Search found 94 matches

by Angela Patel 2J
Sat Feb 22, 2020 11:18 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: relevance of salt bridge
Replies: 4
Views: 8

Re: relevance of salt bridge

Does the porous disk/wall do the same thing as the salt bridge?
by Angela Patel 2J
Sat Feb 22, 2020 11:15 am
Forum: Balancing Redox Reactions
Topic: Oxidation Numbers
Replies: 4
Views: 11

Re: Oxidation Numbers

We know common oxidation numbers. For example oxygen always has an oxidation number of 2-. Hydrogen is typically +1. All group 1 metal cations have a charge of +1, etc. You can use these known oxidation numbers to find the oxidation numbers of other elements in compounds with these.
by Angela Patel 2J
Sat Feb 22, 2020 11:12 am
Forum: Balancing Redox Reactions
Topic: Cell Diagram
Replies: 1
Views: 5

Re: Cell Diagram

When the two compounds are in the same phase (for example both in aqueous solution) then you would use a comma. When they are in contact but are in different phases (like with a solid conductor and the metal in solution) you use a single vertical line.
by Angela Patel 2J
Sat Feb 22, 2020 11:09 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Purpose of Salt Bridge
Replies: 12
Views: 30

Re: Purpose of Salt Bridge

But the battery still dies, so when does the salt bridge stop working?
by Angela Patel 2J
Sat Feb 22, 2020 11:07 am
Forum: Balancing Redox Reactions
Topic: 6K.1
Replies: 2
Views: 10

Re: 6K.1

The oxidation state changes, but there are also a certain number of molecules. So for carbon, even though the oxidation state goes from 2- to 1-, there are 2 carbon molecules so this would involve 2 electrons.
by Angela Patel 2J
Wed Feb 12, 2020 4:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 4D.23
Replies: 2
Views: 13

Re: 4D.23

Because there are two moles of NO gas. Standard enthalpies of formation are given per mole, so you need to multiply each one by the number of moles when using the equation given on the formula sheet.
by Angela Patel 2J
Wed Feb 12, 2020 3:57 pm
Forum: Calculating Work of Expansion
Topic: 4A.3
Replies: 1
Views: 18

Re: 4A.3

I think it's possible. Lavelle went over the work formula w = pressure * area * distance so it is fair game for the midterm.
by Angela Patel 2J
Wed Feb 12, 2020 3:45 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Irreversible reactions and temperature
Replies: 3
Views: 45

Re: Irreversible reactions and temperature

It is possible to have a reaction where the temperature change is 0 but delta U is constant. Work and heat both affect temperature, so if their effects on temperature cancel out you could technically have a situation where there is no temp. change.
by Angela Patel 2J
Wed Feb 12, 2020 3:41 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: pizza rolls 5c
Replies: 2
Views: 17

Re: pizza rolls 5c

We can calculate entropy of vaporization at temperatures other than the boiling point. Just multiply the entropy of vaporization by the temperature (in Kelvin) and the # of moles of water.
by Angela Patel 2J
Wed Feb 12, 2020 3:39 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Adiabatic process
Replies: 3
Views: 27

Adiabatic process

For an adiabatic process, would the only change in temperature of the system be due to the amount of work done? Would the temperature change for an adiabatic process be less than the temperature change for a irreversible expansion? For example question 4.6 in the textbook, where it gives you a press...
by Angela Patel 2J
Fri Feb 07, 2020 11:18 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Equation
Replies: 3
Views: 22

Re: Equation

Leonardo Le Merle 1D wrote:What are we meant to use if it is not reversible expansion?


You can use the equation S = nRln(v1/v2) if the pressure is not constant.
by Angela Patel 2J
Fri Feb 07, 2020 6:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: why/how do molar gibbs free energies change?
Replies: 1
Views: 24

Re: why/how do molar gibbs free energies change?

