Search found 100 matches

by Joowon Seo 3A
Fri Mar 13, 2020 6:09 pm
Forum: Van't Hoff Equation
Topic: When to use
Replies: 5
Views: 102

Re: When to use

It relates the change in temperature to the change in reaction constant.
by Joowon Seo 3A
Fri Mar 13, 2020 6:08 pm
Forum: Calculating Work of Expansion
Topic: Positive or negative work
Replies: 15
Views: 227

Re: Positive or negative work

work is positive when it is done on the system. When the system does work, the work is negative.
by Joowon Seo 3A
Fri Mar 13, 2020 6:04 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Relationship between work, cell potential, and delta G
Replies: 6
Views: 117

Re: Relationship between work, cell potential, and delta G

When delta G is negative, there is energy free to do work. Cell potential wants to go down. IF cell potential goes down there is a release of energy free to do work.
by Joowon Seo 3A
Fri Mar 13, 2020 6:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reduction Potential
Replies: 4
Views: 31

Re: Reduction Potential

the anode is more negative and the cathode is more positive.
by Joowon Seo 3A
Fri Mar 13, 2020 6:02 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Identification
Replies: 4
Views: 84

Re: Identification

Generally all diatomic elements being themselves in their natural state like gaseous hydrogen or graphite for carbon.
by Joowon Seo 3A
Fri Mar 13, 2020 5:56 pm
Forum: Second Order Reactions
Topic: Termolecular
Replies: 15
Views: 413

Re: Termolecular

It is when three molecules collide in order to form a product.
by Joowon Seo 3A
Fri Mar 13, 2020 5:55 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Step Mechanism
Replies: 7
Views: 58

Re: Slow Step Mechanism

It entirely depends on the reaction itself.
by Joowon Seo 3A
Fri Mar 13, 2020 5:54 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Identifying First and Second Order
Replies: 3
Views: 31

Re: Identifying First and Second Order

If you plot ln of reactant with time and it is a straight line it is first order. If you plot 1/R vs time and it is a straight line it is second order.
by Joowon Seo 3A
Fri Mar 13, 2020 5:51 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Arrhenius Equation
Replies: 8
Views: 65

Re: Arrhenius Equation

The equation helps us relate temperature, reaction constant, and the activation energy. IF plotting lnk to 1/T the slope is -Ea/R
by Joowon Seo 3A
Tue Mar 03, 2020 9:04 am
Forum: Second Order Reactions
Topic: rate
Replies: 3
Views: 235

Re: rate

if we change a second order equations reactant by a factor, its rate will change by the factor^2
by Joowon Seo 3A
Tue Mar 03, 2020 9:03 am
Forum: General Rate Laws
Topic: Homework 7A.17
Replies: 2
Views: 58

Re: Homework 7A.17

you can look at the the factor of how much the rate and the reactant are changing then deduce which order the reactant is.
by Joowon Seo 3A
Tue Mar 03, 2020 9:01 am
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: lnQ vs logQ
Replies: 5
Views: 54

Re: lnQ vs logQ

It is ok to use either but remember that the those two are not the same thing.
by Joowon Seo 3A
Tue Mar 03, 2020 9:00 am
Forum: First Order Reactions
Topic: First order plot
Replies: 3
Views: 43

Re: First order plot

it is used to derive k as it is the negative slope of the equation.
by Joowon Seo 3A
Tue Mar 03, 2020 8:59 am
Forum: Zero Order Reactions
Topic: Difference
Replies: 5
Views: 77

Re: Difference

No matter how we change the concentration of the zero order reactant, the reaction rate will not change. For a first order equation, the rate will linearly change when we change the reactant. For a second order when we change the reactant, it will change by the square of the reactant change.
by Joowon Seo 3A
Tue Mar 03, 2020 8:55 am
Forum: General Rate Laws
Topic: class notes
Replies: 2
Views: 35

Re: class notes

A slow step is the series of reactions use to convert the initial reactants to the final products.
by Joowon Seo 3A
Thu Feb 27, 2020 9:44 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Eo as an intensive property
Replies: 9
Views: 106

Re: Eo as an intensive property

The property does not change no matter how much of it occurs. Therefore if we must balance a reaction we can't change
by Joowon Seo 3A
Thu Feb 27, 2020 9:43 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Work
Replies: 4
Views: 46

