Search found 90 matches

by Lilyana Villa 3L
Sun Feb 28, 2021 7:17 pm
Forum: Balancing Redox Reactions
Topic: Textbook Problem 6K.5 a
Replies: 2
Views: 11

Textbook Problem 6K.5 a

Hello! I had a question about part a of textbook problem 6K. 5: "Balance each of the following skeletal equations by using oxidation and reduction half-reactions. All the reactions take place in basic solution. Identify the oxidizing agent and reducing agent in each reaction. (a) Reaction of oz...
by Lilyana Villa 3L
Sun Feb 28, 2021 3:12 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Sapling #18 (Week 7/8)
Replies: 1
Views: 16

Sapling #18 (Week 7/8)

"One of the most recognizable corrosion reactions is the rusting of iron. Rust is caused by iron reacting with oxygen gas in the presence of water to create an oxide layer. Iron can form several different oxides, each having its own unique color. Red rust is caused by the formation of iron(III)...
by Lilyana Villa 3L
Sun Feb 28, 2021 3:06 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Solids in a Cell Diagram
Replies: 1
Views: 5

Solids in a Cell Diagram

Just to clarify, we always put the solids on the outermost part of the cell diagrams right? Or does the placement of the different phases not matter?
by Lilyana Villa 3L
Sun Feb 28, 2021 2:51 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Ranking Oxidizing Agents
Replies: 5
Views: 13

Ranking Oxidizing Agents

How do you determine which elements are the best oxidizing agents?
by Lilyana Villa 3L
Sun Feb 28, 2021 2:42 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Sapling #9 (Week 7/8)
Replies: 3
Views: 22

Sapling #9 (Week 7/8)

Hello! I am stuck on question 9 on this week's sapling: "A galvanic (voltaic) cell consists of an electrode composed of aluminum in a 1.0 M aluminum ion solution and another electrode composed of copper in a 1.0 M copper(I) ion solution, connected by a salt bridge. Calculate the standard potent...
by Lilyana Villa 3L
Sun Feb 21, 2021 6:49 pm
Forum: Calculating Work of Expansion
Topic: Calculating W
Replies: 4
Views: 23

Re: Calculating W

For this question, you would use the equation S=kB*lnW. Since we are solving for W and we know S and kB, we would divide kB on both sides to isolate lnW, then use e on both sides of the equation to eliminate the natural log, so then you would be left with W=e^(S/kB). Plug in Boltzmann's constant and...
by Lilyana Villa 3L
Fri Feb 19, 2021 12:14 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: STP (standard temperature and pressure)
Replies: 8
Views: 34

STP (standard temperature and pressure)

If a problem tells us that the system is under STP conditions (standard temperature and pressure), would the temperature be 0 degrees Celsius or 25 degrees Celsius for this system? I've heard conflicting answers so I'm not sure which one is correct. Thank you in advance!
by Lilyana Villa 3L
Thu Feb 18, 2021 11:25 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: Residual Entropy
Replies: 8
Views: 25

Re: Residual Entropy

Yes, you are correct! If it says positional entropy, know that's just another way of saying residual entropy and you would still use that equation.
by Lilyana Villa 3L
Thu Feb 18, 2021 11:19 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: q and w for an Isolated System
Replies: 14
Views: 43

q and w for an Isolated System

Just to check, for an isolated system, q would be zero because the system would be insulated and not allow for heat transfer to occur between the system and surroundings right? Would work also be zero?
by Lilyana Villa 3L
Thu Feb 18, 2021 11:15 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Comparing Molar Entropies of Different Compounds
Replies: 9
Views: 36

Comparing Molar Entropies of Different Compounds

If we're given two different compounds and asked to determine which one has a higher molar entropy, would the larger molecule have a higher molar entropy since it would be more complex? Also, do we take into consideration the state of the compound (ex. gas, liquid, solid) when trying to figure out w...
by Lilyana Villa 3L
Sun Feb 14, 2021 6:20 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Textbook Problem 4F.1a
Replies: 2
Views: 20