I'm not 100% sure, but it probably has to do with changes in entropy. Different molecular compositions for a solution would probably change entropy (and therefore gibbs free energy) as there would be a different number of states. I'm guessing that for the midterm we don't have to understand this exa...
by Angela Patel 2J
Fri Feb 07, 2020 6:35 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Equation
Replies: 3
Views: 22

Re: Equation

For calculating delta S, you can substitute qrev for delta H. Remember that this is only true when there is constant pressure.
by Angela Patel 2J
Fri Feb 07, 2020 6:33 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Boltzmann Equation
Replies: 2
Views: 12

Re: Boltzmann Equation

The kB constant can be expressed in terms of the gas constant (8.314 J/K*mol) divided by avogadro's number.
by Angela Patel 2J
Fri Feb 07, 2020 6:32 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: GFE dividing by temp
Replies: 3
Views: 14

Re: GFE dividing by temp

Because - delta H / T is the change in entropy of the surroundings (discussed earlier in lecture today) and this makes the equation easier to simplify into something that only has one variable. This way we can define spontaneity of a process in terms of only gibbs free energy.
by Angela Patel 2J
Mon Feb 03, 2020 4:59 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: q and w
Replies: 10
Views: 49

Re: q and w

Along with the tricks mentioned above, you can also determine whether work will be positive or negative based on expansion. If the system is expanding outward, work will be negative (w = -P(delta V)). On the other hand, if it is expanding inward, work will be positive. Hope this helped! Yes, work w...
by Angela Patel 2J
Thu Jan 30, 2020 1:29 pm
Forum: Calculating Work of Expansion
Topic: 4A.3
Replies: 7
Views: 49

Re: 4A.3

Also, how would we know the sign of the internal energy?
by Angela Patel 2J
Thu Jan 30, 2020 1:28 pm
Forum: Calculating Work of Expansion
Topic: 4A.3
Replies: 7
Views: 49

Re: 4A.3

How do we know that the pressure is constant for this system?
by Angela Patel 2J
Wed Jan 29, 2020 5:09 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs. Boiling Water
Replies: 10
Views: 47

Re: Steam vs. Boiling Water

Basically, this is because steam has undergone a phase change from liquid to water vapor (vaporization). Vaporization requires a lot of energy. When steam touches your skin, it will release a lot of energy as it cools to form liquid water. Water, while at the same energy, does not have the same lat...
by Angela Patel 2J
Wed Jan 29, 2020 5:07 pm
Forum: Calculating Work of Expansion
Topic: Irreversible vs. Reversible Reactions
Replies: 6
Views: 44

Re: Irreversible vs. Reversible Reactions

During reversible reactions, products and reactants are always being made (going back and forth), while in irreversible reactions products can't revert back to what it was as a reactant. I also think that during reversible reactions, the system stays at thermodynamic equilibrium, and during irrever...
by Angela Patel 2J
Wed Jan 29, 2020 5:06 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q vs deltaH
Replies: 6
Views: 29

Re: q vs deltaH

why would q ever not be equal to delta H?
by Angela Patel 2J
Wed Jan 29, 2020 5:03 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: work equations
Replies: 5
Views: 34

Re: work equations

What about when we are calculating the change in internal energy in a system under constant pressure? Work is involved, do we always use the negative sign in the expression for work?
by Angela Patel 2J
Wed Jan 29, 2020 12:28 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Systems at equilibrium
Replies: 3
Views: 23

Re: Systems at equilibrium

We will discuss it more when we start talking about thermodynamics. For now, all we need to know is that there is a difference in the amount of work done depending on whether the gaseous system is under pressure or not.
by Angela Patel 2J
Wed Jan 29, 2020 12:26 pm
Forum: Ideal Gases
Topic: Temperature
Replies: 17
Views: 46

Re: Temperature

Is it ok to use either since we only care about the change in temperature? The change in temperature will be the same whether measured in kelvin or celsius.
by Angela Patel 2J
Thu Jan 23, 2020 10:56 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Stoichiometric Coefficients
Replies: 2
Views: 12

Re: Stoichiometric Coefficients

Yep, because that represents having two moles of that reactant or product!
by Angela Patel 2J
Thu Jan 23, 2020 10:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What do we need to know about titrations?
Replies: 2
Views: 16

Re: What do we need to know about titrations?

