Search found 65 matches

by Daniel Lai
Sun Mar 17, 2019 12:58 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell concentration
Replies: 2
Views: 190

Re: cell concentration

Concentration cells have the same element on both sides just with different concentrations so there is not Ecell for standard conditions.
by Daniel Lai
Fri Mar 15, 2019 2:31 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Corrosion
Replies: 2
Views: 166

Re: Corrosion

The outline says to be familiar with industrial and biological examples so I'd just study it.
by Daniel Lai
Fri Mar 15, 2019 2:29 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 4J.5
Replies: 1
Views: 151

Re: 4J.5

When they say "of NH3," they mean one NH3.
by Daniel Lai
Fri Mar 15, 2019 2:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Delta N
Replies: 1
Views: 145

Re: Delta N

Yes. You are correct.
by Daniel Lai
Fri Mar 15, 2019 2:28 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration Cells
Replies: 2
Views: 41

Re: Concentration Cells

A higher concentration of cations means electrons are more drawn to that side.
by Daniel Lai
Fri Mar 15, 2019 2:27 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 7th edition 7D.1
Replies: 1
Views: 39

Re: 7th edition 7D.1

Use the equation for the difference in temperature for Arrhenius equations.
by Daniel Lai
Fri Mar 15, 2019 2:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams: Solids in different phases
Replies: 1
Views: 29

Re: Cell Diagrams: Solids in different phases

They will always be separated because solids can't mix.
by Daniel Lai
Fri Mar 15, 2019 2:22 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation and pH
Replies: 2
Views: 65

Re: Nernst Equation and pH

You can use Nernst Equation to find Q or K if it is at equilibrium. Then you can solve for [H+] if you are given other concentrations.
by Daniel Lai
Fri Mar 15, 2019 11:50 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: rules for Delta H
Replies: 1
Views: 168

Re: rules for Delta H

DeltaH = q at constant pressure. DeltaH doesn't correlate with w ever.
by Daniel Lai
Fri Mar 15, 2019 11:35 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalyst vs Intermediate
Replies: 1
Views: 55

Re: Catalyst vs Intermediate

Indeed. You are correct.
by Daniel Lai
Fri Mar 15, 2019 11:31 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Steady State?
Replies: 1
Views: 34

Re: Steady State?

We don't have to know that. We have to pre-equilibrium only.
by Daniel Lai
Fri Mar 15, 2019 11:29 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy
Replies: 2
Views: 223

Re: Gibbs Free Energy

Gibbs free energy of formation is 0 for elements in their standard states.
by Daniel Lai
Fri Mar 15, 2019 11:26 am
Forum: Zero Order Reactions
Topic: Zero-order reactions
Replies: 4
Views: 197

Re: Zero-order reactions

The units of the rate are always the same, mol/(L*s). k has the same units. because concentration doesn't matter. Half life is always in time units.
by Daniel Lai
Fri Mar 15, 2019 11:22 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: New Mechanisms
Replies: 1
Views: 37

Re: New Mechanisms

I believe it is only a single new mechanism because we are dealing with mechanisms of the whole reactions, not individual subreactions.
by Daniel Lai
Fri Mar 15, 2019 12:28 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: 6th Edition 15.61
Replies: 2
Views: 36

Re: 6th Edition 15.61

You take the difference of two Arrhenius equations. It's in the book.
by Daniel Lai
Fri Mar 15, 2019 12:28 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: 7D.5 Seventh Edition
Replies: 1
Views: 35

Re: 7D.5 Seventh Edition

I think the solution manual is wrong. The value you get should be lnK2/K1 = -0.59. And then you solve.
by Daniel Lai
Fri Mar 15, 2019 12:26 am
Forum: First Order Reactions
Topic: Linear plots problem 15.99
Replies: 1
Views: 29

Re: Linear plots problem 15.99

If it is a straight line on the graph, then it is linear.
by Daniel Lai
Fri Mar 15, 2019 12:26 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrehnius Equation
Replies: 2
Views: 37