Textbook Problem 4F.1a

Hello! I had a question regarding the solution given in the manual for 4F.1a: "A human body generates heat at the rate of about 100 W (1W=1J⋅s^−1). (a) At what rate does your body heat generate entropy in your surroundings, taken to be at 20°C? I understand that to get the answer you are suppos...
by Lilyana Villa 3L
Sun Feb 14, 2021 6:00 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeter
Replies: 12
Views: 35

Bomb Calorimeter

Just to check, is a bomb calorimeter considered a closed or isolated system?
by Lilyana Villa 3L
Sun Feb 14, 2021 4:57 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal Irreversible Expansion?
Replies: 2
Views: 31

Isothermal Irreversible Expansion?

Is it possible for irreversible expansion to be isothermal? If this is the case could someone explain why this could be? I thought temperature always changes during irreversible expansion. Thank you in advance!
by Lilyana Villa 3L
Sun Feb 14, 2021 4:05 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity at Equilibrium?
Replies: 10
Views: 29

Spontaneity at Equilibrium?

If a reaction is at equilibrium, would it be considered nonspontaneous?
by Lilyana Villa 3L
Fri Feb 12, 2021 1:25 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: Textbook Problem 4H.5a
Replies: 2
Views: 7

Textbook Problem 4H.5a

Hello! I had a question regarding textbook problem 4H.5a. "Which substance in each of the following pairs would you expect to have the higher standard molar entropy at 298 K and 1 bar? Explain your reasoning. (a) Iodine vapor or bromine vapor." The solutions manual says that Iodine vapor h...
by Lilyana Villa 3L
Sun Feb 07, 2021 10:04 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Textbook Problem 4D. 3
Replies: 1
Views: 24

Textbook Problem 4D. 3

Hi! I have a question regarding question 4D.3 from the textbook: "The reaction of 1.40 g of carbon monoxide with excess water vapor to produce carbon dioxide and hydrogen gases in a bomb calorimeter causes the temperature of the calorimeter assembly to rise from 22.113°C to 22.799°C. The calori...
by Lilyana Villa 3L
Sun Feb 07, 2021 9:56 pm
Forum: Calculating Work of Expansion
Topic: Week 3/4 Sapling Homework: #15
Replies: 9
Views: 52

Week 3/4 Sapling Homework: #15

Hello! I have a question regarding #15 from the Week 3/4 Sapling Homework. Q15) "Automobile airbags contain solid sodium azide, NaN3, that reacts to produce nitrogen gas when heated, thus inflating the bag. 2NaN3(s)-->2Na(s)+3N2(g). Calculate the value of work, w, for the system if 19.8 g NaN3 ...
by Lilyana Villa 3L
Sun Feb 07, 2021 2:32 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 4D.7: Assuming Temperature
Replies: 1
Views: 19

4D.7: Assuming Temperature

Hello! I have a question regarding 4D.7 from the textbook: "Oxygen difluoride is a colorless, very poisonous gas that reacts rapidly and exothermically with water vapor to produce O2 and HF: OF2(g) + H2O(g) --> O2(g) + HF(g), delta H = -318 kJ. What is the internal energy for the reaction of 1....
by Lilyana Villa 3L
Sat Feb 06, 2021 10:57 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Sign of Specific Heat Capacities
Replies: 3
Views: 20

Sign of Specific Heat Capacities

If we're solving for specific heat capacity and we get a negative number as our solution, is it correct to just take the absolute value of it since specific heat capacities are always positive? Or should we never get a negative number when solving for specific heat capacity?
by Lilyana Villa 3L
Sat Feb 06, 2021 8:48 pm
Forum: Calculating Work of Expansion
Topic: Reversible and Irreversible Expansion
Replies: 3
Views: 20

Reversible and Irreversible Expansion

Hello! For questions regarding reversible or irreversible expansion, will the problem always explicitly tell us whether we're dealing with reversible/irreversible expansion or do we need to be able to figure that out ourselves using the information given in the problem?
by Lilyana Villa 3L
Sun Jan 31, 2021 8:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific Heat Capacity
Replies: 3
Views: 20

Specific Heat Capacity

Hello! Could someone explain to me why specific heat capacity is an intensive property?
by Lilyana Villa 3L
Thu Jan 28, 2021 10:15 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: How Does Temperature Affect the Equilibrium Constant?
Replies: 25
Views: 76

How Does Temperature Affect the Equilibrium Constant?