I would make sure to understand the concepts behind titrations, including why they are done. To remind you, titrations are used to determine the concentration of an acid or base in solution. An example would be an acid of unknown concentration that reacts with a base of known concentration. You woul...
by Angela Patel 2J
Thu Jan 23, 2020 10:51 pm
Forum: Phase Changes & Related Calculations
Topic: Work, reversible path
Replies: 2
Views: 19

Re: Work, reversible path

If the textbook is talking about chemical reactions specifically, it means that reversible reactions will involve the most work. This is because the reaction will reach equilibrium (meaning the rates of the forward and reverse reactions are constant). Because the molecules are constantly reacting wi...
by Angela Patel 2J
Thu Jan 23, 2020 10:47 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Molar concentration of H3O
Replies: 6
Views: 15

Re: Molar concentration of H3O

You would have to know the concentration of OH- if that was the only information you are given.
by Angela Patel 2J
Thu Jan 23, 2020 10:46 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs. Boiling Water
Replies: 10
Views: 47

Re: Steam vs. Boiling Water

Basically, this is because steam has undergone a phase change from liquid to water vapor (vaporization). Vaporization requires a lot of energy. When steam touches your skin, it will release a lot of energy as it cools to form liquid water. Water, while at the same energy, does not have the same late...
by Angela Patel 2J
Thu Jan 16, 2020 10:48 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use K and Kp
Replies: 12
Views: 36

Re: When to use K and Kp

What if you are given all gases, can you still use Kc? I know you can convert to Kp but why wouldn't we just use concentrations if they are given?
by Angela Patel 2J
Thu Jan 16, 2020 10:46 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb
Replies: 5
Views: 16

Re: Ka and Kb

So Ka would be calculated for a compound by studying its equilibrium concentrations as if it were an acid, and Kb would be calculated for the conjugate base of that acid and its reaction is what I'm getting. Like the example with NH3 and NH4+ we did in lecture.
by Angela Patel 2J
Wed Jan 15, 2020 10:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: solubility
Replies: 3
Views: 28

Re: solubility

For example for an acid, we can find how much will dissociate in water by making the ICE table and finding the equilibrium concentration of the hydronium ion
by Angela Patel 2J
Wed Jan 15, 2020 10:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka and Kb
Replies: 5
Views: 16

Ka and Kb

Are Ka and Kb calculated differently?
by Angela Patel 2J
Wed Jan 15, 2020 10:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6C#9
Replies: 2
Views: 9

Re: 6C#9

Can you write out the problem?
by Angela Patel 2J
Thu Jan 09, 2020 6:10 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Chemical Activity of a Compound
Replies: 5
Views: 26

Re: Chemical Activity of a Compound

What is chemical activity?
by Angela Patel 2J
Thu Jan 09, 2020 6:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.57
Replies: 1
Views: 16

Re: 5.57

You know that the inital mass is equal to the final mass, and you can use this to solve for the initial concentration of NO
by Angela Patel 2J
Thu Jan 09, 2020 6:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.39
Replies: 1
Views: 16

Re: 5.39

Yeah I can't seem to find it either. Maybe it's talking about table 5E.1. I might be wrong, but it seems like you should be able to do the problem without any extra information though?
by Angela Patel 2J
Thu Jan 09, 2020 5:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solid/liquid
Replies: 7
Views: 25

Re: solid/liquid

I still don't really understand why solids aren't included, is it just because they don't have a concentration?
by Angela Patel 2J
Thu Jan 09, 2020 5:55 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: kc and kp
Replies: 3
Views: 15

Re: kc and kp

So we should convert all individual concentrations into pressures for gases using the ideal gas law, and not worry about converting Kc to Kp directly.
by Angela Patel 2J
Sat Dec 07, 2019 9:31 pm
Forum: Photoelectric Effect
Topic: Dino Nuggets question 8b
Replies: 3
Views: 75

Re: Dino Nuggets question 8b

For reference: 8b) A newly designed laser pointer with a certain frequency is pointed at a sodium metal surface. An electron is ejected from the metal surface with wavelength 1.10 nm. What is the frequency of the light from the laser pointer? The work function of sodium is 150.6 kJ∙mol-1. I'll just...
by Angela Patel 2J
Thu Dec 05, 2019 11:59 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ionization Constants on test
Replies: 1
Views: 22

Re: Ionization Constants on test

Since we don't have to do calculations with Ka I would guess that we don't need to use ionization constants. They would only be given to us when we need to rank weak acids/bases in terms of strength.
by Angela Patel 2J
Thu Dec 05, 2019 11:57 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxolate Chelate
Replies: 6
Views: 52