Re: Arrehnius Equation

That particular equation won't be given. The derivation is just taking the difference of two Arrhenius equations.
by Daniel Lai
Fri Mar 15, 2019 12:25 am
Forum: First Order Reactions
Topic: Order of reactions plots
Replies: 2
Views: 43

Re: Order of reactions plots

For zero order, its A. For first order, its lnA. For second order, its 1/A
by Daniel Lai
Sat Mar 09, 2019 3:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M. 1 7th Edition
Replies: 2
Views: 41

6M. 1 7th Edition

A student was given a standard Cu(s)|Cu2+(aq) half-cell and another half-cell containing an unknown metal M in 1.00 M M(NO3)2 (aq) and formed the cell M(s)|M+||Cu2+(aq)|Cu(s). The cell potential was found to be -0.689 V. What is the value of E(M2+/M)? I don't understand how we're supposed to know wh...
by Daniel Lai
Wed Feb 20, 2019 1:09 pm
Forum: Ideal Gases
Topic: overall grade points
Replies: 2
Views: 82

Re: overall grade points

It sorta depends on how the rest of the class does. This class isn't curved but the grades are scaled. So, Lavelle will select a grade he thinks a B should be and then base everything around that score.
by Daniel Lai
Wed Feb 20, 2019 1:07 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous vs Not Spontaneous
Replies: 7
Views: 111

Re: Spontaneous vs Not Spontaneous

Negative delta G is spontaneous and positive is not spontaneous
by Daniel Lai
Tue Feb 12, 2019 11:33 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: work
Replies: 5
Views: 90

Re: work

It means work is being done on the system.
by Daniel Lai
Sun Feb 10, 2019 6:46 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Midterm Next Week
Replies: 6
Views: 130

Re: Midterm Next Week

The midterm covers till right before Gibbs Free Energy.
by Daniel Lai
Mon Jan 21, 2019 10:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: partial pressures vs. concentrations
Replies: 3
Views: 51

Re: partial pressures vs. concentrations

I think it depends on what they are asking for. If they do not specify, just make sure its clear which one you are finding.
by Daniel Lai
Mon Jan 21, 2019 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: autoprotolysis
Replies: 2
Views: 45

Re: autoprotolysis

Autoprotolysis is when water ionizes itself by donating a proton to another water molecule, but the liquid water remains neutral. This helps us derive the equation [H3O+][OH-] = Kw which is helpful in acid base calculations.
by Daniel Lai
Mon Jan 21, 2019 9:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Finding temperature
Replies: 1
Views: 40

Re: Finding temperature

I don't think you need to convert to concentrations because the answers seem to be in bars. You can just carry out the calculations in terms of pressure and Kp.
by Daniel Lai
Tue Jan 15, 2019 9:09 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous solution
Replies: 2
Views: 53

Re: Aqueous solution

Aqueous solutions are included in the calculation because compounds dissociate in solution.
by Daniel Lai
Fri Dec 07, 2018 11:44 pm
Forum: Bronsted Acids & Bases
Topic: Bases
Replies: 4
Views: 120

Bases

How do I know if something is a strong base?
by Daniel Lai
Fri Dec 07, 2018 1:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarizing Power for Na+, Mg2+, Li+, Be2+
Replies: 4
Views: 123

Re: Polarizing Power for Na+, Mg2+, Li+, Be2+

In the books section on ionic radius Li+ is bigger than Mg2+.
by Daniel Lai
Fri Dec 07, 2018 1:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarizing Power for Na+, Mg2+, Li+, Be2+
Replies: 4
Views: 123

Re: Polarizing Power for Na+, Mg2+, Li+, Be2+

Yea, but i thought we use ionic radius because these are ions?
by Daniel Lai
Fri Dec 07, 2018 1:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarizing Power for Na+, Mg2+, Li+, Be2+
Replies: 4
Views: 123

