Search found 78 matches

by Giselle Littleton 1F
Tue Mar 17, 2020 8:23 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Work+Gibbs Free Energy
Replies: 3
Views: 22

Work+Gibbs Free Energy

How does work relate to Gibbs Free Energy?
by Giselle Littleton 1F
Sun Mar 15, 2020 4:33 pm
Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
Topic: Concentrations
Replies: 2
Views: 18

Concentrations

How is the voltage of a galvanic cell affected by anode/cathode concentration?
by Giselle Littleton 1F
Sun Mar 15, 2020 4:24 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reverse reaction rate?
Replies: 4
Views: 24

Reverse reaction rate?

How do you find the reverse reaction rate of a reaction?
by Giselle Littleton 1F
Sun Mar 15, 2020 4:21 pm
Forum: General Rate Laws
Topic: Overall Order
Replies: 6
Views: 20

Overall Order

How do you get the overall order of a reaction?
by Giselle Littleton 1F
Sun Mar 15, 2020 4:16 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Fast Reactions
Replies: 4
Views: 17

Fast Reactions

Why aren't fast reactions included in rate laws?
by Giselle Littleton 1F
Sun Mar 08, 2020 9:57 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Instantaneous Rate
Replies: 13
Views: 57

Instantaneous Rate

How does the instantaneous rate react as the reaction proceeds?
by Giselle Littleton 1F
Sun Mar 08, 2020 9:56 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 8
Views: 32

Catalysts

How do catalysts lower the activation energy of the transition state?
by Giselle Littleton 1F
Sun Mar 08, 2020 9:55 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Temperature
Replies: 4
Views: 17

Temperature

How is temperature related to the activation energy?
by Giselle Littleton 1F
Sun Mar 08, 2020 9:53 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Molecularity and rate laws
Replies: 5
Views: 23

Molecularity and rate laws

How is molecularity related to the order of a reaction rate law?
by Giselle Littleton 1F
Sun Mar 08, 2020 9:50 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Molecularity
Replies: 3
Views: 13

Molecularity

What is molecularity?
by Giselle Littleton 1F
Fri Feb 28, 2020 10:33 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Is it spontaneous?
Replies: 4
Views: 22

Is it spontaneous?

How does a chemical reaction proceed when the Ecell=0 and K=0? Is it spontaneous or not?
by Giselle Littleton 1F
Fri Feb 28, 2020 10:26 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Spontaneous reactions
Replies: 6
Views: 23

Spontaneous reactions

Does the chemical reaction being spontaneous increase or decrease cell potential?
by Giselle Littleton 1F
Fri Feb 28, 2020 10:25 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: EMF
Replies: 1
Views: 15

EMF

How does electromotive force relate to cell potential?
by Giselle Littleton 1F
Tue Feb 18, 2020 1:09 pm
Forum: Balancing Redox Reactions
Topic: Balancing Basic Solutions
Replies: 2
Views: 27

Balancing Basic Solutions

For a basic solution, why do we balance H by adding H20 to one side and OH- to the other?
by Giselle Littleton 1F
Tue Feb 18, 2020 1:05 pm
Forum: Balancing Redox Reactions
Topic: Finding charge
Replies: 2
Views: 20

Finding charge

How can you know the charge of a compound in a redox reaction?
by Giselle Littleton 1F
Wed Feb 12, 2020 9:29 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: thermodynamically stable
Replies: 6
Views: 44

Re: thermodynamically stable

Thermodynamically stable means that the reaction is spontaneous. Thus, when △G is negative, it is thermodynamically stable.
by Giselle Littleton 1F
Wed Feb 12, 2020 9:23 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong Acids
Replies: 2
Views: 23

Re: Strong Acids

Strong acids also have large Ka values and small pKa values.
by Giselle Littleton 1F
Wed Feb 12, 2020 9:16 am
Forum: Calculating Work of Expansion
Topic: Determining Expansion Work
Replies: 4
Views: 38

Determining Expansion Work

How can you tell whether a system does expansion work by just looking at the gas moles on both sides of the equation?
by Giselle Littleton 1F
Wed Feb 12, 2020 9:11 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpy
Replies: 2
Views: 27