Re: Oxolate Chelate

are chelates only bidentate?
by Angela Patel 2J
Thu Dec 05, 2019 11:56 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: London disperson
Replies: 6
Views: 23

Re: London disperson

Is London dispersion the same thing as dipole-dipole or van der waals forces? Do we have to mention all of these
by Angela Patel 2J
Thu Dec 05, 2019 11:55 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Hemoglobin
Replies: 1
Views: 23

Re: Hemoglobin

The same ligand binds to the transition metal more than once. Four nitrogen atoms in the ligand bind to iron, so it is tetradentate
by Angela Patel 2J
Thu Dec 05, 2019 11:53 am
Forum: Air Pollution & Acid Rain
Topic: final?
Replies: 5
Views: 87

Re: final?

The chemical equation is not that difficult to understand, just think about water and co2 in the atmosphere combining to form carbonic acid. I would know the formula and the concept behind it.
by Angela Patel 2J
Wed Nov 27, 2019 9:19 am
Forum: Dipole Moments
Topic: Hydrogen Bonds vs Double Bonds
Replies: 2
Views: 20

Re: Hydrogen Bonds vs Double Bonds

Two hydrogen bonds would not form between two atoms. A double bond consists of a sigma bond and a pi bond between two atoms that are sharing electrons. Hydrogen bonds are much weaker and can only form between hydrogen and oxygen/nitrogen/fluorine.
by Angela Patel 2J
Wed Nov 27, 2019 9:17 am
Forum: Lewis Acids & Bases
Topic: Identifying Acids and Bases
Replies: 8
Views: 36

Re: Identifying Acids and Bases

Why do strong acids have elements in group 1/2?
by Angela Patel 2J
Wed Nov 27, 2019 9:15 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation Number vs. Coordination Number
Replies: 8
Views: 42

Re: Oxidation Number vs. Coordination Number

why is it called oxidation number if it is just the charge on the ion/transition metal?
by Angela Patel 2J
Wed Nov 27, 2019 9:14 am
Forum: Naming
Topic: Ambiguous Cases
Replies: 1
Views: 29

Re: Ambiguous Cases

You could probably figure it out if you drew out the lewis structure. But I doubt that we would be given any of these ambiguous cases since it was not mentioned in lecture or discussion (at least mine).
by Angela Patel 2J
Wed Nov 27, 2019 9:11 am
Forum: Naming
Topic: Bis,tris, etc
Replies: 6
Views: 46

Re: Bis,tris, etc

Do you use them just when the name starts with bi or di or is it just when it has bi, di, etc anywhere in the name?
by Angela Patel 2J
Wed Nov 27, 2019 9:10 am
Forum: Naming
Topic: OH2 vs H2O Coordination Complex Chemical Formula
Replies: 3
Views: 21

Re: OH2 vs H2O Coordination Complex Chemical Formula

I think it depends on the structure of the molecule. If the oxygen atom is the one binding to the metal on the left, then you would out OH2 in order to show the actual arrangement of the atoms in the coordination complex. Both are technically 'correct' but one can help you better visualize the struc...
by Angela Patel 2J
Mon Nov 25, 2019 3:36 pm
Forum: Naming
Topic: Focus 9C.3
Replies: 4
Views: 24

Focus 9C.3

In part a), how do we know that there are three potassium atoms?
by Angela Patel 2J
Mon Nov 25, 2019 10:25 am
Forum: Lewis Acids & Bases
Topic: Why do transition metal cations form complexes?
Replies: 2
Views: 29

Re: Why do transition metal cations form complexes?

