mention any other ways to check your answers, so i don't think we will have to know that
- Sun Mar 08, 2020 10:58 am
- Forum: General Rate Laws
- Topic: Rate law
- Replies: 3
- Views: 330
Re: Rate law
i think it would be most appropriate to specify rate of consumption/production of A when you are dealing with multiple rate laws in one problem, or the question specifically asks you to specify
- Sun Mar 01, 2020 10:36 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: standard electrode potentials
- Replies: 1
- Views: 174
standard electrode potentials
for test #2, will we receive a list of all the standard electrode potentials needed along with the regular periodic table/equation sheet? kind of similar to the midterm?
- Sun Mar 01, 2020 10:34 am
- Forum: Balancing Redox Reactions
- Topic: Oxidation State/Number in General
- Replies: 2
- Views: 198
Re: Oxidation State/Number in General
i'm pretty sure this has to do with the electronegativity of the element, because some elements in compounds are more likely to attract electrons and have more stable/consistent oxidation states, while something like cardon can be a little more flexible.
- Sun Mar 01, 2020 10:32 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: The sign of ∆Gº
- Replies: 2
- Views: 325
Re: The sign of ∆Gº
i think this is referring to the equation ΔG=ΔG∘+RTlnQ
- Sun Mar 01, 2020 10:28 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Stronger Reducing Agent
- Replies: 2
- Views: 222
Re: Stronger Reducing Agent
for the ones with different oxidation states, i think you would have to think about the context of the rxn that you're using. if you write out the rxn you can calculate the oxidation state of Fe and go from there.
- Sun Mar 01, 2020 10:26 am
- Forum: Balancing Redox Reactions
- Topic: Redox Reactions and Acid/Base Reactions
- Replies: 9
- Views: 755
Re: Redox Reactions and Acid/Base Reactions
redox rxns that aren't acid/base rxns would be like the oxidation of iron: Fe + O2 --> Fe2O3
- Sun Mar 01, 2020 10:23 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6.N3 (a)
- Replies: 4
- Views: 375
Re: 6.N3 (a)
i think you're supposed to calculate n by the number of electrons that need to be transferred in the rxn. so you would have to write out the half-rxns of the cathode and anode, and see that only 1 electron is transferred and therefore n = 1
- Sun Feb 23, 2020 11:22 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: adding/subtracting half-redox rxns
- Replies: 4
- Views: 337
adding/subtracting half-redox rxns
when we combine half-redox rxn like in Hess's law, why can't we also add together the E as if it was delta H?
- Sun Feb 23, 2020 11:19 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: test 2 material clarification
- Replies: 10
- Views: 681
test 2 material clarification
will gibbs free energy be on test 2? specifically, the equations where we connect delta G and Q/K?
- Sun Feb 23, 2020 11:18 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: EMF and Q
- Replies: 1
- Views: 128
EMF and Q
can someone explain the connection between having a negative or positive EMF and Q? i know that having more reactants in a rxn will make it more spontaneous bc the rxn will want to shift toward products, but how is this related to the potential difference in the cell?
- Sun Feb 23, 2020 11:14 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic Cell emf
- Replies: 3
- Views: 266
Re: Galvanic Cell emf
how would a galvanic cell have a negative emf?
- Sun Feb 23, 2020 11:11 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Galvanic/Voltaic cells
- Replies: 3
- Views: 281
Re: Galvanic/Voltaic cells
is there also a real-life example for other parts of the galvanic cell, such as the salt bridge?
- Sun Feb 23, 2020 11:09 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n
- Replies: 13
- Views: 781
Re: n
I believe 8.134 is the number used as the gas constant R! For n, we want to use the number of moles in the rxn
- Sun Feb 16, 2020 2:24 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Work and Gibbs Free Energy
- Replies: 3
- Views: 189
Re: Work and Gibbs Free Energy
i think temperature and pressure have to be constant, so that no energy is released as heat or entropy, but all used as work
- Sun Feb 16, 2020 2:22 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: endo/exo and temp
- Replies: 12
- Views: 1157
endo/exo and temp
why do exothermic reactions shift to reactants and endothermic reactions shift to products when there is an increase in temperature?