Hello! Could someone tell me how raising the temperature affects K? For example, for endothermic reactions (or exothermic reactions), does increasing temperature increase or decrease K? Thank you!
by Lilyana Villa 3L
Wed Jan 27, 2021 10:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 51.3
Replies: 1
Views: 13

Re: Textbook Problem 51.3

To decide which one would be more thermodynamically stable, we would look at the equilibrium constants of both the Cl2 and F2 reactions. A smaller equilibrium constant means that reactant formation would be more favored in the reaction, which means the reactants are more stable, while a larger K mea...
by Lilyana Villa 3L
Wed Jan 27, 2021 10:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Biological Examples
Replies: 2
Views: 34

Re: Biological Examples

From what I understood in his office hours, Dr. Lavelle said that we don't necessarily have to know how to solve for/describe ATP hydrolysis or other biological examples he gave in the learning objectives at the top of our heads without any given information. Rather, he meant that with the skills we...
by Lilyana Villa 3L
Wed Jan 27, 2021 10:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 6D.9 Denominator
Replies: 1
Views: 10

Re: 6D.9 Denominator

The answer key shows it this way because we know that 2.4% of the benzoic acid deprotonated, which means 97.6% of benzoic acid remained unprotonated at equilibrium. To determine how much of the acid is left unprotonated at equilibrium, you would just find 97.6% of 0.110M, which can be found by (1-0....
by Lilyana Villa 3L
Sun Jan 24, 2021 2:37 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Textbook Problem 4D. 15
Replies: 2
Views: 19

Textbook Problem 4D. 15

Hi! I had a question regarding 4D.15 in the textbook: Determine the reaction enthalpy for the hydrogenation of ethyne to ethane, C2H2(g) + 2H2(g) --> C2H6(g), from the following data: delta Hc (C2H2,g)=-1300 kJ/mol, delta Hc (C2H6,g)=-1560 kJ/mol, and delta Hc (H2,g)=-286 kJ/mol. Why couldn't we jus...
by Lilyana Villa 3L
Sun Jan 24, 2021 2:19 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Textbook Question 6E.3
Replies: 1
Views: 16

Re: Textbook Question 6E.3

I'm not quite sure about the exact threshold of values, but I remember Dr. Lavelle in his office hours said that the only polyprotic acid that we should calculate the 2nd ionization for is sulfuric acid (since it's a strong acid), and for other polyprotic acids, we can ignore the 2nd ionization sinc...
by Lilyana Villa 3L
Sun Jan 24, 2021 1:29 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Most stable form
Replies: 2
Views: 21

Re: Most stable form

I believe what Dr. Lavelle means by "most stable form" is the form we typically find this compound at normal temperatures (like 25 degrees Celsius). For example, carbon is in its most stable form as graphite (a solid) at normal temperatures. You usually wouldn't see carbon itself as a gas,...
by Lilyana Villa 3L
Sun Jan 24, 2021 1:14 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5G.11
Replies: 2
Views: 14

Re: 5G.11

Hi! I don't know what exact question you have about this problem, but to solve for the reaction quotient you would use the same method/formula for the K value, which is: K=([products]/[reactants]), making sure to account for the stoichiometric coefficient by raising each compound to the power of its...
by Lilyana Villa 3L
Sun Jan 24, 2021 1:00 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5I.13 Question
Replies: 1
Views: 13

Re: 5I.13 Question

Hi! For this problem, Cl2 would be more stable than F2 relative to its atoms since the Cl2 reaction has a smaller equilibrium constant than the F2 reaction. A smaller equilibrium constant means that the formation of reactants would be more favored in that reaction (and the reactants are less likely ...
by Lilyana Villa 3L
Sun Jan 17, 2021 3:08 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: increasing/decreasing a solid/liquid
Replies: 6
Views: 25