Re: Work

The potential difference is the maximum amount of Gibbs Free energy, the energy available to do work.
by Joowon Seo 3A
Thu Feb 27, 2020 9:39 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: delta g
Replies: 3
Views: 33

Re: delta g

Because there is no more free energy to do work when the reaction is at equilibrium because the reaction is at the most stable point.
by Joowon Seo 3A
Thu Feb 27, 2020 9:36 am
Forum: Balancing Redox Reactions
Topic: Cell Diagrams
Replies: 3
Views: 34

Re: Cell Diagrams

Since the left side is the anode, the thing on the left must be oxidized.
by Joowon Seo 3A
Mon Feb 17, 2020 10:06 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: G vs G knot
Replies: 15
Views: 106

Re: G vs G knot

is when the reaction is under standard conditions meaning that the temperature is at 25 C and the pressure is at 1 atm
Regular G is for any temperature and for any pressure
by Joowon Seo 3A
Mon Feb 17, 2020 10:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: sign of delta G
Replies: 9
Views: 120

Re: sign of delta G

When delta G is negative it becomes spontaneous and the reaction will favor the products if delta G is positive the reaction will favor the reactants
by Joowon Seo 3A
Mon Feb 17, 2020 10:02 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: importance of -RTlnk
Replies: 7
Views: 64

Re: importance of -RTlnk

K is the equilibrium constant where the equation will not change if K=Q then the standard change in gibbs free energy is zero. so we get the equation from to G=-RTlnK
by Joowon Seo 3A
Mon Feb 17, 2020 9:59 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Exothermic rxns being spontaneous
Replies: 5
Views: 65

Re: Exothermic rxns being spontaneous

Spontaneity means that the change in gibbs free energy is negative. Most exothermic reactions have a decrease in enthalpy meaning an increase in heat to the surroundings as well as an increase in entropy
by Joowon Seo 3A
Mon Feb 17, 2020 9:57 pm
Forum: Van't Hoff Equation
Topic: Entropy in Van't Hoff Equation
Replies: 3
Views: 37

Re: Entropy in Van't Hoff Equation

We are assuming that both the initial and final entropy will go up the same amount so that the difference in the entropy will stay the same.
by Joowon Seo 3A
Mon Feb 10, 2020 11:46 pm
Forum: Calculating Work of Expansion
Topic: Reversible Reactions
Replies: 2
Views: 25

Re: Reversible Reactions

Since it uses all of the heat going into the system and converts it to work. The heat is not converted to the temperature of a system.
by Joowon Seo 3A
Mon Feb 10, 2020 11:45 pm
Forum: Calculating Work of Expansion
Topic: calculating work of a reversible reaction
Replies: 5
Views: 61

Re: calculating work of a reversible reaction

work of a system will always be negative because we use the pressure external to calculate the work. The system will lose energy since it is doing work
by Joowon Seo 3A
Mon Feb 10, 2020 11:42 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: equation conversions
Replies: 1
Views: 20

Re: equation conversions

We start out with the equation

we will then have the equation

since for an isothermal reaction we have

Then we can sub in that for entropy and we will have the equation
by Joowon Seo 3A
Mon Feb 10, 2020 11:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: q vs delta H
Replies: 2
Views: 25

Re: q vs delta H

They are satisfied under conditions of standard pressure.
by Joowon Seo 3A
Mon Feb 10, 2020 11:34 pm
Forum: Phase Changes & Related Calculations
Topic: Work (w)
Replies: 8
Views: 65

Re: Work (w)

Work is not a state property because it depends on the path taken. If you walk a really roundabout path and a path straight from point a to point b you will spend a different amount of energy and do a different amount of work.
by Joowon Seo 3A
Sun Feb 02, 2020 10:32 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Negative Enthalpy
Replies: 3
Views: 27

Re: Negative Enthalpy

They do not necessarily happen by themselves since enthalpy is a state function. It depends on the intermediate energy when going from the initial enthalpy to the final enthalpy.
by Joowon Seo 3A
Sun Feb 02, 2020 10:30 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work and Heat
Replies: 2
Views: 14

Re: Work and Heat

work and heat depend on how the path was taken from the initial value to final value.
by Joowon Seo 3A
Sun Feb 02, 2020 10:29 pm
Forum: Calculating Work of Expansion
Topic: Force
Replies: 3
Views: 39