- Sun Feb 16, 2020 2:20 pm
- Forum: Balancing Redox Reactions
- Topic: oxidation states (6K.1)
- Replies: 2
- Views: 93
oxidation states (6K.1)
how do i know the oxidation states of elements in compounds?
for example, in 6K.1, it says that C is oxidized from -2 to 1- in C2H5OH --> C2H4O
for example, in 6K.1, it says that C is oxidized from -2 to 1- in C2H5OH --> C2H4O
- Sun Feb 16, 2020 2:17 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: delta G and K
- Replies: 2
- Views: 107
delta G and K
will the equation to calculate K using delta G be on the next exam? (Test 2??)
- Sun Feb 16, 2020 2:16 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: 5.55
- Replies: 4
- Views: 432
5.55
A reaction used in the production of gaseous fuels from coal, which is mainly carbon, is C(s) + H2O(g) <--> CO(g) + H2(g). (a) Evaluate K At 900 K, given that the standard Gibbs free energies of formation of CO(g) and H2O(g) at 900 K are 2191.28 kJ/mol and 2198.08 kJ/mol, respectively. (b) A sample ...
- Sun Feb 16, 2020 2:13 pm
- Forum: Balancing Redox Reactions
- Topic: 6K.1
- Replies: 1
- Views: 134
6K.1
The following redox reaction is used in acidic solution in the Breathalyzer test to determine the level of alcohol in blood: H+(aq) + Cr2O7 2-(aq) + C2H5OH(aq) <--> Cr3+(q) + C2H4O(aq) + H2O(l) Identify the elements undergoing oxidation or reduction and indicate their initial and final oxidation num...
- Sun Feb 09, 2020 12:06 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Calculating q when U is not 0
- Replies: 1
- Views: 43
Re: Calculating q when U is not 0
i think the main equation for q is q = n.C.deltaT where C is the heat capacity of the substance you are heating and n can be either grams or moles
- Sun Feb 09, 2020 12:05 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4F.17
- Replies: 1
- Views: 69
4F.17
in the solutions manual, there are three steps to solve this equation: 1. calculate delta S for heat reactants to 100 degrees celsius 2. calculate delta S for the vaporization of H2 at 100 degrees celsius 3. calculate delta S for the rxn when it cools back down to 85 degrees why is it necessary for ...
- Sun Feb 09, 2020 12:01 pm
- Forum: Phase Changes & Related Calculations
- Topic: 4.23
- Replies: 1
- Views: 107
4.23
in this problem, we have to use the equation E = hc/λ and calculate the number of photons needed for the rxn
will we have to know this and other quantum equations for the midterm?
will we have to know this and other quantum equations for the midterm?
- Sun Feb 09, 2020 11:57 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: constant p/v
- Replies: 1
- Views: 86
constant p/v
does anyone know what equations to use when there is the condition that the system is at constant pressure/constant volume? i'm looking for equations related to q, w, delta U, and entropy
- Sun Feb 09, 2020 11:53 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 4I.5
- Replies: 4
- Views: 158
4I.5
Suppose that 50.0 g of water at 20.0 degrees Celsius is mixed with 65.0 g of water at 50.0 degrees Celsius at constant atmospheric pressure in a thermally insulated vessel. Calculate Delta S and Delta S(total) for the process. in the solutions manual, the first step is to assume there is no change i...
- Sun Feb 09, 2020 11:49 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4D.23
- Replies: 2
- Views: 196
4D.23
Calculate the standard enthalpy of formation of dinitrogen pentoxide from the following data: 2 NO(g) + O2(g) --> 2 NO2(g); delta H° = -114.1 kJ 4 NO2(g) + O2(g) --> 2 N2O5(g); delta H° = -110.2 kJ and from the standard enthalpy of formation of nitric oxide, NO (see Appendix 2A). how do i calculate ...
- Sun Feb 02, 2020 4:10 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Difference between delta H and q
- Replies: 2
- Views: 110
Re: Difference between delta H and q
when a system is at constant pressure, q = delta H because the only energy being released is through heat
- Sun Feb 02, 2020 4:06 pm
- Forum: Calculating Work of Expansion
- Topic: Reversible Processes
- Replies: 3
- Views: 129
Re: Reversible Processes
i think it will be given in the problem if the rxn is reversible or not
- Sun Feb 02, 2020 4:03 pm
- Forum: Calculating Work of Expansion
- Topic: 4B.9
- Replies: 3
- Views: 151
Re: 4B.9
no, we didn't go over adiabatic processes in class
i think for that question, we are just supposed to know that it's a closed system
i think for that question, we are just supposed to know that it's a closed system
- Sun Feb 02, 2020 4:02 pm
- Forum: Calculating Work of Expansion
- Topic: Hw 4A.13
- Replies: 2
- Views: 117
Re: Hw 4A.13
so in order to calculate delta U, we use the equation delta U = q(v) because it is at a constant volume so there is no work done so we need to figure out the q(rxn) by using the equaiton q(rxn/system) = q(surroundings) where the surroundings is the calorimeter first we need to figure out the specifi...