Re: increasing/decreasing a solid/liquid

The reaction does not change if a solid or liquid is increased/decreased. Since we don't include solids/liquids when determining the equilibrium constant, adjusting the amount of solids and liquids cannot affect the reaction's equilibrium state.
by Lilyana Villa 3L
Sun Jan 17, 2021 2:16 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Number 2
Replies: 2
Views: 11

Re: Sapling Number 2

After you determine the concentrations, I would create an ICE table so you can visualize what changes are going on in the reaction for it to reach equilibrium. For the E part of the ICE table, you should have [SO3]=0.192-2x, [SO2]=2x, and [O2]=x. Since you already know the equilibrium concentration ...
by Lilyana Villa 3L
Sun Jan 17, 2021 2:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: assuming endothermic
Replies: 2
Views: 31

Re: assuming endothermic

I think you might be referring to problems that have a reaction that shows a diatomic molecule being broken into single molecules (Ex. X2<-->X). We know this is an endothermic reaction without being told delta H because breaking bonds is an endothermic process, therefore we can assume from these spe...
by Lilyana Villa 3L
Sun Jan 17, 2021 1:43 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Calculating pH/pOH for Weak Acids/Bases
Replies: 7
Views: 54

Calculating pH/pOH for Weak Acids/Bases

Hello! Could someone explain to me why we can't calculate the pH/pOH of a weak acid/base using -log[] when given the concentration?
by Lilyana Villa 3L
Sat Jan 16, 2021 7:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding Equilibrium Concentrations
Replies: 5
Views: 45

Finding Equilibrium Concentrations

If we are asked in a problem to find the equilibrium concentrations of the reactants and products when given nonzero initial concentrations for all of the reactants and products, how are we supposed to determine which side of the reaction experiences the positive/negative change? Meaning that on the...
by Lilyana Villa 3L
Sun Jan 10, 2021 3:04 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.i #15
Replies: 2
Views: 17

Re: 5.i #15

Actually, since NH3 and H2S are on the product side of the reaction, you would add 0.200 to x (0.200+x) for NH3 and H2S would correspond to +x. If NH3 and H2S were on the reactant side, then you would subtract x from 0.200 for NH3. Using the quadratic formula, you should get 0.0008 for x. Once you g...
by Lilyana Villa 3L
Sun Jan 10, 2021 2:38 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5.i #13 (b)
Replies: 1
Views: 19

Re: 5.i #13 (b)

I see your mistake! In the part that corresponds to 4AC in the quadratic formula, you put A=2 instead of A=4. A=4 in this case because when you create your ICE table, you find that the change in the molar concentration of F corresponds to 2x. When you plug it into your equilibrium constant expressio...
by Lilyana Villa 3L
Sun Jan 10, 2021 1:54 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook problem 5G.5
Replies: 5
Views: 29

Re: Textbook problem 5G.5

Yes I believe so! It would make sense that both of those flasks would have the same amount of X and X2 since flask 3 represents the point equilibrium was reached. Once equilibrium is reached, the concentrations of the product and reactant don't change over time, so flask 4 should be the same as flas...
by Lilyana Villa 3L
Sat Jan 09, 2021 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reactants and equilibrium
Replies: 3
Views: 33

Re: Reactants and equilibrium

A higher concentration of reactants than products at equilibrium means that the reactants are favored in this reaction, or that "equilibrium sits to the left." In this case, the equilibrium constant, K, would be less than 1.
by Lilyana Villa 3L
Thu Jan 07, 2021 10:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 5G.1
Replies: 2
Views: 17

Textbook Problem 5G.1

Hi! For question 5G.1d from the textbook, why is the statement, "If one starts with higher concentrations of reactants, the equilibrium concentrations of the products will be larger." considered true? The answer to this question is probably straightforward but I can't seem to figure it out...
by Lilyana Villa 3L
Sat Dec 07, 2019 11:34 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE formula
Replies: 7
Views: 266

