Search found 60 matches

Fri Mar 15, 2019 2:31 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: 48

Re: Concentration Cells

Because there are more cations, the electrons will tend towards that side.
Fri Mar 15, 2019 2:30 pm
Forum: General Rate Laws
Topic: rate laws
Replies: 6
Views: 103

Re: rate laws

it is a common misconception that they are. However, the stoichiometric coefficients are not used in the rate law. It should always be given or we will have experiments to use them.
Fri Mar 15, 2019 2:27 pm
Forum: Zero Order Reactions
Topic: Zero-order reactions
Replies: 4
Views: 220

Re: Zero-order reactions

When we are calculating the units for zero order reaction, the only thing that we need is the units of the rate, which is mol/L*s
Wed Mar 06, 2019 4:51 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Galvanic Cells
Replies: 4
Views: 89

Re: Galvanic Cells

They work reversibly because the reactions are spontaneous. Being reversible allows the cell to produce energy for work.
Wed Mar 06, 2019 4:49 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: E cell
Replies: 5
Views: 110

Re: E cell

E^o is the standard reduction potential, which is essentially the cell potential at STP under ideal conditions.

E is the cell potential that changes based on the "nonstandard" conditions.
Wed Mar 06, 2019 4:37 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: n in Nernst
Replies: 4
Views: 112

Re: n in Nernst

We are able to determine n in this equation through the number of electrons that are transferred. This is seen through the half reactions that we do.
Fri Mar 01, 2019 2:20 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Significant Figures
Replies: 2
Views: 65

Re: Significant Figures

We use the minimum number of sig figs that are given at the beginning of the problem. This is the number that we should be using.
Fri Mar 01, 2019 2:18 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding n for the equation ΔG⁰=-nFE⁰
Replies: 8
Views: 170

Re: Finding n for the equation ΔG⁰=-nFE⁰

We do this by doing the half reactions and then balancing the equations. Whatever the number of electrons added is the n of our equation.
Fri Mar 01, 2019 2:17 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Finding Gibbs Free Energy in Conceptual Situations
Replies: 2
Views: 57

Re: Finding Gibbs Free Energy in Conceptual Situations

In order to do this, you must conceptualize it and try to gauge an idea of how H, T, and S interact by using the formula loosely.
Fri Feb 22, 2019 2:34 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G=0 at equilibrium
Replies: 4
Views: 152

Re: Delta G=0 at equilibrium

Gibbs free energy is the free energy in a system. When it is 0, there can be no gain or loss of energy.
Fri Feb 22, 2019 2:32 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity
Replies: 8
Views: 192

Re: Spontaneity

When delta G is negative, it is spontaneous. When it is positive, it is not.
Fri Feb 22, 2019 2:31 pm
Forum: Balancing Redox Reactions
Topic: Number of electrons
Replies: 5
Views: 100

Re: Number of electrons

We want to balance the number of electrons on both sides. In order to do this, we must add electrons in the half reactions. They should cancel out when added.
Fri Feb 15, 2019 2:15 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Liquid and moles
Replies: 8
Views: 348

Re: Liquid and moles

We do not calculate ICE tables with liquids and solids as they have no effect on the molar concentrations in those calculations. So H20 would not be counted if it is a liquid.
Fri Feb 15, 2019 2:14 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy equations
Replies: 8
Views: 335

Re: Entropy equations

I believe when doing these types of problems, the situations will be described and we can do it from there.
Fri Feb 15, 2019 2:13 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: using gas constant R
Replies: 4
Views: 101

Re: using gas constant R

You use 3/2R for when volume is constant and then 5/2R and 3R depending on the type or molecule. You use 5/2R when pressure is constant and then 7/2R and 4R for each subsequent shape.
Wed Feb 06, 2019 4:34 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Constant numbers
Replies: 4
Views: 136

Re: Constant numbers

All constants that we need to know will be listed on the sheet that we are given on test day.
Wed Feb 06, 2019 4:32 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed systems
Replies: 6
Views: 125

Re: closed systems

Closed systems can have either constant pressure and constant volume. There may also be times where both are constant.
Wed Feb 06, 2019 4:30 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Bomb Calorimeter
Replies: 3
Views: 93

Re: Bomb Calorimeter

A bomb calorimeter is closed system
Fri Feb 01, 2019 1:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Enthalpy
Replies: 6
Views: 100

Re: Enthalpy

Endothermic is using heat, so delta H would be positive, whereas exothermic reactions lose heat so it'll be a negative delta H.
Fri Feb 01, 2019 1:16 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capactiy
Replies: 5
Views: 112

Heat Capactiy

Why is heat capacity referred to as an extensive property?
Fri Feb 01, 2019 1:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpies
Replies: 5
Views: 84

Re: Enthalpies

Enthalpy is essentially the change in the internal heat of the system.
Sun Jan 27, 2019 1:48 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to ignore change in Acid
Replies: 5
Views: 122

Re: When to ignore change in Acid

The standard way when using an ICE calculation, is to believe that if K is less than something x10^-3, we can assume it is 0 as it will have little to no effect on the calculation.
Sun Jan 27, 2019 1:46 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: units for standard reaction enthalpy
Replies: 2
Views: 42

Re: units for standard reaction enthalpy

It may seem confusing, but the standard unit is kJ/mol and not kJ.
Sun Jan 27, 2019 1:45 pm
Forum: Ideal Gases
Topic: atm vs. bar?
Replies: 23
Views: 491

Re: atm vs. bar?