They form complexes because they can accept multiple electron pairs from ligands. This is because of their partially-filled d subshells.
by Angela Patel 2J
Mon Nov 25, 2019 10:23 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Counting Total Charges Of A Coordination Compound
Replies: 1
Views: 33

Re: Counting Total Charges Of A Coordination Compound

You can calculate formal charge but it's just easier to do it when you know the charges of the individual ligands. Plus, it's important to remember that transition metals don't often follow the octet rule, so it can be easier to find the charge of the transition metal using the "counting" ...
by Angela Patel 2J
Mon Nov 25, 2019 10:17 am
Forum: Naming
Topic: Coordination shape
Replies: 3
Views: 31

Re: Coordination shape

GFolk_1G wrote:I believe you would need more information to identify exactly which shape it is such as hybridization or specific numbers of lone pairs/bonding pairs

Yeah. You can't know which one it is based on the coordination number alone. You would have to be given other information.
by Angela Patel 2J
Mon Nov 25, 2019 10:15 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: ligand bonding sites
Replies: 2
Views: 29

Re: ligand bonding sites

Think about the examples that we looked at in lecture of monodentate vs bidentate vs tetradentate ligands. The number of bonds that a single ligand makes with the transition metal determines what we call it.
by Angela Patel 2J
Mon Nov 25, 2019 10:13 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: Molecule BH2 polar or nonpolar
Replies: 2
Views: 33

Re: Molecule BH2 polar or nonpolar

The polar bonds cancel each other out because the molecule has a linear shape. Always take shape into consideration when thinking about whether a molecule is polar or nonpolar!
by Angela Patel 2J
Wed Nov 13, 2019 12:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Single/Double Bonds in Resonance
Replies: 6
Views: 42

Re: Single/Double Bonds in Resonance

So all resonance structures for a molecule have the same shape? Is this always true?
by Angela Patel 2J
Wed Nov 13, 2019 12:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape Name
Replies: 17
Views: 122

Re: Molecular Shape Name

I think you should try to remember all of them since it will help you remember how the structure looks. It's probably not 100% necessary, but it would be helpful.
by Angela Patel 2J
Wed Nov 13, 2019 12:13 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: intermolecular forces
Replies: 8
Views: 53

Re: intermolecular forces

Are we expected to memorize electronegativities in order to tell whether a molecule has a dipole? And what is the difference between dipole and london forces?
by Angela Patel 2J
Wed Nov 13, 2019 12:12 pm
Forum: Octet Exceptions
Topic: Incomplete Octets
Replies: 4
Views: 62

Re: Incomplete Octets

It's important to note that elements like carbon, nitrogen, and oxygen should not have expanded octets
by Angela Patel 2J
Fri Nov 08, 2019 10:04 am
Forum: Hybridization
Topic: Pi bonds
Replies: 8
Views: 284

Re: Pi bonds

505312292 wrote:
605110118 wrote:What is the difference between pi and sigma?

sigma is all single bonds and pi is the second bond in a double bond


I still don't really understand this concept, can someone explain it further?
by Angela Patel 2J
Fri Nov 08, 2019 10:02 am
Forum: Formal Charge and Oxidation Numbers
Topic: central atom
Replies: 21
Views: 104

Re: central atom

How do we know what the central atom should be?
by Angela Patel 2J
Fri Nov 08, 2019 10:00 am
Forum: Formal Charge and Oxidation Numbers
Topic: Chlorine in center: electronegativity vs. formal charge
Replies: 4
Views: 50

Re: Chlorine in center: electronegativity vs. formal charge

VPatankar_3L wrote:Also since Oxygen is more electronegative that Chlorine, it can carry the -1 charge.

Is oxygen more electronegative than chlorine? I thought it was the other way around?
by Angela Patel 2J
Fri Nov 08, 2019 9:57 am
Forum: Formal Charge and Oxidation Numbers
Topic: Which lewis structure will make the dominant contribution to a resonance hybrid?
Replies: 5
Views: 36

Re: Which lewis structure will make the dominant contribution to a resonance hybrid?

The most important thing is to make sure that you are using the correct number of electrons. If there is multiple ways to do so, then you must look at formal charges and choose the structure that makes the most sense given what we know about electronegativity and bonding.
by Angela Patel 2J
Fri Nov 08, 2019 9:53 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarisability vs Polarizing Power
Replies: 15
Views: 111

Re: Polarisability vs Polarizing Power

Small and highly charged cations are said to have very high polarizing power, because they will attract negative charge. For example, the Al3+ ion has very high polarizing power.
by Angela Patel 2J
Wed Oct 30, 2019 6:22 pm
Forum: Trends in The Periodic Table
Topic: Noble Gas
Replies: 4
Views: 44