Polarizing Power for Na+, Mg2+, Li+, Be2+

Why is the polarizing power from least to greatest Na+, Mg2+, Li+, Be2+? I get why Na+ is the least and Be2+ is the greatest but I do not get why Li+ would be greater than Mg2+. Li+ is larger than Mg2+ according to the diagram of ionic radii in 1F.3 7th Edition and it has a lesser charge, so wouldn'...
by Daniel Lai
Fri Dec 07, 2018 12:47 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ranking strong acids and bases
Replies: 4
Views: 105

Re: Ranking strong acids and bases

I think greater polarity in the bond means they are more likely to dissociate.
by Daniel Lai
Fri Dec 07, 2018 12:46 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs & dipoles
Replies: 1
Views: 47

Re: Lone pairs & dipoles

They mainly affect the shape since lone pairs do not have polar properties.
by Daniel Lai
Fri Dec 07, 2018 12:44 pm
Forum: Naming
Topic: Polydentate Ligands
Replies: 2
Views: 65

Re: Polydentate Ligands

I think we need to know C2H8O2.
by Daniel Lai
Fri Dec 07, 2018 12:43 pm
Forum: Naming
Topic: Ligand Naming: -ido vs. -o
Replies: 2
Views: 62

Re: Ligand Naming: -ido vs. -o

I think either should be fine. I normally use -o because they use that in the answer key more.
by Daniel Lai
Sun Dec 02, 2018 5:03 pm
Forum: Hybridization
Topic: Hybridization
Replies: 5
Views: 104

Re: Hybridization

Tetrahedral is indeed always sp3.
by Daniel Lai
Sun Dec 02, 2018 5:01 pm
Forum: Hybridization
Topic: Hybridization
Replies: 3
Views: 97

Re: Hybridization

It depends. Different numbers of lone pairs can change the hybridization of the central atom but not change the shape. For example, a linear geometry can have 0 or 3 lone pairs.
by Daniel Lai
Sun Dec 02, 2018 4:31 pm
Forum: Hybridization
Topic: lone pairs
Replies: 20
Views: 308

Re: lone pairs

Lone pairs count as an area of electron density so they count for hybridization.
by Daniel Lai
Mon Nov 26, 2018 1:42 am
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 3
Views: 94

Re: Resonance

Basically. you have to draw a lewis structure first that fits the molecule. Then, see if it has resonance. It's difficult to just tell off the bat unless you have a lot of practice.
by Daniel Lai
Mon Nov 26, 2018 1:40 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: Polar Bonds
Replies: 3
Views: 77

Re: Polar Bonds

If they are opposite each other or have the same relative force of attraction, then they cancel out.
by Daniel Lai
Mon Nov 26, 2018 1:38 am
Forum: Student Social/Study Group
Topic: 4.21 Part c 6th edition
Replies: 1
Views: 78

Re: 4.21 Part c 6th edition

I do not think you have to unless it asks for it or all resonance structures.
by Daniel Lai
Sun Nov 18, 2018 2:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar vs Tetrahedral
Replies: 8
Views: 211

Re: Square Planar vs Tetrahedral

Square planar has two lone pairs that cause the 4 atoms surrounding the central atom to form a square. Tetrahedral has no lone pairs .
by Daniel Lai
Sun Nov 18, 2018 2:41 pm
Forum: Resonance Structures
Topic: Polar
Replies: 8
Views: 374

Re: Polar

Polarity does not affect it, only having the formal charges closest to 0 matters.
by Daniel Lai
Sun Nov 18, 2018 2:38 pm
Forum: Hybridization
Topic: sp3 hybridization
Replies: 6
Views: 108

Re: sp3 hybridization

Yes, I think so, because tetrahedral geometry has 4 areas of electron density.
by Daniel Lai
Sat Nov 03, 2018 8:18 pm
Forum: Resonance Structures
Topic: Polar
Replies: 8
Views: 374

Re: Polar

If the formal charges are close to 0, then you use that one.
by Daniel Lai
Sat Nov 03, 2018 8:14 pm
Forum: Resonance Structures
Topic: Radical formations
Replies: 1
Views: 60