I believe that in the calculations that we are doing, we should use the unit that they give us... otherwise, I think they are interchangeable.
Mon Jan 21, 2019 4:36 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Acids and Bases
Replies: 3
Views: 85

Re: Acids and Bases

Arrhenius acids form H+ in water bases form OH
Lewis Definition regards electrons and if they accept them its an acid, if they donate electrons its a base
Bronsted definition regards donating protons are acids and those that accept protons are bases
Mon Jan 21, 2019 4:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure
Replies: 7
Views: 145

Re: Pressure

you only include gases and aqueous solutions to calculate the pressure
Mon Jan 21, 2019 4:31 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gases
Replies: 7
Views: 165

Re: Inert Gases

inert gases essentially have no effect on the reaction because it does not affect the concentrations of these gases.
Sun Jan 13, 2019 3:35 pm
Forum: Ideal Gases
Topic: Concentration or Partial Pressure
Replies: 13
Views: 215

Re: Concentration or Partial Pressure

By looking at the reactants and products and seeing what you have is the first step in solving the problem. The question will usually say what to use to calculate the K value.
Sun Jan 13, 2019 3:33 pm
Forum: Ideal Gases
Topic: Ideal Gases
Replies: 7
Views: 106

Re: Ideal Gases

An ideal gas is a theoretical idea that the gas is in a simple form so that it allows for easier calculation. I think most problems that we are given will only consist of ideal gases.
Sun Jan 13, 2019 3:29 pm
Forum: Ideal Gases
Topic: bar or atm
Replies: 8
Views: 174

Re: bar or atm

I believe professor Lavelle stated that in class they can be used interchangeably and that they are so close in value,
Wed Dec 05, 2018 1:43 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 1
Views: 77

Ligands

Are there any ligand structures that we need to memorize where the elements are not easily distinguishable?
Wed Dec 05, 2018 1:41 am
Forum: Naming
Topic: Cyanide
Replies: 6
Views: 136

Re: Cyanide

I also believe they are the same, but cyano seems to be what professor Lavelle is using so I'd use that.
Wed Dec 05, 2018 1:39 am
Forum: Naming
Topic: Charge of Ligands
Replies: 1
Views: 50

Charge of Ligands

How do we determine the charge of each ligand?
Sat Dec 01, 2018 3:19 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Amines and strength of acid
Replies: 4
Views: 79

Re: Amines and strength of acid

Amines are some of the most basic molecules out there as they aren't entirely ionized when placed in water.
Sat Dec 01, 2018 3:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar Molecules
Replies: 12
Views: 204

Re: Polar Molecules

Polar molecules will have a net dipole moment as there is asymmetrical. Nonpolar molecules are mostly symmetrical and have no dipole moment at all as they cancel out.
Sat Dec 01, 2018 3:15 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Induced dipoles
Replies: 7
Views: 313

Re: Induced dipoles

In short, an induced dipole is when a nonpolar molecule binds with a polar molecule as the dipoles attract it.
Sun Nov 18, 2018 10:11 pm
Forum: Sigma & Pi Bonds
Topic: Visualizing sigma and pi bonds
Replies: 7
Views: 184

Re: Visualizing sigma and pi bonds

Sun Nov 18, 2018 10:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Octahedral to Square Planar
Replies: 7
Views: 118

Re: Octahedral to Square Planar

A square planar shape is essentially an octahedral, but 2 of the 6 surrounding atoms replaced by two lone pairs and create this new shape.
Sun Nov 18, 2018 10:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lecture VSEPR
Replies: 2
Views: 99

Re: Lecture VSEPR

We can easily measure the qualitative properties of a structure as the shape or polarity. However, exact bond angles can't be measured directly, which is what I think he means by we can't measure it quantitatively.
Sun Nov 18, 2018 9:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape Patterns
Replies: 5
Views: 121

Re: Molecular Shape Patterns

Unfortunately, there doesn't seem to be a pattern. I think we just have to memorize it at this point.
Sun Nov 18, 2018 9:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs
Replies: 11
Views: 205

Re: lone pairs

Lone pairs are able to change the bond angle and shape as they push the other bonds around.
Sun Nov 18, 2018 9:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles Between the Same shape
Replies: 6
Views: 139

Re: Bond Angles Between the Same shape

Bond Angles are always the same when the shapes are identical in structure.
Thu Nov 08, 2018 5:40 pm
Forum: Bond Lengths & Energies
Topic: MIDTERM Bond Length Question
Replies: 15
Views: 367

Re: MIDTERM Bond Length Question

To be honest, I just took the averages of the two lengths as the structures need to be balanced, so it was 130.
Thu Nov 08, 2018 5:37 pm
Forum: Bond Lengths & Energies
Topic: Formula/ Memorization of Bond lengths?
Replies: 3
Views: 74

Formula/ Memorization of Bond lengths?

