Search found 61 matches

by Jacqueline Duong 1H
Sun Mar 17, 2019 10:04 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: galvanic cells
Replies: 6
Views: 15

Re: galvanic cells

A porous disk is indicated by a single line, and a salt bridge is 2 lines
by Jacqueline Duong 1H
Sun Mar 17, 2019 9:58 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: adiabatic systems
Replies: 7
Views: 27

Re: adiabatic systems

Adiabatic is when q=0, so that would mean that there is no transfer of heat.
by Jacqueline Duong 1H
Sun Mar 17, 2019 9:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q
Replies: 6
Views: 25

Re: Q

When calculating Q, the concentrations do not have to be in standard conditions.
by Jacqueline Duong 1H
Sun Mar 17, 2019 9:33 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Endergonic vs. Endothermic
Replies: 6
Views: 49

Re: Endergonic vs. Endothermic

An endergonic reaction is where energy is absorbed, therefore making delta G positive. Exergonic is when energy is released, therefore delta G would be negative.
by Jacqueline Duong 1H
Sun Mar 17, 2019 8:48 am
Forum: Van't Hoff Equation
Topic: Van't Hoff use
Replies: 13
Views: 122

Re: Van't Hoff use

You would use Van't Hoff equation when there is a temperature change and K
by Jacqueline Duong 1H
Sun Mar 17, 2019 8:02 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Isothermal, Isobaric, Adiabatic
Replies: 2
Views: 11

Re: Isothermal, Isobaric, Adiabatic

I am not sure, but I think it's better to know just in case. Isothermal is where the temperature stays constant in a system. Isobaric is where the pressure is constant, and adiabatic is where transfers of matter and energy as heat are prohibited.
by Jacqueline Duong 1H
Sun Mar 17, 2019 7:57 am
Forum: Calculating Work of Expansion
Topic: S=0
Replies: 12
Views: 107

Re: S=0

S is equal to zero when there is no change in the state of entropy and temperature reaches 0 K
by Jacqueline Duong 1H
Sun Mar 17, 2019 7:52 am
Forum: General Rate Laws
Topic: Exergonic reaction
Replies: 3
Views: 13

Re: Exergonic reaction

A reaction is exergonic when it is releasing energy, which would result in a negative delta G since it is losing energy.
by Jacqueline Duong 1H
Sun Mar 17, 2019 7:49 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Exothermic vs. Endothermic
Replies: 5
Views: 29

Re: Exothermic vs. Endothermic

Every reaction has activation energy since it is the minimum amount of energy needed to be able to undergo the reaction. Activation energy is the difference in the energy between the transition state and the reactants.
by Jacqueline Duong 1H
Sun Mar 17, 2019 5:35 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ∆G and work
Replies: 3
Views: 21

Re: ∆G and work

Delta G is equal to the maximum amount of energy available to do work at constant temperature and pressure.
by Jacqueline Duong 1H
Sun Mar 17, 2019 5:26 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pressure Equation
Replies: 7
Views: 73

Re: Pressure Equation

You would use that equation when there is a change in pressure.
by Jacqueline Duong 1H
Sun Mar 17, 2019 4:53 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work done vs work on system
Replies: 18
Views: 127

Re: Work done vs work on system

When work is being done ON the system, work is positive. When work is being done BY the system, work is negative since it is losing energy.
by Jacqueline Duong 1H
Sun Mar 17, 2019 4:47 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic and isothermal
Replies: 6
Views: 49

Re: Adiabatic and isothermal

Adiabatic is an isolated system where transfers of matter and energy as heat are prohibited. Isothermal is a process where it is the temperature that stays constant.
by Jacqueline Duong 1H
Sun Mar 17, 2019 4:38 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Term Differences (Heat, Enthalpy, Temperature, and Work)
Replies: 4
Views: 39

Re: Term Differences (Heat, Enthalpy, Temperature, and Work)

Heat is the transfer of energy due to a difference in temperature. Enthalpy is the heat absorbed or released from a system under constant pressure, where it is affected by factors such as the state of the reactants and products. Temperature is a measure of heat, where temperature can be used to indi...
by Jacqueline Duong 1H
Sun Mar 17, 2019 3:50 am
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 7
Views: 45