Re: Force

force is pressure times area since pressure is the amount of force in a given area.
by Joowon Seo 3A
Sun Feb 02, 2020 10:27 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Adiabatic Wall
Replies: 3
Views: 30

Re: Adiabatic Wall

Adiabatic means that energy cannot be absorbed or ejected as heat so the system must do work or work must be done on a system in order to absorb or release energy.
by Joowon Seo 3A
Sun Feb 02, 2020 10:23 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Steam burns
Replies: 8
Views: 67

Re: Steam burns

Because of the energy to convert boiling water to steam is a lot. So when steam condenses on your skin, all the energy expelled to form the bonds between water will get sent to your skin causing extreme burns.
by Joowon Seo 3A
Sun Jan 26, 2020 10:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Water Phase Change
Replies: 6
Views: 55

Re: Water Phase Change

There needs to be energy required to break the hydrogen bonds in between the water molecules.
by Joowon Seo 3A
Sun Jan 26, 2020 10:28 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 7
Views: 72

Re: Phase Changes

To accommodate for the phase change of the material, add the reaction enthalpy of the phase change onto the reaction.
by Joowon Seo 3A
Sun Jan 26, 2020 10:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 3 methods
Replies: 5
Views: 42

Re: 3 methods

It would depend on the information the question gives you. It also depends on what you are looking for. If you are looking for an accurate enthalpy, you should avoid using bond enthalpies because it is the least accurate.
by Joowon Seo 3A
Sun Jan 26, 2020 10:25 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 9
Views: 70

Re: Hess's Law

Hess's law states that enthalpies can be additive. You can add the total reaction enthalpies.
by Joowon Seo 3A
Sun Jan 26, 2020 10:19 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy
Replies: 3
Views: 29

Re: Enthalpy

Enthalpy is a state because it does matter how it gets to the final value.
by Joowon Seo 3A
Mon Jan 20, 2020 6:24 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: definition of a buffer
Replies: 8
Views: 80

Re: definition of a buffer

A buffer has a weak acid/base with its conjugate. The conjugate can take/give a proton in solution, so it can resist a change in pH.
by Joowon Seo 3A
Mon Jan 20, 2020 6:23 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Endothermic vs Exothermic
Replies: 7
Views: 73

Re: Endothermic vs Exothermic

A reaction is generally endothermic if involves the breaking of bonds which causes the absorption of heat. A reaction is generally exothermic when the product forms bonds.
by Joowon Seo 3A
Mon Jan 20, 2020 6:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: q vs k
Replies: 9
Views: 48

Re: q vs k

The q value will eventually reach k given a long period of time, because that's where the reaction occurs at equilibrium.
by Joowon Seo 3A
Mon Jan 20, 2020 6:19 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Difference in PH between strong and weak acids
Replies: 11
Views: 92

Re: Difference in PH between strong and weak acids

A weak acid does not give up it's protons as easily as a strong acid. Therefore, there is a less concentration of hydronium ions and therefore a lower pH
by Joowon Seo 3A
Mon Jan 20, 2020 6:18 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic Reactions
Replies: 4
Views: 31

Re: Endothermic Reactions

In an endothermic reaction, heat can be used to break bonds. Therefore, if you increase the heat (which could be noted as a reactant) by Le Chatelier's principle, the formation of products increases.
by Joowon Seo 3A
Tue Jan 14, 2020 9:14 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changes in pressure
Replies: 4
Views: 47

Re: Changes in pressure

If we change the volume so that the pressure increases, the concentration of the products and reactants changes, so more reactions happen to keep it at the equilibrium constant.
by Joowon Seo 3A
Tue Jan 14, 2020 9:12 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 5
Views: 64

Re: Le Chatelier's Principle

It applies if the physical parameters are produced. For example, if a reaction produces heat, more reactions will be favored to form reactants if we add heat.
by Joowon Seo 3A
Tue Jan 14, 2020 9:11 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: equilibrium constants and inputs
Replies: 4
Views: 50

Re: equilibrium constants and inputs

Solids cannot have a concentration. Liquids are not included in the equation since their concentration essentially does not change so we leave it out.
by Joowon Seo 3A
Tue Jan 14, 2020 9:09 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Weak Bases and Acids
Replies: 2
Views: 15