Is there a formula to calculate the bond lengths, or will we have to memorize each one?
Thu Nov 08, 2018 5:35 pm
Forum: Dipole Moments
Topic: Induced Dipole
Replies: 4
Views: 99

Induced Dipole

I'm pretty confused as to what an induced dipole is, would anyone care to explain?
Thu Nov 01, 2018 8:07 pm
Forum: Ionic & Covalent Bonds
Topic: Ionization Energy
Replies: 2
Views: 38

Ionization Energy

Which period trend dictates the levels of ionization energy so we can draw the lewis structure?
Thu Nov 01, 2018 8:05 pm
Forum: Sigma & Pi Bonds
Topic: Easy way of remembering the difference
Replies: 6
Views: 207

Easy way of remembering the difference

Does anyone know an easy way to tell the difference between the bonds because they are very confusing into what they are?
Thu Nov 01, 2018 8:02 pm
Forum: Resonance Structures
Topic: Most Stable Configuration
Replies: 11
Views: 292

Most Stable Configuration

If asked to draw the most stable configuration for a resonance structure, how do we know which configuration is the most stable?
Fri Oct 26, 2018 11:46 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Replies: 5
Views: 153

Is there a formula we can use to calculate the number of nodal/radial planes?
Fri Oct 26, 2018 11:44 am
Forum: Einstein Equation
Topic: Units
Replies: 6
Views: 396

Re: Units

Units 100% should be memorized. It makes solving the problems much quicker and will allow you to finish earlier without having to think about it. We will not be given these on the tests
Fri Oct 26, 2018 11:42 am
Forum: DeBroglie Equation
Topic: momentum of light
Replies: 2
Views: 120

Re: momentum of light

Momentum is often referred to as the mass times acceleration of a function. However, even though photons are massless, light has wavelength properties that we can measure momentum from as there are properties that we can measure/ will be given.
Wed Oct 17, 2018 11:10 pm
Forum: Einstein Equation
Topic: Question on Midterm
Replies: 7
Views: 382

Re: Question on Midterm

I'm pretty sure as long as we convert to the significant figures and convert at the end, it should all be fine.
Wed Oct 17, 2018 11:08 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Difference in orbitals
Replies: 3
Views: 89

Re: Difference in orbitals

f-orbitals are some of the most complex graphs and we don't need to how to graph them as of now.
Wed Oct 17, 2018 10:56 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Plane
Replies: 2
Views: 37

Re: Nodal Plane

A nodal plane is the space/area around the nucleus that splits up the lobes and contains no electrons.
Thu Oct 11, 2018 2:55 pm
Forum: Photoelectric Effect
Topic: φ
Replies: 1
Views: 49

φ

What exactly does the symbol φ stand for? How would you measure this?
Thu Oct 11, 2018 2:53 pm
Forum: Properties of Light
Topic: Problem 1.3 6th ed.
Replies: 3
Views: 75

Re: Problem 1.3 6th ed.

I believe the answer is C as the frequency decreases, so does the slope of the wave.
Thu Oct 11, 2018 2:41 pm
Forum: Properties of Light
Topic: Photon energy
Replies: 3
Views: 85

Photon energy

How do we know when a photon has enough energy to eject an electron?
Fri Oct 05, 2018 4:09 pm
Forum: Significant Figures
Topic: Rounding off/sig figs during steps of a calculation
Replies: 4
Views: 112

Re: Rounding off/sig figs during steps of a calculation

I would suggest using the parenthesis in your calculator to surround the fraction so the number is always exact and never rounded.
Thu Oct 04, 2018 5:42 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Equations
Replies: 2
Views: 64

Balancing Chemical Equations

Why do we have to calculate the net number of moles produced in a balanced chemical reaction?
Thu Oct 04, 2018 1:04 am
Forum: Significant Figures
Topic: Decimal point
Replies: 14
Views: 318

Re: Decimal point

These both have the same amount of significant figures. During one of the lectures, Dr. Lavelle had stated that significant figures are easily understandable when you put them into scientific notation. For example, these two numbers(125 and 125.) are both 1.25 * 10^2 and have 3 significant figures.