Re: Noble Gas

Are noble gases ever included in compounds? Do they ever share or donate electrons?
by Angela Patel 2J
Wed Oct 30, 2019 6:19 pm
Forum: Resonance Structures
Topic: 2C.3
Replies: 2
Views: 50

Re: 2C.3

I think the diagram is just pointing out that you can make the Cl formal charge 0 when there are two double bonds with oxygen.
by Angela Patel 2J
Wed Oct 30, 2019 6:17 pm
Forum: Electronegativity
Topic: Electronegativity trends
Replies: 5
Views: 30

Re: Electronegativity trends

What about electronegativity? Does that count as a trend in the periodic table or is it just ionization energy / electron affinity?
by Angela Patel 2J
Wed Oct 30, 2019 6:15 pm
Forum: Ionic & Covalent Bonds
Topic: Partial charge
Replies: 4
Views: 28

Re: Partial charge

Why would they be found in ionic compounds? I thought partial charge was when atoms share electrons unequally.
by Angela Patel 2J
Wed Oct 30, 2019 6:13 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 9
Views: 79

Re: Radicals

Why do radicals exist?
by Angela Patel 2J
Fri Oct 25, 2019 5:38 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 5
Views: 45

Re: Formal Charge

How do we know what the formal charge for the molecule should add up to? Is it always most stable if it adds up to 0?
by Angela Patel 2J
Fri Oct 25, 2019 5:36 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 23

Re: Electron Affinity

I think electron affinities can be positive or negative depending on whether energy is released or used in order to form an anion.
by Angela Patel 2J
Fri Oct 25, 2019 5:34 pm
Forum: Octet Exceptions
Topic: Reasoning behind the exceptions
Replies: 3
Views: 46

Re: Reasoning behind the exceptions

Aluminum can also have 6 valence electrons. As well, the electrons for P, S, and Cl would be in the 3d state because this is a lower energy level than the 4s state.
by Angela Patel 2J
Fri Oct 25, 2019 5:32 pm
Forum: Resonance Structures
Topic: Lewis Structures
Replies: 3
Views: 26

Re: Lewis Structures

Just remember that none of the lewis structures that we can draw for a molecule with resonance are actually correct, it is a blend of all of the possibilities as we discussed in class.
by Angela Patel 2J
Fri Oct 25, 2019 5:31 pm
Forum: Resonance Structures
Topic: Lewis Structures
Replies: 3
Views: 26

Re: Lewis Structures

You can know by drawing it out. If the molecule has resonance, then it will have the same arrangement of atoms but different ways to share the electrons, i.e. different ways to place a double bond and still satisfy the octet rule/create the most stable molecule. However many ways you can draw it and...
by Angela Patel 2J
Wed Oct 16, 2019 5:55 pm
Forum: *Shrodinger Equation
Topic: psi vs psi^2
Replies: 7
Views: 80

Re: psi vs psi^2

Why can orbitals be referred to in terms of psi OR psi^2? Are they interchangeable?
by Angela Patel 2J
Wed Oct 16, 2019 5:52 pm
Forum: Quantum Numbers and The H-Atom
Topic: X Y and Z
Replies: 7
Views: 76

Re: X Y and Z

There is no convention for which magnetic quantum number is associated with which plane for orbitals. Because of this, either the values will be randomly assigned to a specific orbital (given by the problem/textbook/etc) or we will just have to write all of the possible options and accept that it is...
by Angela Patel 2J
Wed Oct 16, 2019 5:48 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: how to express answer
Replies: 6
Views: 24

Re: how to express answer

I think in lecture Professor Lavelle mentioned that in the best case scenario Δp*Δx = h/4pi, but in most situations it's actually larger than h/4pi. In the example that he did with the baseball he wrote the final velocity as v = 3.2X10^10 m/s, so I would guess that we are looking at the best case sc...
by Angela Patel 2J
Wed Oct 16, 2019 5:43 pm
Forum: DeBroglie Equation
Topic: De Broglie Wavelength
Replies: 7
Views: 57

Re: De Broglie Wavelength

Does calculating the De Broglie wavelength just mean calculating the wavelength of an electron?
by Angela Patel 2J
Wed Oct 16, 2019 5:42 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1D.25
Replies: 3
Views: 46