- Sun Feb 02, 2020 3:46 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: delta U = delta H - P delta V
- Replies: 3
- Views: 153
Re: delta U = delta H - P delta V
yes!
the change in internal energy (delta U) is usually calculated as heat (q) + work (w), but at constant pressure, q = delta H and w = -P(deltaV)
the change in internal energy (delta U) is usually calculated as heat (q) + work (w), but at constant pressure, q = delta H and w = -P(deltaV)
- Sun Jan 19, 2020 3:07 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc from K
- Replies: 3
- Views: 117
Re: Kc from K
do you know if K will mean Kp on the exam too? or will it explicitly state if we should calculate Kc or Kp?
- Sun Jan 19, 2020 3:05 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Writing acid and base equations for test 1?
- Replies: 1
- Views: 145
Re: Writing acid and base equations for test 1?
i think it's best to be prepared to write equations for acids and bases. if you know how to tell which compounds are acids and which are bases, then you can determine whether H30+ or OH- is produced (the trick is that acids give off a proton aka produced H3O+ and bases accept a proton aka produce OH...
- Sun Jan 19, 2020 3:01 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Volume and pressure
- Replies: 4
- Views: 164
Re: Volume and pressure
volume and pressure have an inverse relationship, so a decrease in volume = increase in pressure and an increase in volume = decrease in pressure
- Sun Jan 19, 2020 2:59 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: autoprotolysis
- Replies: 5
- Views: 152
Re: autoprotolysis
Kw basically means the ratio of products/reactants in the breakdown of water (2H2O <--> H3O+ + OH-)
- Sun Jan 19, 2020 2:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Change in Volume?
- Replies: 3
- Views: 125
Re: Change in Volume?
a change in volume doesn't affect K in the long run, only temperature does
- Sun Jan 12, 2020 1:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Comparing K Values
- Replies: 4
- Views: 241
Re: Comparing K Values
i think being more thermodynamically stable means that the equation's K value is closer to 1 (meaning that the products and reactants have equal values at equilibrium)
- Sun Jan 12, 2020 1:18 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: ICE vs Normal Concentrations
- Replies: 5
- Views: 170
Re: ICE vs Normal Concentrations
I would say you should bring out the ICE boxes when the question makes an effort to distinguish the initial concentrations of R/P and their equilibrium concentrations
- Sun Jan 12, 2020 1:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5H.1
- Replies: 2
- Views: 123
Re: 5H.1
for these questions, use the morality notation of brackets [] to represent concentration. 1. write K = 2. write [products]/[reactants] and use the coefficient in the equation as an exponent 3. do not write elements or compounds that are solid (s) or liquid (l) for example, in 5H.1 a) N2 +3H2 <--> 2N...
- Sun Jan 12, 2020 1:09 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Concentrations and the K value.
- Replies: 7
- Views: 411
Re: Concentrations and the K value.
I think it's because the coefficients in the reaction are representative of the molar ratio in the reaction, and the K value is basically a ration of the products/reactants by their concentration
- Sun Jan 12, 2020 1:08 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium and Limiting Reagent
- Replies: 2
- Views: 146
Re: Equilibrium and Limiting Reagent
I don't really think the two will ever be connected in a problem because in limiting reactant questions we are trying to calculate the amount of product that can form by the reactants being fully used in the reaction. But in equilibrium question, we look at both the reaction from reactants to produc...
- Sat Dec 07, 2019 4:57 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: homework question 6C.17
- Replies: 1
- Views: 63
homework question 6C.17
Which is the stronger base, the hypobromite ion, BrO2, or morphine, C17H19O3N? Justify your answer.
for 6C.17, the solutions manual uses the pKb of each base to determine which is stronger. is it possible to tell which is a stronger base without using this calculation?
for 6C.17, the solutions manual uses the pKb of each base to determine which is stronger. is it possible to tell which is a stronger base without using this calculation?