Re: Weak Bases and Acids

All weak acids or bases have ka or kb values. Strong acids are when the compounds totally dissociate, so they would have to have remarkably high k values in order to be called strong acids or bases.
by Joowon Seo 3A
Tue Jan 14, 2020 9:08 am
Forum: Ideal Gases
Topic: Partial Pressure
Replies: 8
Views: 84

Re: Partial Pressure

It is called partial pressure because in a mixture of gases, each individual gas contributes to the overall pressure.
by Joowon Seo 3A
Sat Dec 07, 2019 4:44 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Weak Acids
Replies: 4
Views: 53

Re: Weak Acids

Weak acids generally don't give off their H+ ions as easily as strong acids. It will generally give you the pKa value of an acid since every proton of a weak acid doesn't dissociate.
by Joowon Seo 3A
Sat Dec 07, 2019 4:42 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand polydentate
Replies: 4
Views: 120

Re: Ligand polydentate

It depends on how many lone pairs the ligand has. For example, en has two nitrogen with lone pairs and is a bidentate.
by Joowon Seo 3A
Sat Dec 07, 2019 4:39 pm
Forum: Naming
Topic: Biological Functions
Replies: 2
Views: 62

Re: Biological Functions

Myoglobin contains a naturally occurring coordination compound where the central TM cation is Fe. The Fe binds to oxygen in order to transport it around the body.
by Joowon Seo 3A
Sat Dec 07, 2019 4:36 pm
Forum: Polyprotic Acids & Bases
Topic: polyprotic acids and bases
Replies: 2
Views: 81

Re: polyprotic acids and bases

It is polyprotic if it can recieve or give more than one H+
by Joowon Seo 3A
Sat Dec 07, 2019 4:30 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Periodic Trends
Replies: 8
Views: 188

Re: Periodic Trends

polarizability depends on size of an atom, because the electron cloud can distort more easily. polarizing power: the smaller the cation, the more powerful it is.
by Joowon Seo 3A
Sat Dec 07, 2019 4:29 pm
Forum: Naming
Topic: transition metal suffix
Replies: 2
Views: 36

Re: transition metal suffix

Only if the complex is negatively will the metal end with -ate. Furthermore some metals have special names. For iron for example, you would say ferrate instead of ironate.
by Joowon Seo 3A
Sat Dec 07, 2019 12:47 pm
Forum: Polyprotic Acids & Bases
Topic: polyprotic acids
Replies: 3
Views: 102

Re: polyprotic acids

Because it is easier for the first hydrogen to be dissociated from the acid. The atom holds on to the second and the third protons more tightly than the first.
by Joowon Seo 3A
Sat Dec 07, 2019 12:46 pm
Forum: Photoelectric Effect
Topic: Module Question
Replies: 1
Views: 119

Re: Module Question

So to remove electrons from 1 mol of sodium it is 150.6 KJ.mol^-1. So to find the energy needed for one sodium atom, you just need to divide the number by the number of atoms in a mol.
by Joowon Seo 3A
Sat Dec 07, 2019 12:43 pm
Forum: Identifying Acidic & Basic Salts
Topic: J.17
Replies: 2
Views: 42

Re: J.17

Lavelle has stated in class that the 1st and 2nd group metals do not affect pH so they do not have to be written down in the proton transfer.
by Joowon Seo 3A
Sat Dec 07, 2019 12:40 pm
Forum: Calculating the pH of Salt Solutions
Topic: [OH-] & pOH
Replies: 2
Views: 85

Re: [OH-] & pOH

The p in p[OH-] stands for -log base 10. You can look at a graph of y=p(x). When the inputted value increases, the function decreases. Likewise the value of When the concentration of OH- decreases, the function p[OH-] increases. This is true for [H+] as well. https://dr282zn36sxxg.cloudfront.net/dat...
by Joowon Seo 3A
Sat Nov 30, 2019 1:14 pm
Forum: Bond Lengths & Energies
Topic: Melting Points
Replies: 8
Views: 209

Re: Melting Points

The things that affect intermolecular bonds are the types of bonds i.e. hydrogen and dipole-dipole bonds and the polarizability of the molecule where higher polarizability will mean greater bond strength.
by Joowon Seo 3A
Sat Nov 30, 2019 1:11 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 12
Views: 252

Re: Electronegativity

The higher the electronegativity, the shorter the bond, the harder it is to break the bond.
by Joowon Seo 3A
Sat Nov 30, 2019 1:09 pm
Forum: Air Pollution & Acid Rain
Topic: Clean Coal vs Dirty Coal?
Replies: 16
Views: 196

Re: Clean Coal vs Dirty Coal?