Re: 1D.25

Yes, you can look at the quantum numbers in order to identify whether or not a certain orbital can exist. We know that 2d cannot exist because the angular momentum quantum number can never equal 2 when n =2 (It must be 0 or 1, which correspond to the s or p orbitals). On the other hand, 6f can exist...
by Angela Patel 2J
Sun Oct 13, 2019 6:32 pm
Forum: Properties of Light
Topic: Atomic Spectra Pre-Assessment #13
Replies: 1
Views: 13

Re: Atomic Spectra Pre-Assessment #13

They technically provide the same data. Absorption line spectra display the wavelengths of light absorbed, and emission line spectra display the wavelengths of light emitted. You can measure either to get the same information, it just depends on what experimental tools were available.
by Angela Patel 2J
Sun Oct 13, 2019 6:25 pm
Forum: Photoelectric Effect
Topic: confirmation.
Replies: 5
Views: 38

Re: confirmation.

Yes. We learned that it was unexpected, but changing to higher intensity light did not eject electrons, but changing the frequency of light emitted did. This demonstrates the particle-like qualities of light.
by Angela Patel 2J
Sun Oct 13, 2019 6:23 pm
Forum: DeBroglie Equation
Topic: De Broglie Equation Clarification
Replies: 4
Views: 46

Re: De Broglie Equation Clarification

I think by wavelike properties it also means that there is a quantifiable wavelength and frequency. Like how we discussed in class that all objects theoretically have wavelike properties, but only we can only measure it for small objects.
by Angela Patel 2J
Sun Oct 13, 2019 6:17 pm
Forum: Properties of Light
Topic: Visualizing wave-particle duality
Replies: 3
Views: 45

Re: Visualizing wave-particle duality

Light has both wave-like and particle-like qualities. It is hard to define light as just one thing because it has different properties depending on what experiments you are doing. We can think of light as being made up of photons or we can think of it as behaving like a wave would (with a specific w...
by Angela Patel 2J
Mon Oct 07, 2019 7:05 pm
Forum: SI Units, Unit Conversions
Topic: Writing formulas
Replies: 4
Views: 71

Re: Writing formulas

So we would need to know how to write the chemical formula given the names of compounds? Where would we find that kind of information?
by Angela Patel 2J
Sun Oct 06, 2019 8:14 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Wavelength Plausibility
Replies: 30
Views: 872

Re: Wavelength Plausibility

He said that it is 720 to 400 but that we can just remember 700 to 400 since it's easier!
by Angela Patel 2J
Wed Oct 02, 2019 11:01 am
Forum: Empirical & Molecular Formulas
Topic: Homework Problem E9 Part B [ENDORSED]
Replies: 3
Views: 89

Re: Homework Problem E9 Part B [ENDORSED]

You are basically trying to find the number of salt molecules in 5.15 g. To do this, you have to convert grams to moles by dividing by the molar mass of the whole molecule. Then you must convert that number of moles to number of molecules by multiplying by 6.022 x 10^23 (the number of molecules in o...
by Angela Patel 2J
Mon Sep 30, 2019 9:08 pm
Forum: Empirical & Molecular Formulas
Topic: Homework Problem E.9c
Replies: 5
Views: 72

Re: Homework Problem E.9c

How do you find the formula for magnesium sulfate heptahydrate?
by Angela Patel 2J
Mon Sep 30, 2019 9:02 pm
Forum: Empirical & Molecular Formulas
Topic: Percent Mass Composition
Replies: 7
Views: 147

Re: Percent Mass Composition

Why do we need to find the percent mass composition? What does it help us to find?
by Angela Patel 2J
Mon Sep 30, 2019 8:59 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Reactions
Replies: 25
Views: 292

Re: Balancing Reactions

Have you guys been showing all of the work when you do these problems for homework and practice? Is it better to show each step when you add a stoichiometric coefficient or do you just use the same equation and balance it all at once?
by Angela Patel 2J
Mon Sep 30, 2019 8:56 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 132
Views: 77701

Re: Reading the textbook [ENDORSED]

I find it more helpful to look at the answers after I've done each problem. That way I know if I'm making a mistake and I don't have to redo all of the problems just because I misunderstood something. :)

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