Bond Enthalpy

Why do we subtract the bond enthalpy of the products from the reactants?
by Giselle Littleton 1F
Wed Feb 12, 2020 9:07 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Delta S
Replies: 6
Views: 51

Re: Delta S

The change in entropy of the surroundings is the same as the change in entropy of the system.
by Giselle Littleton 1F
Sat Feb 08, 2020 11:37 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy of the system and surrounding
Replies: 2
Views: 26

Re: Entropy of the system and surrounding

I visualized this in terms of an ice cube in a warm cup of water. Two things are happening in this process. The ice cube is melting, so q for the ice cube would be positive beccause it is absorbing energy. The warm water is getting colder, so q would be negative, because it is releasing energy. △Sto...
by Giselle Littleton 1F
Sat Feb 08, 2020 11:26 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeter Differences
Replies: 2
Views: 24

Re: Bomb Calorimeter Differences

From the homework, I've noticed that these types of question tend to ask you to find q, △H ,or, △U. I find it helpful to keep in mind that for constant volume, △U=q and for constant pressure, △H=q.
by Giselle Littleton 1F
Thu Feb 06, 2020 2:14 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 4
Views: 33

Bond Enthalpies

I notice that in some problems from the homework, specific bonds within molecules aren't included when calculating the bond enthalpies. Why is that and how can I watch out for those that I should not include?
by Giselle Littleton 1F
Thu Feb 06, 2020 2:11 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Elements/Standard Enthalpies of Formation
Replies: 1
Views: 19

Elements/Standard Enthalpies of Formation

Why aren't elements included when calculating the standard enthalpy of formation?
by Giselle Littleton 1F
Mon Feb 03, 2020 1:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Thermodynamic Stability
Replies: 1
Views: 13

Thermodynamic Stability

Why is a compound considered to be thermodynamically stable when △G°is negative and thermodynamically unstable when △G°is positive?
by Giselle Littleton 1F
Sun Feb 02, 2020 10:29 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Changes in pressure
Replies: 2
Views: 26

Re: Changes in pressure

Lower pressure leads to an increase in positional disorder of the atoms as a gas is compressed.
by Giselle Littleton 1F
Sun Feb 02, 2020 10:25 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Second Law and Biological Examples
Replies: 1
Views: 18

Second Law and Biological Examples

Please explain the Second Law of Thermodynamics in relation to biological and organic reactions.
by Giselle Littleton 1F
Sun Feb 02, 2020 10:16 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work and Heat
Replies: 2
Views: 11

Work and Heat

Why aren't work and heat state functions?
by Giselle Littleton 1F
Sun Feb 02, 2020 10:11 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Adiabatic Wall
Replies: 3
Views: 17

Adiabatic Wall

Does an adiabatic affect how much energy a reaction gives off?
by Giselle Littleton 1F
Sun Feb 02, 2020 10:07 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: State Property
Replies: 5
Views: 29

State Property

What is the relationship between state property and enthalpy?
by Giselle Littleton 1F
Fri Jan 24, 2020 10:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Irreversible Expansion
Replies: 4
Views: 31

Irreversible Expansion

What is irreversible expansion?
by Giselle Littleton 1F
Fri Jan 24, 2020 10:03 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Reversible Expansion
Replies: 2
Views: 18

Reversible Expansion

What is reversible expansion?
by Giselle Littleton 1F
Wed Jan 22, 2020 1:22 pm
Forum: Phase Changes & Related Calculations
Topic: enthalpy
Replies: 2
Views: 25

Re: enthalpy

Steam causes severe burns because the enthalpy of vaporization is really large for water, and thus steam carries a lot of heat from the 100 degree Celsius point.
by Giselle Littleton 1F
Tue Jan 21, 2020 6:57 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Second Ionization in Polyprotic Acid Solutions
Replies: 2
Views: 15

Second Ionization in Polyprotic Acid Solutions

Why is the second ionization ignored if Ka2<Ka1?
by Giselle Littleton 1F
Tue Jan 21, 2020 6:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference between K and Kc
Replies: 1
Views: 13