Re: Activation Energy

Activation energy is the minimum amount of energy required for a certain reaction to occur. In an energy profile diagram, it would be the peak of the graph.
by Jacqueline Duong 1H
Sun Mar 17, 2019 3:42 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Equation
Replies: 8
Views: 29

Re: Equation

Yep, usually A=1 unless it was explicitly stated otherwise
by Jacqueline Duong 1H
Sun Mar 17, 2019 1:43 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 9
Views: 33

Re: Catalysts

A catalyst would lower the peak on a curve since it can speed up the rate of a chemical reaction by providing a faster route.
by Jacqueline Duong 1H
Sun Mar 17, 2019 1:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Effect of increased concentration on equilibrium
Replies: 9
Views: 66

Re: Effect of increased concentration on equilibrium

the system will favor the forward reaction and produce more products
by Jacqueline Duong 1H
Sun Mar 17, 2019 1:28 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: equilibirum expression
Replies: 3
Views: 16

Re: equilibirum expression

Pure liquids and solids do not appear in the expression
by Jacqueline Duong 1H
Sat Mar 16, 2019 11:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ignoring x
Replies: 16
Views: 123

Re: ignoring x

We can ignore x when the 5% rule applies to it, which is when x is less than 5% of the initial concentration.
by Jacqueline Duong 1H
Sat Mar 16, 2019 11:03 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Units
Replies: 6
Views: 52

Re: Units

There are no units since the units should cancel
by Jacqueline Duong 1H
Sat Mar 16, 2019 10:57 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature and Le Chatlier's Principle
Replies: 6
Views: 20

Re: Temperature and Le Chatlier's Principle

For an exothermic reaction, the formation of products is found to be favored by lowering the temperature. For an endothermic reaction, the products are favored by an increase in temperature. So basically, raising the temperature of a reaction mixture at equilibrium will shift the reaction in the end...
by Jacqueline Duong 1H
Sat Mar 16, 2019 9:13 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isometric/Isochoric
Replies: 10
Views: 55

Re: Isometric/Isochoric

Isochoric is where the volume stays constant, isobaric is where the pressure stays constant, and adiabatic is where transfers of matter and of energy as heat are prohibited (therefore q=0)
by Jacqueline Duong 1H
Sat Mar 16, 2019 9:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K and Kc
Replies: 6
Views: 27

K and Kc

What is the difference between K and Kc, and when do we know to use which one?
by Jacqueline Duong 1H
Sat Mar 16, 2019 8:05 pm
Forum: Ideal Gases
Topic: units
Replies: 15
Views: 97

Re: units

it's because there shouldn't be any units for K
by Jacqueline Duong 1H
Sat Mar 16, 2019 7:40 pm
Forum: Ideal Gases
Topic: Ideal gas constant R
Replies: 9
Views: 88

Re: Ideal gas constant R

Yeah, it depends on the question and what units you would need to be able to cancel out
by Jacqueline Duong 1H
Thu Mar 14, 2019 4:38 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: ICE
Replies: 19
Views: 186

Re: ICE

E is the equilibrium concentration
by Jacqueline Duong 1H
Thu Mar 14, 2019 4:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Calculating Equilibrium Composition
Replies: 2
Views: 16

Calculating Equilibrium Composition

When using the quadratic equation to calculate the equilibrium composition, how do we know which of the two values is the right one for x?
by Jacqueline Duong 1H
Thu Mar 14, 2019 4:32 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibruim Assessment
Replies: 5
Views: 45

Re: Equilibruim Assessment

to add on to the x being small, if it is less than 5% of the initial value, then x is negligible when adding or subtracting from a number
by Jacqueline Duong 1H
Sun Dec 09, 2018 9:23 pm
Forum: Sigma & Pi Bonds
Topic: Amount of sigma bonds
Replies: 6
Views: 111

Re: Amount of sigma bonds

There can only be one sigma bond since a single bond has 1 sigma bond.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:41 pm
Forum: Sigma & Pi Bonds
Topic: Double Bonds
Replies: 9
Views: 118

Re: Double Bonds

A double bond has 1 sigma bond and 1 pi bond.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:38 pm
Forum: Sigma & Pi Bonds
Topic: Triple bond?
Replies: 11
Views: 119

Re: Triple bond?