- Sat Dec 07, 2019 4:54 pm
- Forum: Lewis Acids & Bases
- Topic: homework question 6A.17
- Replies: 1
- Views: 171
homework question 6A.17
for this question, how do i know that As2O3 and Bi2O3 are amphteric?
State whether the following oxides are acidic, basic, or amphoteric: (a) BaO; (b) SO3; (c) As2O3; (d) Bi2O3.
State whether the following oxides are acidic, basic, or amphoteric: (a) BaO; (b) SO3; (c) As2O3; (d) Bi2O3.
- Sat Dec 07, 2019 4:52 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: homework question 6D.11
- Replies: 3
- Views: 227
homework question 6D.11
hi! i'm having trouble answering this question:
Decide whether an aqueous solution of each of the following salts has a pH equal to, greater than, or less than 7. Write a chemical equation to justify your answer. (a) NH4Br; (b) Na2CO3; (c) KF; (d) KBr; (e) AlCl3; (f) Cu(NO3)2.
Decide whether an aqueous solution of each of the following salts has a pH equal to, greater than, or less than 7. Write a chemical equation to justify your answer. (a) NH4Br; (b) Na2CO3; (c) KF; (d) KBr; (e) AlCl3; (f) Cu(NO3)2.
- Sat Dec 07, 2019 4:48 pm
- Forum: Biological Examples
- Topic: structures and formula for biological compounds
- Replies: 1
- Views: 81
structures and formula for biological compounds
hi! in the past exam questions review for the final, Lavelle went over a question that asked us to draw the structure of urea, and we also used cisplatin for another question. should we know how to draw all structures for the other biological coordination compounds as well? (myoglobin, hemoglobin, v...
- Sat Dec 07, 2019 4:44 pm
- Forum: Industrial Examples
- Topic: what examples should we know?
- Replies: 6
- Views: 1284
what examples should we know?
what examples of coordination compounds with industrial importance should we know for the final?
- Sun Dec 01, 2019 9:24 am
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Number
- Replies: 2
- Views: 230
Re: Coordination Number
The coordination number of an atom in a molecule is the number of atoms bonded to the atom. For Cu+, it would simply be the possible amount of atoms that it could bond to.
- Sun Dec 01, 2019 9:22 am
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 3
- Views: 372
Re: Naming Coordination Compounds
1. When naming a complex ion, the ligands are named before the metal ion. 2. Write the names of the ligands in the following order: neutral, negative, positive. If there are multiple ligands of the same charge type, they are named in alphabetical order. (Numerical prefixes do not affect the order.) ...
- Sun Dec 01, 2019 9:14 am
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: 6c.21
- Replies: 1
- Views: 80
Re: 6c.21
i think it would be more useful to look at the concentration of H atoms rather than the electronegativity to determine which is the weaker acid. acetic acid is considered weaker because it doesn't dissociate in solution as well as formic acid
- Sun Dec 01, 2019 9:11 am
- Forum: Lewis Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 4
- Views: 317
Re: Lewis vs Bronsted
yes, bronsted acids are also lewis acids. when an acid loses a proton, it gains a lone pair
- Sun Dec 01, 2019 9:10 am
- Forum: Conjugate Acids & Bases
- Topic: Strength of Conjugate Acids and Bases
- Replies: 3
- Views: 255
Re: Strength of Conjugate Acids and Bases
strong acids are completely deprotonated in water, and donates that proton so easily to the conjugate base which means that there's no need for the conjugate base to have any pull on the proton, thus making it weak
- Sat Nov 23, 2019 9:52 am
- Forum: Biological Examples
- Topic: Ringlike structures + chelating ligands
- Replies: 2
- Views: 86
Re: Ringlike structures + chelating ligands
also, because the ring-like structure of a chelating ligand will cause the cations to bind together really tightly, a compound with a lot of lone pair electrons will easily remove metals from a solution
- Sat Nov 23, 2019 9:43 am
- Forum: Lewis Acids & Bases
- Topic: bronsted and lewis acids
- Replies: 2
- Views: 158
bronsted and lewis acids
can an acid only be a bronsted acid or a lewis acid, or can they fall into both definitions? we learned that HCl, HBr, HNO3, and so on were bronsted acids because they loose a proton to a base, but can we also qualify any of them as a lewis acid (do they accept lone pair electrons?)