Re: AXE formula

The E of the VSEPER formula represents the number of lone pairs the central atom has.
by Lilyana Villa 3L
Sat Dec 07, 2019 11:32 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: different forces
Replies: 1
Views: 101

Re: different forces

The forces of intermolecular forces we should know are London forces, which are present among any molecule (and the weakest), dipole-dipole (stronger than London), which is present in polar molecules, and hydrogen bonding, which is the strongest type of dipole dipole force.
by Lilyana Villa 3L
Sat Dec 07, 2019 11:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent molecules
Replies: 1
Views: 116

Re: Bent molecules

All molecules with a bent shape are polar because even though the dipole moments of the two bonded atoms go towards the bonded atoms and not the central, it doesn't cancel because the bonded atoms are not opposite one another.
by Lilyana Villa 3L
Sat Dec 07, 2019 11:10 pm
Forum: Coordinate Covalent Bonds
Topic: Cisplatin
Replies: 3
Views: 158

Re: Cisplatin

All you really need to know is just that cisplatin is a chemotherapy drug whose two Cl ligands bind to guanine in order to prevent the DNA polymerase from attaching to guanine. So pretty much exactly what you said.
by Lilyana Villa 3L
Sat Dec 07, 2019 10:43 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: base constants
Replies: 1
Views: 45

Re: base constants

No, you do not need to memorize the base constants, but you need to know how to calculate them when given other values like pKa, pKb, etc.
by Lilyana Villa 3L
Sun Dec 01, 2019 11:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: charge and coordination number
Replies: 2
Views: 25

Re: charge and coordination number

I don't believe there is a relationship between charge and coordination number.
by Lilyana Villa 3L
Sun Dec 01, 2019 11:12 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Determing Coordination Number
Replies: 5
Views: 69

Re: Determing Coordination Number

The coordination number corresponds to the number of bonds around the central atom. I think this is the only way but its very easy so you don't need to use another method.
by Lilyana Villa 3L
Sun Dec 01, 2019 11:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Shapes and Corners
Replies: 2
Views: 35

Re: Shapes and Corners

I'm pretty sure there can be both odd and even numbers of ligands around a central atom. It's not common but its possible.
by Lilyana Villa 3L
Sun Dec 01, 2019 10:58 pm
Forum: Resonance Structures
Topic: Carbon
Replies: 4
Views: 162

Re: Carbon

A regular carbon atom can never hold more than 8 electrons in its valence shell. It isn't included in the elements that are able to have an expanded octet.
by Lilyana Villa 3L
Sun Dec 01, 2019 10:54 pm
Forum: Lewis Acids & Bases
Topic: Conjugates
Replies: 3
Views: 49

Re: Conjugates

A conjugate acid is a base that was donated a hydrogen ion and a conjugate base is an acid with one less hydrogen ion.
by Lilyana Villa 3L
Sun Nov 24, 2019 11:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape of carbon Dioxide
Replies: 10
Views: 163

Re: Molecular shape of carbon Dioxide

The molecular shape of carbon dioxide would be linear with a bond angle of 180 degrees since there are 2 regions of electron density with no lone pairs.
by Lilyana Villa 3L
Sun Nov 24, 2019 11:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: t shape and see saw
Replies: 6
Views: 129

Re: t shape and see saw

The difference between trigonal bipyramidal and seesaw is that seesaw has one lone pair and 4 bonded atoms while trigonal bipyramidal has 5 bonded atoms w/ no lone pairs. For tetrahedral and t-shaped, tetrahedral is a shape with 4 regions of electron density (4 bonded atoms w/ no lone pairs) and t s...
by Lilyana Villa 3L
Sun Nov 24, 2019 11:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 7
Views: 169

Re: Bond Angles

The reason why some molecules have bond angles that are "smaller" than the value of the general shape is because they have lone pairs. Molecules with lone pairs will have angles that are smaller than a given value because lone pairs have a stronger repelling effect than bonded electrons, w...
by Lilyana Villa 3L
Sun Nov 24, 2019 11:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Hydrogen Bonding
Replies: 2
Views: 50