A triple bond means that there are 2 pi bonds and 1 sigma bond.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:37 pm
Forum: Sigma & Pi Bonds
Topic: Number of sigma and pi bonds
Replies: 5
Views: 93

Re: Number of sigma and pi bonds

To count the number of sigma and pi bonds there are, a single bond would be sigma, a double bound would be a pi bond and sigma bond and a triple bond would be one sigma bond and 2 pi bonds.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AX3E
Replies: 18
Views: 131

Re: AX3E

It would be trigonal pyramidal.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 5
Views: 62

Re: Polarity

To have a polar bond, it means that the electrons forming that bond are unequally distributed.
by Jacqueline Duong 1H
Sun Dec 09, 2018 8:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VESPR Shapes
Replies: 3
Views: 57

Re: VESPR Shapes

Thank you, that was actually really helpful!
by Jacqueline Duong 1H
Sun Dec 09, 2018 7:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-shaped structures
Replies: 3
Views: 49

Re: T-shaped structures

Yeah, the bond angle for a t-shape would be 90.
by Jacqueline Duong 1H
Sun Dec 09, 2018 7:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 2
Views: 31

Re: Polarity

Not necessarily, the lone pairs just means that there's more of a repulsion and the shape changes.
by Jacqueline Duong 1H
Sun Dec 09, 2018 7:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw
Replies: 13
Views: 167

Re: Seesaw

The angles for a seesaw shape are less than 90 and 120.
by Jacqueline Duong 1H
Sun Nov 18, 2018 4:08 pm
Forum: Hybridization
Topic: Sigma and Pi Bonds [ENDORSED]
Replies: 12
Views: 151

Sigma and Pi Bonds [ENDORSED]

Can someone please explain sigma and pi bonds and how they are formed?
by Jacqueline Duong 1H
Sun Nov 18, 2018 3:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: cis and trans dichloroethene
Replies: 3
Views: 33

cis and trans dichloroethene

Can someone please explain cis-dichloroethene and trans-dichloroethene and what the difference between the two is?
by Jacqueline Duong 1H
Sun Nov 18, 2018 3:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polyatomic Molecules
Replies: 1
Views: 27

Polyatomic Molecules

How can a polyatomic molecule be nonpolar if its bonds are polar?
by Jacqueline Duong 1H
Sat Nov 10, 2018 3:42 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Strengths of Repulsion
Replies: 2
Views: 24

Strengths of Repulsion

Why do lone pairs have a more strongly repelling effect then electrons in bonds?
by Jacqueline Duong 1H
Fri Nov 09, 2018 1:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula
Replies: 2
Views: 55

Re: VSEPR Formula

The VSEPR formula is AXnEm, where A represents a central atom, X represents an attached atom, and E represents a lone pair.
by Jacqueline Duong 1H
Fri Nov 09, 2018 1:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Naming the molecular shape
Replies: 4
Views: 68

Naming the molecular shape

When naming the molecular shape, do we also consider any lone pairs that are present? Or do we only take into consideration the positions of the atoms?
by Jacqueline Duong 1H
Sun Nov 04, 2018 4:04 pm
Forum: Resonance Structures
Topic: resonance structures for the test
Replies: 2
Views: 33

Re: resonance structures for the test

Yeah, I think we would have to draw all the resonance structures with a double headed arrow connecting them.
by Jacqueline Duong 1H
Sun Nov 04, 2018 4:00 pm
Forum: Electronegativity
Topic: Electron Affinity vs. Ionization Energy
Replies: 8
Views: 105

Re: Electron Affinity vs. Ionization Energy

Ionization energy increases across a period and decreases down a group, while electron affinity is also the same where it increase across a period and decreases down a group.
by Jacqueline Duong 1H
Sun Nov 04, 2018 3:33 pm
Forum: Lewis Structures
Topic: Drawing Lewis Structures
Replies: 4
Views: 71