Re: Difference between K and Kc

K refers to the ratio of products to a reactants in a chemical equilibrium equation when using only partial pressures. However, if you have an equation with an aqueous solution, Kc would be used because you would be determining the ratio of products to reactants in molar concentrations. I would reco...
by Giselle Littleton 1F
Fri Jan 17, 2020 7:48 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: inert gas added
Replies: 4
Views: 19

Re: inert gas added

Adding an inert gas does not have any effect because the volume doesn't change. To shift a reaction the volume must be decreased, and consequently, the pressure will increase.
by Giselle Littleton 1F
Fri Jan 17, 2020 7:43 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: K comparison
Replies: 4
Views: 39

Re: K comparison

If a K is less than 10^-3, it just means that the reactants are strongly favored and if K is greater than 10^3 it means that the products are strongly favored.
by Giselle Littleton 1F
Wed Jan 15, 2020 8:55 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Base Equilibria
Replies: 4
Views: 43

Re: Acids and Base Equilibria

Additionlly, a strong acid wil have a small pKa value and a strong base will have a small pKb value.
by Giselle Littleton 1F
Tue Jan 14, 2020 8:03 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak Bases and Acids
Replies: 2
Views: 14

Weak Bases and Acids

Is there some point that the Ka and Kb values reach for an acid or base to be considered weak?
by Giselle Littleton 1F
Mon Jan 13, 2020 8:51 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: intermediate values of K
Replies: 3
Views: 20

Re: intermediate values of K

And if K<1, the reaction favors reactants, with 10^-3 being the point at which the reaction strongly favors reactants. K>1 means that the reaction favors products with 10^3 being the point at which the reaction strongly favors products.
by Giselle Littleton 1F
Fri Jan 10, 2020 9:38 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and relation of [R] to [P]
Replies: 5
Views: 54

Q and relation of [R] to [P]

For Q<K, why is [R]>[P] and for Q>K, why is [P]>[R]?
by Giselle Littleton 1F
Thu Jan 09, 2020 5:06 pm
Forum: Ideal Gases
Topic: K based on phases
Replies: 4
Views: 31

Re: K based on phases

You can find the equilibrium constant for reactants and products if they are gas and/or aqueous.
by Giselle Littleton 1F
Wed Jan 08, 2020 1:13 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Reaction Quotient > Equilibrium Constant
Replies: 4
Views: 37

Re: Reaction Quotient > Equilibrium Constant

I think of it in terms of the reaction needing to accommodate the decrease in reactant concentration in relation to the concentration of the products, so it needs more reactants so that the equilibrium constant is retained.
by Giselle Littleton 1F
Tue Jan 07, 2020 4:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K
Replies: 13
Views: 107

Re: Q vs K

The reaction quotient Q describes the ratio of products to reactants when the reaction in a non-equilibrium state. K describes the same thing only when the reaction is at equilibrium.
by Giselle Littleton 1F
Mon Jan 06, 2020 1:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining Equilibrium Reaction Direction
Replies: 4
Views: 56

Determining Equilibrium Reaction Direction

When determining the direction of an equilibrium reaction, how do you know whether to use 10^3/10^-3 or 1 as a comparison to K? I've seen both 1 and 10^3/10^-3 being used.
by Giselle Littleton 1F
Mon Jan 06, 2020 1:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Determining Equilibrium Reaction Direction
Replies: 3
Views: 53

Determining Equilibrium Reaction Direction

When determining the direction of an equilibrium reaction, how do you know whether to use 10^3/10^-3 or 1 as a comparison to K? I've seen both 1 and 10^3/10^-3 being used.
by Giselle Littleton 1F
Sun Nov 24, 2019 5:08 pm
Forum: Lewis Acids & Bases
Topic: Lewis and Bronsted
Replies: 5
Views: 43

Re: Lewis and Bronsted

Lewis and Bronsted acids and bases are interchangeable. A Lewis acid accepts an electron pair and a Bronsted acid donates a proton. Both types are acids whose overall charges decrease. A Lewis base donates an electron pair and a Bronsted base accepts a proton. So, the charges of both types increase.
by Giselle Littleton 1F
Sun Nov 24, 2019 5:02 pm
Forum: Lewis Acids & Bases
Topic: carboxyl group COOH
Replies: 3
Views: 30

Re: carboxyl group COOH

The H+ ion in the compound can be donated to a base.
by Giselle Littleton 1F
Sun Nov 24, 2019 4:57 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Why are inorganic acids stronger?
Replies: 8
Views: 71

Re: Why are inorganic acids stronger?