Hydrogen Bonding

Okay so I'm confused about hydrogen bonding sites. For example, if a nitrogen was already bonded to a hydrogen but still had a lone pair of electrons, would that nitrogen still be considered a hydrogen bonding site for a new hydrogen bond or would it not since it is already bonded to a hydrogen?
by Lilyana Villa 3L
Sun Nov 24, 2019 11:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shape
Replies: 21
Views: 472

Re: T-shape

A tshaped molecule is a molecule that has 2 lone pairs and 3 bonded atoms. The bond angles would be less than 90 degrees.
by Lilyana Villa 3L
Sun Nov 17, 2019 9:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial lone pairs
Replies: 2
Views: 48

Re: Equatorial lone pairs

The lone pair comes from the equatorial plane because the lowest energy is achieved when a lone pair is equatorial rather than an axial lone pair. An equatorial lone pair would only repel the 2 axial bonds while an axial lone pair would repel the 3 equatorial bonds.
by Lilyana Villa 3L
Sun Nov 17, 2019 8:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape
Replies: 3
Views: 58

Re: Molecular shape

I believe sawhorse is just another name for seesaw, so yes they both refer to the same shape. However, seesaw will be the name that we'd use on homework and exams.
by Lilyana Villa 3L
Sun Nov 17, 2019 8:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shapes
Replies: 6
Views: 115

Re: Molecular Shapes

For the test and final, yes we need to memorize all of them because it'll be likely that we'll be given the more complex ones on the exams like seesaw and t-shaped.
by Lilyana Villa 3L
Sun Nov 17, 2019 8:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 71

Bond Angles

Is there any circumstance where the bond angles of molecules w/ lone pairs will be greater than the angle of the general shape? Or will the bond angle always be smaller?
by Lilyana Villa 3L
Sun Nov 17, 2019 8:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles for molecules w/ multiple central atoms
Replies: 1
Views: 51

Bond Angles for molecules w/ multiple central atoms

How do we determine the bond angles for molecules with more than 1 central atom? I know we are supposed to treat each central atom as its own but would the bond angles be the exact same as the general shape or...?
by Lilyana Villa 3L
Sun Nov 10, 2019 10:39 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizability
Replies: 4
Views: 100

Re: Polarizability

Larger atoms have high polarizability because they tend to have more loosely held electrons while smaller atoms tend to hold electrons more closely. This makes it easier for their electrons to become distorted by a cation.
by Lilyana Villa 3L
Sun Nov 10, 2019 10:34 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: polarizability and polarizing power
Replies: 4
Views: 102

Re: polarizability and polarizing power

When a cation has high polarizing power, it has the ability to cause high electron distortion. The smaller the cation and the higher electronegativity it has, the more polarizing power it has. If you were to look at the s block, the cations on the topmost right will have the most polarizing power du...
by Lilyana Villa 3L
Sun Nov 10, 2019 10:23 pm
Forum: Lewis Structures
Topic: Bonds
Replies: 4
Views: 66

Re: Bonds

You must take into account how many electrons each atom needs in order to have an octet (keep in mind those who can have expanded octets), while also keeping track of the formal charge in order to make a Lewis structure with the lowest energy. Also something to keep in mind is that triple bonds are ...
by Lilyana Villa 3L
Tue Nov 05, 2019 7:18 pm
Forum: Lewis Structures
Topic: Homework Problem 2C. 3c
Replies: 1
Views: 47

Homework Problem 2C. 3c

3. Draw the Lewis structure, including typical contributions to the resonance structure (where appropriate, allow for the possibility of octet expansion, including double bonds in different positions), (c) chloric acid. For this question, I thought I did it right but then when I compared my answer t...
by Lilyana Villa 3L
Sun Nov 03, 2019 11:31 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 3
Views: 62