Re: Drawing Lewis Structures

Yeah I think you would need to draw the resonance hybrid, where you draw the two resonance structures connected with a double headed arrow.
by Jacqueline Duong 1H
Sun Oct 28, 2018 5:19 pm
Forum: Ionic & Covalent Bonds
Topic: Hydrogen Bonds
Replies: 5
Views: 51

Re: Hydrogen Bonds

Hydrogen bonds are weaker because it involves the attraction between hydrogen and another molecule, whereas covalent and ionic bonds are a sharing or transfer of electrons which is stronger.
by Jacqueline Duong 1H
Sun Oct 28, 2018 4:43 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Bonds vs Covalent Bonds
Replies: 7
Views: 131

Re: Ionic Bonds vs Covalent Bonds

To add on, basically covalent bonds are stronger than ionic bonds in aqueous solutions, whereas ionic bonds are stronger in non-aqueous solutions.
by Jacqueline Duong 1H
Sun Oct 28, 2018 4:31 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 7
Views: 93

Re: Covalent Bonds

Nonmetals form anions because they gain electrons due to their high charge, which results in the formation of negatively charged ions.
by Jacqueline Duong 1H
Sun Oct 21, 2018 6:26 pm
Forum: DeBroglie Equation
Topic: Smallest Detectable Wavelength
Replies: 2
Views: 49

Re: Smallest Detectable Wavelength

I think he said it was 10^-18
by Jacqueline Duong 1H
Sun Oct 21, 2018 6:00 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Shape of Orbitals
Replies: 3
Views: 44

Shape of Orbitals

What are the different shapes of each orbital and an easy way to memorize the difference? Will we need to draw them on the test?
by Jacqueline Duong 1H
Sun Oct 21, 2018 4:08 pm
Forum: *Shrodinger Equation
Topic: Application of Schrodinger's Equation
Replies: 2
Views: 97

Re: Application of Schrodinger's Equation

If I remember correctly, Schrodinger's equation is a wave equation that precisely predicts the probability of behavior of a system.
by Jacqueline Duong 1H
Sun Oct 14, 2018 12:07 am
Forum: Einstein Equation
Topic: Numbers to memorize
Replies: 22
Views: 341

Re: Numbers to memorize

Yeah, before the test we're given an equation sheet that has those numbers. So luckily, we don't need to memorize them!
by Jacqueline Duong 1H
Sat Oct 13, 2018 11:49 pm
Forum: Properties of Light
Topic: Units for a Joule [ENDORSED]
Replies: 3
Views: 52

Re: Units for a Joule [ENDORSED]

This is because joule is a unit of work, and the equation for work is: work = force x displacement. When you expand this, you get work = mass x acceleration x displacement. The units for mass is kg, for acceleration is m/s^2, and for displacement is m. As a result, when you times them all together, ...
by Jacqueline Duong 1H
Sat Oct 13, 2018 11:26 pm
Forum: DeBroglie Equation
Topic: explain debroglie equation?
Replies: 3
Views: 51

Re: explain debroglie equation?

The De Broglie equation is λ = h/mv, where λ is the wavelength, h is Planck's constant (6.626 x 10^-34), m is the mass of the particle, and v is the velocity of the particle. You use this equation to find the wavelength of a moving particle.
by Jacqueline Duong 1H
Fri Oct 05, 2018 5:44 pm
Forum: Significant Figures
Topic: Determining Sig Figs
Replies: 6
Views: 65

Re: Determining Sig Figs

When you are multiplying or dividing, the number of sig figs in your answer is determined by the number with the least amount of sig figs. However, when you are adding or subtracting, the number of decimal places in the answer is determined by the smallest number of decimal places in the problem.
by Jacqueline Duong 1H
Fri Oct 05, 2018 5:00 pm
Forum: SI Units, Unit Conversions
Topic: HW E.9
Replies: 3
Views: 119

Re: HW E.9

Yeah, Lavelle said that he would give us the formula, and it won't be until later on when we learn how to write formulas that he will expect us to do it by ourselves.
by Jacqueline Duong 1H
Fri Oct 05, 2018 4:33 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical formula set up
Replies: 9
Views: 118

Re: Empirical formula set up

If I remember correctly, Lavelle said it was just easier to answer the problem since it makes it simpler and the numbers are easier to work with.

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