Inorganic compounds are more likely to completely deprotonate.
by Giselle Littleton 1F
Sun Nov 24, 2019 4:53 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation states
Replies: 6
Views: 43

Re: Oxidation states

Also, when you're naming the complex, it might be helpful to find the determine the overall charge first.
by Giselle Littleton 1F
Sun Nov 24, 2019 4:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelating Complex
Replies: 3
Views: 40

Chelating Complex

How can you tell if a compound is a chelate by just looking at its formula?
by Giselle Littleton 1F
Fri Nov 08, 2019 3:13 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Bonds vs Shapes [ENDORSED]
Replies: 4
Views: 315

Re: Bonds vs Shapes [ENDORSED]

The more bonds a molecule has, the harder it is to break apart. So the boiling point of a molecule would increase if there were more bonds because it takes more energy to break the molecule apart.
by Giselle Littleton 1F
Fri Nov 08, 2019 3:10 pm
Forum: Octet Exceptions
Topic: Octet Rule exceptions
Replies: 14
Views: 159

Re: Octet Rule exceptions

Some of the elements in the d block have unfilled orbitals. So it depends on the orbital.
by Giselle Littleton 1F
Fri Nov 08, 2019 3:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VESPR
Replies: 5
Views: 54

Re: VESPR

The addition of a lone pair creates repulsion between the electrons, thus changing the bond angles in a way in which minimal energy is used.
by Giselle Littleton 1F
Fri Nov 08, 2019 2:59 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 11
Views: 83

Re: Bond lengths

The bond lengths are all the same in the resonance structure because the structures all approximate the actual structure that is supposed to form. That is, the resonance structures are a mix of structures close to the actual structure.
by Giselle Littleton 1F
Fri Nov 08, 2019 2:56 pm
Forum: Lewis Structures
Topic: Favorable Bonds
Replies: 5
Views: 55

Re: Favorable Bonds

To form an octet, oxygen needs 2 electrons while nitrogen needs 3. But unless the atom(s) they're bonded to is specified, the more bonds the harder it is to break the molecule.
by Giselle Littleton 1F
Mon Oct 21, 2019 8:16 pm
Forum: Trends in The Periodic Table
Topic: Effective Nuclear Charge
Replies: 7
Views: 46

Effective Nuclear Charge

Can anyone explain what effective nuclear charge means and how it contributes to a decrease in atomic radius across a period?
by Giselle Littleton 1F
Sun Oct 20, 2019 7:47 pm
Forum: Trends in The Periodic Table
Topic: Trends in Electron Affinity
Replies: 3
Views: 56

Re: Trends in Electron Affinity

As you go up and to the right, electron affinity increases as the atoms get more electronegative and are thus more likely to attract electrons. For example, oxygen is more electronegative and more likely to attract electrons than hydrogen. Oxygen is farther to the right in the periodic table and hog...
by Giselle Littleton 1F
Sun Oct 20, 2019 7:42 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals and Quantum Levels
Replies: 4
Views: 48

Re: Orbitals and Quantum Levels

The electron's path just gets further from the nucleus.
by Giselle Littleton 1F
Sun Oct 20, 2019 7:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Atomic orbitals
Replies: 5
Views: 56

Re: Atomic orbitals

The probability of electron density is the likelihood that an electron is in a certain location or orbital.
by Giselle Littleton 1F
Sun Oct 20, 2019 7:36 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Problem 1a.11
Replies: 3
Views: 50

Re: Problem 1a.11

What's common between them is that the electrons move closer to the nucleus in every case. So, they always move to lower energy levels.
by Giselle Littleton 1F
Sun Oct 20, 2019 7:31 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: s-, p-, d- ,f- orbitals
Replies: 10
Views: 102