- Sat Nov 23, 2019 9:41 am
- Forum: Lewis Acids & Bases
- Topic: carboxyl group COOH
- Replies: 3
- Views: 253
carboxyl group COOH
how does the carboxyl group on C6H5COOH make the compound acidic?
- Sat Nov 23, 2019 9:33 am
- Forum: Naming
- Topic: oxidation states
- Replies: 2
- Views: 178
oxidation states
how do i find the oxidation state of a transition metal? so far, i've been confusing it with formal charge, but i know the two are different
- Sat Nov 23, 2019 9:31 am
- Forum: Biological Examples
- Topic: myoglobin and hemoglobin
- Replies: 3
- Views: 210
myoglobin and hemoglobin
what should we know about myoglobin and hemoglobin? Dr. Lavelle went through a lot of information about these two molecules, but i'm unsure of what parts are important for the final
- Fri Nov 15, 2019 11:16 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Homework Problem 2E.7
- Replies: 3
- Views: 215
Re: Homework Problem 2E.7
is writing "less than 109.5" an exceptable answer, or do we have to give a specific number?
- Fri Nov 15, 2019 11:13 am
- Forum: Sigma & Pi Bonds
- Topic: Hybridization
- Replies: 2
- Views: 196
Re: Hybridization
hybridization happens when electrons of a molecule are promoted. it doesn't happen for every molecule, only which if the overall change is toward lower energy with higher energy electrons
- Fri Nov 15, 2019 11:04 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: nonpolar molecules
- Replies: 5
- Views: 292
nonpolar molecules
do nonpolar covalent bond only have london dispersion forces? or can they have any of the other molecular forces?
- Fri Nov 15, 2019 11:01 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: induced dipoles
- Replies: 5
- Views: 351
induced dipoles
how do induced dipoles happen? and what are some examples of a dipole-induced dipole molecules?
- Fri Nov 15, 2019 10:57 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: tetrahedral/triangular pyramidal
- Replies: 2
- Views: 126
tetrahedral/triangular pyramidal
hi there! i was just wondering how to tell the difference between a tetrahedral molecule and a triangular pyramidal molecule, or if they can sometimes be interchangeable. I remember from the textbook that lone pairs are considered significant regions of high electron configurations just like bonds. ...
- Tue Nov 12, 2019 5:57 pm
- Forum: Octet Exceptions
- Topic: Octet Exceptions
- Replies: 2
- Views: 277
Re: Octet Exceptions
their valence shells are 1s and 2s, which don't even have enough orbitals for eight electrons. these elements are stable with just 2 (H, He) or 4 (Li, Be)
- Tue Nov 12, 2019 5:54 pm
- Forum: Resonance Structures
- Topic: ... hm.
- Replies: 3
- Views: 150
Re: ... hm.
resonance structures occur when you can shift the bonds in a molecule around. i think you're talking about created an entirely different lewis structure, which wouldn't be considered resonance.
- Tue Nov 12, 2019 5:52 pm
- 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.15
- Replies: 3
- Views: 124
Re: 3F.15
a higher boiling point means that the elements in the molecule are highly attracted to each other i.e. the intermolecular forces are strong. because AsF3 is a polar molecule (F, as the most electromagnetic element, creates a dipole) the bonds between the elements are stronger and will take more ener...
- Tue Nov 12, 2019 5:48 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Help of 3F.11
- Replies: 5
- Views: 185
Re: Help of 3F.11
i know i remember by the acronym FON (the elements fluorine, oxygen, and nitrogen)
- Tue Nov 12, 2019 5:47 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Test 2
- Replies: 3
- Views: 112
Re: Test 2
Alexa is right, it is everything we have learned up until the exam
- Sun Nov 03, 2019 6:14 pm
- Forum: Lewis Structures
- Topic: formal charge
- Replies: 6
- Views: 285
Re: formal charge
i don't think you have to check formal charge for every structure, just when the question asks you to. For drawing lewis structures, I think it's more important to fill up an octet than it is to have low formal charges
- Sun Nov 03, 2019 6:12 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron configuration
- Replies: 1
- Views: 78
Re: Electron configuration
4s is considered lower energy than 3d
- Sun Nov 03, 2019 6:10 pm
- Forum: Ionic & Covalent Bonds
- Topic: Lewis Acids and Bases
- Replies: 2
- Views: 164
Lewis Acids and Bases
What makes something a Lewis acid/base? And what do coordinate covalent bonds have to do with acid-base rxns?