Re: Electron Configuration

I believe this is because electrons in the outermost shell (valence electrons) are easier to remove since electrons closer to the nucleus are more tightly held. Electrons in the highest orbital are in the outermost shell.
by Lilyana Villa 3L
Sun Nov 03, 2019 11:22 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 3
Views: 53

Re: Magnetic Quantum Number

The magnetic quantum number should always be plus or minus 1/2.
by Lilyana Villa 3L
Sun Nov 03, 2019 11:17 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Atomic Orbitals
Replies: 4
Views: 166

Atomic Orbitals

According to the Quantum World outline, we are supposed to be able to "describe the interpretation of atomic orbitals in terms of probability." What does this mean? Can some explain?
by Lilyana Villa 3L
Sun Nov 03, 2019 11:11 pm
Forum: Trends in The Periodic Table
Topic: Midterm Question Regarding Metals, Nonmetals, etc
Replies: 2
Views: 41

Midterm Question Regarding Metals, Nonmetals, etc

For the midterm, do we need to be able to identify if an element is a metal, nonmetal, metalloid, etc?
by Lilyana Villa 3L
Sun Nov 03, 2019 7:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework Problem 1E. 5
Replies: 2
Views: 62

Homework Problem 1E. 5

1E. 5) Which of the following statements are true for many-electron atoms? If false, explain why. (a) The effective nuclear charge Zeffe is independent of the number of electrons present in an atom. I know the answer is false but I can't explain why. Can someone explain why it's false?
by Lilyana Villa 3L
Sun Oct 27, 2019 10:37 pm
Forum: Resonance Structures
Topic: Arrangement of Atoms
Replies: 3
Views: 41

Arrangement of Atoms

How is formal charge used to predict the arrangement of atoms in a molecule?
by Lilyana Villa 3L
Sun Oct 27, 2019 10:32 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 3
Views: 73

Resonance Structures

Can someone give me an explanation on why we have to create resonance structures for some molecules instead of just a single lewis structure?
by Lilyana Villa 3L
Sun Oct 27, 2019 10:28 pm
Forum: Lewis Structures
Topic: Formal Charge [ENDORSED]
Replies: 6
Views: 82

Formal Charge [ENDORSED]

Can someone explain what formal charge is and how you calculate it? Thank you
by Lilyana Villa 3L
Sun Oct 27, 2019 10:25 pm
Forum: Resonance Structures
Topic: Kekule Structure
Replies: 2
Views: 41

Kekule Structure

Can someone explain to me what a kekule structure is?
by Lilyana Villa 3L
Sun Oct 27, 2019 9:55 pm
Forum: Lewis Structures
Topic: 2C.1
Replies: 2
Views: 45

Re: 2C.1

B and C are the radicals since they have an unpaired electron.
by Lilyana Villa 3L
Sun Oct 20, 2019 11:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Short Hand or Normal Way?
Replies: 3
Views: 91

Short Hand or Normal Way?

When writing electron configurations, are we allowed to write configurations in short hand or do we need to write out the whole configuration on assignments/test?
by Lilyana Villa 3L
Sun Oct 20, 2019 11:49 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spin
Replies: 8
Views: 124

Re: Electron Spin

According to Pauli Exclusion Principle, when two electrons do occupy one orbit, their spins must be paired. Electrons have parallel spins when they occupy different orbitals and must not be paired unless all of the orbitals have at least 1 electron in each.
by Lilyana Villa 3L
Sun Oct 20, 2019 11:36 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 1E.7
Replies: 3
Views: 53

Re: Homework 1E.7

I believe part C violates Aufbau's Principle because the 2s orbital must be occupied with 2 electrons with parallel spins before electrons can be arranged into the 2p orbital. There's 1 electron in the 2s orbital and 1 electron in the 2p orbital.
by Lilyana Villa 3L
Sun Oct 20, 2019 11:01 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Clarification on electron configuration
Replies: 5
Views: 72