Re: s-, p-, d- ,f- orbitals

"2" describes the shell, "p" describes the subshell, while the subscripts (x,y,z) tell you what axis.
by Giselle Littleton 1F
Sun Oct 13, 2019 10:55 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect
Replies: 3
Views: 40

Re: Photoelectric Effect

Light also has particle-like properties as a stream of electromagnetic energy consisting of photons. Light can be absorbed or emitted in quantized or discrete values.
by Giselle Littleton 1F
Sun Oct 13, 2019 10:50 pm
Forum: Photoelectric Effect
Topic: Frequency vs. Amplitude: Intensity?
Replies: 3
Views: 31

Re: Frequency vs. Amplitude: Intensity?

Amplitude contributes to the intensity of a wave. Thus amplitude has no contribution to the photoelectric effect because of its relation to intensity. Frequency is most important to the photoelectric effect.
by Giselle Littleton 1F
Sun Oct 13, 2019 10:47 pm
Forum: Properties of Electrons
Topic: Energy levels
Replies: 4
Views: 57

Re: Energy levels

The energy levels are infinite. What separates the elements is that specific amounts of energy are required for different atoms to absorb or emit photons.
by Giselle Littleton 1F
Sun Oct 13, 2019 10:31 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: When to use the Bohr Frequency Condition?
Replies: 3
Views: 37

Re: When to use the Bohr Frequency Condition?

The Bohr frequency condition demonstrates an electron's transition between energy levels. Differences in energy levels are given off as photons and only photons of certain energy are given off exactly matching the energy level difference.
by Giselle Littleton 1F
Sun Oct 13, 2019 10:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 2060

Re: Rydberg equation [ENDORSED]

The Rydberg equation is used to find the wavelength of light as it is absorbed or emitted, and electrons move between energy levels.
by Giselle Littleton 1F
Thu Oct 03, 2019 4:51 pm
Forum: Significant Figures
Topic: Does molar mass count for sig figs?
Replies: 6
Views: 128

Re: Does molar mass count for sig figs?

It's your final answer to a problem that counts for sig figs. However, to ensure that your final answer is accurate, I would keep the molar mass and other calculations in between in their longest form as evident on the periodic table and then use sig figs for your final answer.
by Giselle Littleton 1F
Thu Oct 03, 2019 4:46 pm
Forum: Balancing Chemical Reactions
Topic: "Combustion" Term
Replies: 8
Views: 149

Re: "Combustion" Term

Combustion means burning a substance in the presence of oxygen. This is a chemical reaction that produces CO2 and H20.
by Giselle Littleton 1F
Thu Oct 03, 2019 4:44 pm
Forum: Properties of Light
Topic: Properties of light in class
Replies: 3
Views: 74

Re: Properties of light in class

Hertz is essentially the number of cycles or wavelengths per second. Wave frequency is expressed through these units. We can find frequency by dividing the velocity by the wavelength.
by Giselle Littleton 1F
Thu Oct 03, 2019 3:58 pm
Forum: Limiting Reactant Calculations
Topic: Percentage Yields
Replies: 8
Views: 108

Re: Percentage Yields

A percentage yield means how much you get in reality compared to what you thought you were going to get. In a perfect world and lab setting, the actual yield would be equal to the theoretical yield. However, due to somewhat unavoidable factors, the actual yield will always be less than the theoretic...
by Giselle Littleton 1F
Wed Oct 02, 2019 1:59 pm
Forum: Student Social/Study Group
Topic: Study Group Fall 2019
Replies: 32
Views: 1570

Re: Study Group Fall 2019

Also interested!
by Giselle Littleton 1F
Wed Oct 02, 2019 1:57 pm
Forum: Molarity, Solutions, Dilutions
Topic: Please clarify what M means
Replies: 5
Views: 78

Please clarify what M means

The beginning of a problem states that a solution is diluted with 1.00 L of 0.4M potassium chloride. Does 0.4M stand for 0.4 mols or O.4 mols/L (molarity)?

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