Re: Radical formations

When there is an odd number of valence electrons, it will be a radical formation.
by Daniel Lai
Sat Nov 03, 2018 8:12 pm
Forum: Octet Exceptions
Topic: Formal charge
Replies: 7
Views: 176

Re: Formal charge

Yes, if you want to find the most stable form.
by Daniel Lai
Sun Oct 28, 2018 5:00 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 8
Views: 113

Re: Lewis Structures

The number of dots is the number of electrons for that element.
by Daniel Lai
Sun Oct 28, 2018 4:57 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 5
Views: 168

Re: Resonance Structures

Ozone is a good example for resonance. The double bond can be on either side of the central oxygen, so there are two resonance structures.
by Daniel Lai
Sun Oct 28, 2018 4:55 pm
Forum: Ionic & Covalent Bonds
Topic: the Octet rule
Replies: 21
Views: 408

Re: the Octet rule

Most elements try to go for a full octet or a half-filled octet.
by Daniel Lai
Thu Oct 25, 2018 11:32 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question about 4s and 3d orbitals
Replies: 1
Views: 52

Re: Question about 4s and 3d orbitals

The 4s orbital is only less in energy when there are no electrons in 3d. But, once 4s and 3d are filled, 4s is higher in energy, so it is the first to lose electrons.
by Daniel Lai
Tue Oct 23, 2018 12:46 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.55 6th edition
Replies: 1
Views: 30

Re: Question 1.55 6th edition

I think your answer is right. We went over this question in my discussion and we got 1.08*10^10 1/s.
by Daniel Lai
Sat Oct 20, 2018 5:09 pm
Forum: *Shrodinger Equation
Topic: Book Example 1.8:
Replies: 4
Views: 132

Re: Book Example 1.8:

I would not think so since nothing like that was covered in class.
by Daniel Lai
Sat Oct 20, 2018 5:06 pm
Forum: Properties of Light
Topic: Atomic Spectra
Replies: 3
Views: 94

Re: Atomic Spectra

I think the one line represents the particular wavelength of light.
by Daniel Lai
Sat Oct 20, 2018 5:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Topics We Need to Know for the Test [ENDORSED]
Replies: 5
Views: 170

Re: Topics We Need to Know for the Test [ENDORSED]

We don't need to know electron configuration or periodic trends.
by Daniel Lai
Thu Oct 11, 2018 10:47 pm
Forum: Properties of Light
Topic: Black Body Radiation
Replies: 4
Views: 77

Re: Black Body Radiation

Don't worry about Black Body Radiation. It's not required knowledge for this class.
by Daniel Lai
Thu Oct 11, 2018 10:44 pm
Forum: Empirical & Molecular Formulas
Topic: M19
Replies: 1
Views: 156

M19

This question was really hard. I looked at the books method, and it didn't make any sense. I did it a different way by determining the coefficients of the other terms using empirical method. Did anyone else do it this way???
by Daniel Lai
Wed Oct 10, 2018 6:22 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Spectral line energy
Replies: 1
Views: 26

Re: Spectral line energy

I think it's negative because we are viewing the energy relative to the electron. So, the electron is losing energy, thus the change in energy is negative.
by Daniel Lai
Sun Oct 07, 2018 9:11 pm
Forum: Significant Figures
Topic: Calculating process
Replies: 5
Views: 404

Re: Calculating process

I agree.
by Daniel Lai
Thu Oct 04, 2018 3:15 pm
Forum: Significant Figures
Topic: Decimal point
Replies: 14
Views: 277

Re: Decimal point

Basically, zeroes before the decimal point with the decimal point behind them and zeroes following the decimal point are significant. The only zeroes that aren't significant are zeroes in a number like 120 where they are no decimal points.
by Daniel Lai
Sun Sep 30, 2018 5:36 pm
Forum: Balancing Chemical Reactions
Topic: Short cuts/methods for balancing equations
Replies: 15
Views: 202

Re: Short cuts/methods for balancing equations

Generally, I start by finding the compounds with single atoms in its formula. So, for example, if I see C6H8O6 on one side and I see CO2 on the other, I'll start by putting a 6 in front of the CO2.

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