- Sun Nov 03, 2019 6:08 pm
- Forum: Octet Exceptions
- Topic: Biological Impacts of Radicals
- Replies: 4
- Views: 162
Re: Biological Impacts of Radicals
radicals affect the body at a cellular level because they are very reactive and will react with DNA, causing it to mutate
- Sun Nov 03, 2019 6:06 pm
- Forum: Electronegativity
- Topic: Covalent Character and Polarizability
- Replies: 2
- Views: 317
Covalent Character and Polarizability
Hi! Could someone please explain the connection between polarizability and covalent character in an ionic bond? Also, does electronegativity play a role in a bond's covalent/ionic character as well?
- Sun Oct 27, 2019 9:05 am
- Forum: Properties of Light
- Topic: Rydberg Equation
- Replies: 3
- Views: 182
Re: Rydberg Equation
the Rydberg equation is usually used to calculate the wavelength of a spectral line, but in hw problems we've also used it to find the energy level n1 or n2 of a certain line. the only constant is the Rydberg constant, which is explained above, but there's also the energy levels n1 and n2, which cor...
- Sun Oct 27, 2019 9:00 am
- Forum: Lewis Structures
- Topic: Drawing Lewis Structure
- Replies: 6
- Views: 211
Re: Drawing Lewis Structure
since we've been drawing all of the lone pairs in class and in hw, it's safe to say that yes, you will have to draw those for the exam. however, i remember some teachers using a line instead of dots to represent lone pairs, so if you want to find alternate ways to draw your lewis structures just tal...
- Sun Oct 27, 2019 8:57 am
- Forum: SI Units, Unit Conversions
- Topic: Midterm
- Replies: 6
- Views: 360
Re: Midterm
yes, the midterm is cumulative, so we will have all the topics discussed in class up until the day before the exam. if you want to know what are popular topics/questions on the midterm, i would recommend finding old exams to practice or just look at. they have a lot available at sac, or a couple onl...
- Sun Oct 27, 2019 8:54 am
- Forum: Ionic & Covalent Bonds
- Topic: Explaining periodic trends
- Replies: 3
- Views: 181
Re: Explaining periodic trends
i think it's less about what factors are most important, and more about what factors are the strongest, i.e. what forces holds the bonds together the best. also, you have to think about how these factors are kind of like products of one another and are interrelated (for example, because of an increa...
- Sun Oct 27, 2019 8:51 am
- Forum: Ionic & Covalent Bonds
- Topic: hybrid/line structure
- Replies: 2
- Views: 84
Re: hybrid/line structure
from what I understand, you can substitute this kind of structure for the lewis structure at any time, because it's an organic compound, and this is just another way of representing the compound. I know he said we wouldn't be doing much o-chem this quarter, so I wouldn't worry about it
- Sat Oct 19, 2019 8:28 pm
- Forum: Properties of Electrons
- Topic: mass of electron, proton, neutron
- Replies: 7
- Views: 389
mass of electron, proton, neutron
hi! on some of the hw problems we've had to use the mass of an electron/proton/neutron in certain calculations, will it be necessary to memorize those values for an exam, or will they be on an equation sheet? thank you!
- Sat Oct 19, 2019 8:20 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: n, l, m
- Replies: 4
- Views: 179
Re: n, l, m
n, l, and m are all quantum numbers n = principle quantum number - it measures energy and size of an orbital, also called the "shell" - it has values of integers (0,1,2,3,4...) l = angular momentum quantum number - it measures shape of an orbital, called "subshell" - it has value...
- Sat Oct 19, 2019 8:15 pm
- Forum: DeBroglie Equation
- Topic: 1B #15
- Replies: 4
- Views: 183
1B #15
hi! would someone please walk me through their steps for this problem? The velocity of an electron that is emitted from a metallic surface by a photon is 3.63 e 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 frequen...
- Sat Oct 19, 2019 8:01 pm
- Forum: Properties of Electrons
- Topic: Conceptual vs. problem
- Replies: 2
- Views: 96
Re: Conceptual vs. problem
no, i don't think we have to know how these equations were derived for this class, because the math behind that is much more advanced than what we're supposed to know. just be sure you know the concepts behind each equation and how to apply it to problems!