Clarification on electron configuration

In his lecture, Lavelle said we only needed to know the electron configurations of atoms in a certain blocks. I know he said s-block and p-block, but I don't know how many rows of the d-block he said we are supposed to know. Does anyone remember?
by Lilyana Villa 3L
Sun Oct 20, 2019 10:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Excited State
Replies: 3
Views: 49

Excited State

How can you determine whether an atom is in an excited state based on the electron configuration?
by Lilyana Villa 3L
Sun Oct 13, 2019 11:53 pm
Forum: Properties of Light
Topic: 1B. 3
Replies: 2
Views: 51

1B. 3

I'm not 100% sure if my question falls under Properties of Light but here it is: From the following list of observations, select the one that best supports the idea that electromagnetic radiation has the properties of particles. Explain your reasoning. (a) Black-body radiation (b) electron different...
by Lilyana Villa 3L
Sun Oct 13, 2019 11:34 pm
Forum: Properties of Light
Topic: Lyman Series & Balmer Series
Replies: 4
Views: 59

Lyman Series & Balmer Series

What is the difference between the Balmer Series and Lyman Series?
by Lilyana Villa 3L
Sun Oct 13, 2019 11:18 pm
Forum: Properties of Light
Topic: Energy Equation
Replies: 3
Views: 40

Re: Energy Equation

I believe h is Planck's Constant
by Lilyana Villa 3L
Sun Oct 13, 2019 11:15 pm
Forum: Properties of Light
Topic: 1A. 11
Replies: 1
Views: 67

1A. 11

Q. A photon generated as a result of which of the following transitions in the hydrogen atom will have the greatest energy? Explain your answer. (a) From n=6 to n=5
I think I remember this from lecture but I don't understand the logic behind it. Can someone explain?
by Lilyana Villa 3L
Sun Oct 13, 2019 10:50 pm
Forum: Properties of Light
Topic: Homework Problem 1A. 15
Replies: 1
Views: 38

Homework Problem 1A. 15

Q. In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. I have no clue what I am supposed to do for this problem.
by Lilyana Villa 3L
Thu Oct 03, 2019 11:51 pm
Forum: SI Units, Unit Conversions
Topic: scientific notation
Replies: 7
Views: 82

Re: scientific notation

I think it's up to you if you want to put your answer in scientific notation or not. I don't think you'll be docked points if you do or don't use scientific notation, but it is probably recommended when you are dealing with very large or small numbers like 150,000 or 0.0005. My best answer is use yo...
by Lilyana Villa 3L
Thu Oct 03, 2019 11:42 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 3
Views: 92

Re: Formula Units

I believe formula units is just another word for atoms or molecules, depending on the context of the problem (like if the formula given depicts a molecule or an atom). I was confused on this question too about the formula units but when I checked the solutions manual, there wasn't anything in the gi...
by Lilyana Villa 3L
Thu Oct 03, 2019 11:33 pm
Forum: SI Units, Unit Conversions
Topic: Homework Problem E. 29
Replies: 3
Views: 74

Homework Problem E. 29

Q. A chemist measured out 8.61 g of copper (II) chloride tetrahydrate, CuCl2*4H2O. (a) How many moles of CuCl2*4H2O were measured out? b) How many moles of Cl- (the negative sign should be at the top) ions are present in the sample? I don't understand how you're supposed to do part B, can someone he...
by Lilyana Villa 3L
Thu Oct 03, 2019 10:58 pm
Forum: Empirical & Molecular Formulas
Topic: What decimal place to round to when taking masses from the Periodic Table?
Replies: 19
Views: 592

Re: What decimal place to round to when taking masses from the Periodic Table?

My recommendation is 2 to 3 decimal places. I don't think the professor is too strict on the rounding since not rounding at all is super excessive and could leave more room for error when typing it on the calculator to solve a problem.
by Lilyana Villa 3L
Thu Oct 03, 2019 6:57 pm
Forum: SI Units, Unit Conversions
Topic: Formula Names
Replies: 7
Views: 111

Formula Names

Does anyone know if we are required to know how to write out formulas when only given the formula name (ex. magnesium nitrate)? I never remember how to write out endings like sulfate and nitrate on the spot.

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