Dirty coal has more sulfur in it. So when it burns it releases more SO2 than clean coal
by Joowon Seo 3A
Sat Nov 30, 2019 1:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate and shape
Replies: 3
Views: 36

Re: polydentate and shape

Polydentate shapes are like rings since they have multiple bonding sites.
by Joowon Seo 3A
Sat Nov 30, 2019 1:07 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligands
Replies: 6
Views: 59

Re: Ligands

Since ligands donate an electron pair, they are considered lewis bases.
by Joowon Seo 3A
Sat Nov 23, 2019 6:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: [Fe(CN)6]4-
Replies: 5
Views: 56

Re: [Fe(CN)6]4-

CN binds to the Fe ion. The Fe ion is the central TM. By definition CN is a ligand. The charge is -4 because the Fe ion is +2. Since there are 6 CN- it becomes:
+2-6=-4
by Joowon Seo 3A
Sat Nov 23, 2019 6:01 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: How to tell?
Replies: 11
Views: 366

Re: How to tell?

Acids typically donate a proton. For example, with HCl aqueous it beomes H+ and Cl-.
by Joowon Seo 3A
Sat Nov 23, 2019 5:57 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Denticity
Replies: 2
Views: 46

Re: Denticity

Basically it refers to how many bonding sites the ligand has, like the ligand that forms the ring structure for example.
by Joowon Seo 3A
Sat Nov 23, 2019 5:54 pm
Forum: Biological Examples
Topic: Myoglobin
Replies: 3
Views: 42

Re: Myoglobin

Many transition metals like to form octahedrals. The iron in the complex is bonded to 5 nitrogens and in this case the O2 binds with the iron ion in the complex.
by Joowon Seo 3A
Sat Nov 23, 2019 5:49 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 2
Views: 31

Re: Cisplatin

If you look at the cisplatin there are two Cl- ions on the same side. These Cl- ions fall out and cisplatin binds to the nitrogen in two diferent guanine base pairs. This essentially stops the enzyme from taking apart the DNA, so the cell cannot divide.
by Joowon Seo 3A
Sun Nov 17, 2019 12:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Angles less than 109.5 degrees
Replies: 5
Views: 77

Re: Angles less than 109.5 degrees

It is because of the arrangement of electron densities. Since in a trigonal planar arrangement there are three regions of electron density therefore the angle has to be <120, but in a tetrahedral arrangement there are four regions of electron density therefore the angle has to be <109.5.
by Joowon Seo 3A
Sun Nov 17, 2019 12:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar Molecules
Replies: 4
Views: 50

Re: Polar Molecules

I am not sure what you mean but if dipoles are on the same side (or adjacent to each other) will not mean that they will not cancel out. For example BF3 where the shape is a trigonal planar. There are two fluorides on the bottom side of the molecule and one fluoride on the top, yet it is non-polar.
by Joowon Seo 3A
Sun Nov 17, 2019 11:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Van Der Waals Interaction
Replies: 11
Views: 101

Re: Van Der Waals Interaction

Since every molecule has electrons, every molecule will experience these forces. A van der waal force or induced dipole - induced dipole will be created because some discrepancy in electron density will create induced dipoles.
by Joowon Seo 3A
Sun Nov 17, 2019 11:40 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Model
Replies: 5
Views: 38

Re: VSEPR Model

Arrangement is the arrangement of electrons around the central atom. Shape is how those electrons repel each other and form the shape of the molecule.
by Joowon Seo 3A
Sun Nov 17, 2019 11:39 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs angular
Replies: 1
Views: 43

Re: Bent vs angular

Bent and angular are pretty much the same thing. You must look out however that bent or angular can have different bond angles. An arrangement of a tetrahedral and a shape of bent (>109.5) is different from an arrangement of a trigonal planar and the shape of bent (>120).
by Joowon Seo 3A
Sun Nov 10, 2019 1:01 pm
Forum: Bond Lengths & Energies
Topic: Shape of Molecules and bond strength
Replies: 5
Views: 50

Re: Shape of Molecules and bond strength

The shape affects it since a longer molecule has more surface area to interact with the other molecule than say a spherical molecule resulting in a stronger bond.
by Joowon Seo 3A
Sun Nov 10, 2019 12:59 pm
Forum: Bond Lengths & Energies
Topic: polarizability
Replies: 9
Views: 74