- Sat Oct 19, 2019 8:00 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Easy Mnemonics for the 3 Principles!
- Replies: 1
- Views: 720
Re: Easy Mnemonics for the 3 Principles!
thank you, this is very helpful!
- Sat Oct 19, 2019 7:58 pm
- Forum: Properties of Electrons
- Topic: Electron structures
- Replies: 2
- Views: 123
Re: Electron structures
technically yes, i guess it doesn't really matter which space you put your first arrow bc it's in the same orbital/subshell, but i think it's best that you just fill it in from left to right just so it's less confusing that way!
- Sun Oct 13, 2019 2:56 pm
- Forum: Properties of Electrons
- Topic: Wavelength properties of electrons
- Replies: 4
- Views: 252
Re: Wavelength properties of electrons
hi there! i believe it is because the wavelength of macroscopic objects is just too small. if you look at the De Broglie equation, wavelength = h/mv, the larger the mass, the smaller the wavelength will be because planck's constant is divided by mass. when the wavelength is just that small, then the...
- Sun Oct 13, 2019 2:51 pm
- Forum: Student Social/Study Group
- Topic: Turning in Extra HW problems
- Replies: 10
- Views: 442
Re: Turning in Extra HW problems
absolutely it is most effective to do all the hw problems on the list! i think you get a more thorough understanding of the concept that way, and you feel more familiar with the calculations and equations.
- Sun Oct 13, 2019 2:47 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Best Way To Study?
- Replies: 56
- Views: 3524
Best Way To Study?
hi guys! my question is about what you all seem to find is the best studying strategy for this class. so far i've been watching youtube videos along with just taking notes during lecture and reading/doing hw problems from the textbook, but i'm curious to see what other methods people use to study th...
- Sun Oct 13, 2019 2:41 pm
- Forum: Photoelectric Effect
- Topic: Work Function
- Replies: 2
- Views: 111
Re: Work Function
hi there! the work function is the amount of energy needed to remove an electron from a metal surface i think more often than not it will be given in hw problems, but if there comes a time when you need to calculate it, it should be quite easy if you use the equation from lecture ( the work function...
- Tue Oct 08, 2019 11:30 am
- Forum: Empirical & Molecular Formulas
- Topic: empirical to molecular formula [ENDORSED]
- Replies: 9
- Views: 609
empirical to molecular formula [ENDORSED]
hi! so when you are trying to calculate the molecular formula and you are given the empirical formula and the mass of whatever compound, i know that you're supposed to calculate the molar mass from the empirical formula and find a ratio between the masses, then multiply by whatever number it comes o...
- Thu Oct 03, 2019 8:49 am
- Forum: Balancing Chemical Reactions
- Topic: Homework Problem M.9
- Replies: 2
- Views: 169
Re: Homework Problem M.9
basically, yes.
for net ionic equations, you want to take out the elements of which don't form a precipitate in the products. these are called "spectator ions", because they stay dissolved in the aqueous solution as both a reactant and a product.
for net ionic equations, you want to take out the elements of which don't form a precipitate in the products. these are called "spectator ions", because they stay dissolved in the aqueous solution as both a reactant and a product.
- Thu Oct 03, 2019 8:45 am
- Forum: Limiting Reactant Calculations
- Topic: Homework Question
- Replies: 3
- Views: 247
Re: Homework Question
hi there! if you balance the equation, i believe it actually comes out to 4 molecules of NH3 for 5 molecules of O2. 4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g) because of this, when you calculate moles of reactants, you must take into account the molar ratio of these molecules before deciding the limitin...
- Tue Oct 01, 2019 4:48 pm
- Forum: Limiting Reactant Calculations
- Topic: Question about E9 [ENDORSED]
- Replies: 3
- Views: 210
Re: Question about E9 [ENDORSED]
hi! even though formula writing isn't specifically mentioned in outline 1, i think it's implied that we should be able to write out formulas from symbols and vice versa, because one of the bullet points is to be able to "Write symbols for the elements, given their names, and vice versa". i...
- Tue Oct 01, 2019 4:34 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamentals: G#25
- Replies: 2
- Views: 116
Fundamentals: G#25
hey guys! i have a question for #25 in the G section for fundamentals. it's asking how many molecules will be present in 10. mL of the final solution after diluting 10. mL with a concentration of 0.10 mol L^-1 90 times. i remember a key concept was that moles stays the same during dilutions. does th...