Re: polarizability

The size of the molecule generally affects polarizability. When polarizability of molecules increase the energy of bonds between molecules increase resulting in higher melting and boiling points.
by Joowon Seo 3A
Sun Nov 10, 2019 12:53 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: 3F. 15
Replies: 2
Views: 27

Re: 3F. 15

AsF5 has more electrons. Therefore has more polarizability, which means a higher boiling point.
by Joowon Seo 3A
Sun Nov 10, 2019 12:51 pm
Forum: Dipole Moments
Topic: Boiling Point
Replies: 11
Views: 129

Re: Boiling Point

Boiling point increases as a result of a higher intermolecular bond. For example water, which has hydrogen bonding, has stronger bonds than ethanol, which is nonpolar. This is shown by water's higher boiling point.
by Joowon Seo 3A
Sun Nov 10, 2019 12:48 pm
Forum: Bond Lengths & Energies
Topic: Strength of Interactions
Replies: 3
Views: 44

Re: Strength of Interactions

It is dependent on the polarizability of the two molecules (whether it has more e-). The distance of the bonds also matters, but it is mainly dependent on polarizability.
by Joowon Seo 3A
Sat Nov 02, 2019 1:09 pm
Forum: Electronegativity
Topic: Electronegativity on Test
Replies: 7
Views: 82

Re: Electronegativity on Test

I think you need to know the trend of electronegativity where it is opposite to the size of an atom (where it increases across a period and up a group)
by Joowon Seo 3A
Sat Nov 02, 2019 1:07 pm
Forum: Octet Exceptions
Topic: Octet Exception
Replies: 5
Views: 70

Re: Octet Exception

B and Al are also exceptions to this rule, as they must get 5 e- to get to an octet. However, since that is too many electrons they usually get 3 more e-
by Joowon Seo 3A
Sat Nov 02, 2019 1:06 pm
Forum: Octet Exceptions
Topic: 2C5a Help
Replies: 2
Views: 45

Re: 2C5a Help

I think is because of formal charges, Cl and O are double bonded which means that for Cl to have a formal charge of zero, the leftover radical e- must bind to Cl
by Joowon Seo 3A
Sat Nov 02, 2019 1:02 pm
Forum: Lewis Structures
Topic: central atom
Replies: 16
Views: 257

Re: central atom

Usually if its the only atom: e.g. CH4, then C, the unique atom, would go into the center. But in general, it is the one with the least electronegativity.
by Joowon Seo 3A
Sat Nov 02, 2019 1:00 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent character in ionic bonds
Replies: 3
Views: 58

Re: Covalent character in ionic bonds

Yes, because the cation is able to pull the shared electron more towards itself. This is used to explain why some salts cannot dissolve as easily in water than other salts.
by Joowon Seo 3A
Sun Oct 27, 2019 11:49 am
Forum: Ionic & Covalent Bonds
Topic: P, Cl, and S octet tule exceptions
Replies: 4
Views: 47

Re: P, Cl, and S octet tule exceptions

Their n=3 therefore they have access to the d-block (l=2) allowing them to place electrons into the d-block.
by Joowon Seo 3A
Sun Oct 27, 2019 11:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Assigning Orbitals to Elements
Replies: 4
Views: 67

Re: Assigning Orbitals to Elements

You just have to know that an electron must be in each orbital before there are any paired electrons.
by Joowon Seo 3A
Sun Oct 27, 2019 11:45 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ionization Energy
Replies: 4
Views: 42

Re: Ionization Energy

It is harder to remove the second electron since the positive charge on the nucleus has a greater force on the electrons since there are less electrons. This is also why cations get smaller.
by Joowon Seo 3A
Sun Oct 27, 2019 11:42 am
Forum: Trends in The Periodic Table
Topic: atomic Radii
Replies: 11
Views: 112

Re: atomic Radii

You have to take into the account the charge of the nucleus as well. For example, Fluorine has more electrons than oxygen, but it has a smaller radius than oxygen. That is why the size becomes smaller if you go down a group. However, just adding electrons to an atom will make it bigger. A fluorine i...
by Joowon Seo 3A
Sun Oct 27, 2019 11:39 am
Forum: Trends in The Periodic Table
Topic: Question on 1F.5 b
Replies: 3
Views: 46

Re: Question on 1F.5 b

A good way to remember is that the farther away an electron is, the easier it is to remove. Since Na has a greater size than Mg, it is easier to remove an electron; therefore, Na has a lower ionization energy.
by Joowon Seo 3A
Sat Oct 19, 2019 2:16 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question about last lecture
Replies: 4
Views: 43

Re: Question about last lecture

Both are correct, but the other one is more specific since it showed each electron in each subshell. The problem in the first one is that one could misunderstand and put 2 electrons in one subshell before filling all of the other ones first.
by Joowon Seo 3A
Sat Oct 19, 2019 2:14 pm
Forum: Quantum Numbers and The H-Atom
Topic: spin state (ms) quantum number
Replies: 2
Views: 55

Re: spin state (ms) quantum number

There is a way to prove that an atom's electron can spin up or spin down through the beaming of silver atoms shown in one of Lavelle's lectures. The electrons spin dictated where the atom would go. However,I think you just need to know that paired electrons have the opposite spin.
by Joowon Seo 3A
Sat Oct 19, 2019 2:11 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Hund's rule
Replies: 5
Views: 53

Re: Hund's rule

It is energetically favorable for electrons to have that configuration
by Joowon Seo 3A
Sat Oct 19, 2019 2:09 pm
Forum: Photoelectric Effect
Topic: One photon one atom interaction
Replies: 14
Views: 184

One photon one atom interaction

So after the energy of light surpasses the minimum energy needed to eject an electron, would increasing the energy of light (the frequency) increase the amount of electrons ejected at that point or would the amount of electrons ejected stay the same?
by Joowon Seo 3A
Sat Oct 19, 2019 2:07 pm
Forum: Photoelectric Effect
Topic: Problem 1B.15
Replies: 1
Views: 51

Re: Problem 1B.15

a) Use the DeBroglie equation for this problem since it both relates wavelength and the velocity of an electron. b)Use the photoelectric equation that relates to the frequency and energy in this case it would be E=h\nu + Kinetic energy but since there is no kinetic energy of an electron the kinetic ...
by Joowon Seo 3A
Sun Oct 06, 2019 11:22 am
Forum: Empirical & Molecular Formulas
Topic: What decimal place to round to when taking masses from the Periodic Table?
Replies: 19
Views: 339

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

Atomic numbers are usually carried out to four significant figures such as with hydrogen being 1.008 and carbon being 12.01. So I would just use four significant figures, and it should be fine.
by Joowon Seo 3A
Sun Oct 06, 2019 11:19 am
Forum: Empirical & Molecular Formulas
Topic: Empirical to Molecular Formulas
Replies: 2
Views: 88

Re: Empirical to Molecular Formulas

You would need the molar mass of the molecule you are trying to find. Then you would divide that molar mass by the molar mass of the empirical formula and get a number. If the number is like 2.9 or 5.1, you can round it to a whole number. If it is not a whole number, I suggest checking your work bec...
by Joowon Seo 3A
Sun Oct 06, 2019 11:08 am
Forum: Empirical & Molecular Formulas
Topic: Polyatomic Ions/Naming Compounds
Replies: 6
Views: 259

Re: Polyatomic Ions/Naming Compounds

I recommend putting them into groups and recognizing the patterns in the prefixes and the charges. Hypochlorite, Chlorite, Chlorate, and Perchlorate all have charges of -1. Polyatomic ions that start with hypo- and end with -ite have one oxygen atom. Polyatomic ions that just end in -ite have 2 oxyg...
by Joowon Seo 3A
Sun Oct 06, 2019 11:02 am
Forum: Balancing Chemical Reactions
Topic: Advice for Test 1
Replies: 7
Views: 118

Re: Advice for Test 1

In the syllabus, it says that he uses problems from the homework. I suggest if you want to practice more for the test is to do those problems listed in the syllabus.
by Joowon Seo 3A
Mon Sep 30, 2019 10:04 pm
Forum: Limiting Reactant Calculations
Topic: 2 Limiting Reactants
Replies: 9
Views: 101

Re: 2 Limiting Reactants

A little unrelated, but if there is a reaction that requires a catalyst, and the catalyst is present in very small quantities relative to the reactants, is it called a limiting reactant because it severely slows the reaction, or do we classify it as something else? The catalyst is not a limiting re...

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