## Search found 109 matches

Sat Mar 14, 2020 6:20 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: how to find k
Replies: 4
Views: 33

### Re: how to find k

You find the k value by using the Nernst equation and plugging in numbers for all the other values in the equation. From there you can use algebraic manipulation to find the value of k.
Sat Mar 14, 2020 6:19 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: electromotive force
Replies: 2
Views: 27

### Re: electromotive force

The electromotive force is the same as the cell potential of the cell.
Sat Mar 14, 2020 6:17 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 6
Views: 117

### Re: Nernst Equation

You don't need to convert but Dr. Lavelle said in lecture that the conversion can be useful in biological situations since it makes it easier to calculate pH.
Sat Mar 14, 2020 6:16 pm
Forum: Second Order Reactions
Topic: Termolecular
Replies: 15
Views: 433

### Re: Termolecular

Termolecular means that the reaction used three reactants to form the product.
Sat Mar 14, 2020 6:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: intermediate v. catalyst
Replies: 6
Views: 49

### Re: intermediate v. catalyst

The catalyst in the reaction will not be used up in the reaction. Therefore, it will be in the final overall reaction equation. Whereas an intermediate will be used up and won't show up in the overall reaction equation.
Sat Mar 14, 2020 6:12 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Order of Reactions
Replies: 4
Views: 59

### Re: Order of Reactions

The orders of each reactant will add up to the overall reaction order.
Sun Mar 08, 2020 9:05 pm
Forum: Zero Order Reactions
Topic: Zero Order Rxn
Replies: 7
Views: 319

### Re: Zero Order Rxn

Yes zero order is only dependent on the rate constant because it doesn't incorporate other factors like first-order and second-order reactions do.
Sun Mar 08, 2020 9:03 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow step vs. fast step
Replies: 3
Views: 39

### Re: Slow step vs. fast step

I think it will usually tell you which one is the slow step and the fast step when calculating. Another way to find out is by looking at the rate law and if there is a particular reactant in that law that is the same in one of the reactants of the steps then you can find out which is the slow step. ...
Sun Mar 08, 2020 9:01 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Exothermic vs. Endothermic
Replies: 14
Views: 120

### Re: Exothermic vs. Endothermic

You can tell it is exothermic when the activation energy is higher for reactants than it is for products. If the activation energy for products is higher than for reactants then the reaction is endothermic.
Sun Mar 08, 2020 9:00 pm
Forum: Second Order Reactions
Topic: Termolecular
Replies: 15
Views: 433

### Re: Termolecular

Termolecular means that there are three molecules that must come together for a reaction to occur. This means you would have three reactants.
Sun Mar 08, 2020 8:59 pm
Forum: First Order Reactions
Topic: Half Life
Replies: 8
Views: 65

### Re: Half Life

This is because in a second-order reaction the initial concentrations don't cancel out like they do in a first-order reaction. Because of this it doesn't matter for a first-order reaction but does for a second-order reaction.
Sun Mar 08, 2020 8:58 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Molecularity
Replies: 12
Views: 121

### Re: Molecularity

Molecularity is the number of molecules that will come together to react. If there is one it is unimolecular, two is bimolecular, and three is termolecular.
Wed Mar 04, 2020 7:20 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Strongest Reducing Agent
Replies: 5
Views: 80

### Re: Strongest Reducing Agent

The strongest reducing agent will be the reactant that is oxidized. When comparing oxidized reactants the strongest reducing agent will be the one with the lowest reduction potential.
Wed Mar 04, 2020 7:19 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: equation for Q
Replies: 3
Views: 48

### Re: equation for Q

It will always be the anode over the cathode since the equation for Q is products over reactants. The products of the equation will be the anode concentration and the cathode concentration will be the reactants.
Wed Mar 04, 2020 7:17 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation derivation
Replies: 3
Views: 49

### Re: Nernst Equation derivation

The Nernst equation can be derived using the equation for gibbs free energy. This equation is ∆G = ∆G˚ + RTlnQ. You can then set ∆G equal to -nFEcell and ∆G˚ to -nFE˚cell. Then you can divide both sides by -nF.
Wed Mar 04, 2020 7:14 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration Cell
Replies: 7
Views: 78

### Re: Concentration Cell

A concentration cell occurs when the anode and the cathode both have the same electrodes but with different concentrations. This would mean that the voltage difference would be created by the different concentrations rather than different cathodes.
Wed Mar 04, 2020 7:13 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Using partial pressure in Q
Replies: 6
Views: 76

### Re: Using partial pressure in Q

Yes you can use partial pressures and molar concentrations in Q. This is because partial pressures can be used to calculate the Q value as well as the molar concentrations of the reactants and products.
Sat Feb 29, 2020 8:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram order
Replies: 4
Views: 55

### Re: Cell diagram order

I don't think the order of those are particularly important but it is important to remember that the aqueous solution is always closest to the salt bridge and solids are always on the outside.
Sat Feb 29, 2020 8:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6L.5b
Replies: 2
Views: 40

### Re: 6L.5b

I think it means that the Pt is needed because there is no solid that can be either oxidized or reduced. Because of this Pt would need to be added to that side of the reaction.
Sat Feb 29, 2020 8:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Replies: 3
Views: 42

### Re: Adding an inert electrode

You add Pt when there is no solids involved in the galvanic cell for either the reduction or oxidation reactions.
Sat Feb 29, 2020 8:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode vs Cathode
Replies: 5
Views: 39

### Re: Anode vs Cathode

It is true that the cathode will be the Ecell that is more positive. You can also to see which part of the reaction is oxidized and which part is reduced to figure out what will be the anode or cathode in the half reactions.
Sat Feb 29, 2020 8:32 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E potentials
Replies: 5
Views: 62

### Re: E potentials

I think the reduction potentials will always be given for calculating Ecell. However, I do think that it is possible for them to give the E of oxidation and then you would have to do Ecell = Ecathode + Eanode.
Sun Feb 23, 2020 1:49 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 4
Views: 44

### Re: Anode and Cathode

In the notation the anode will be on the left side of the cell diagram and the cathode would be on the right side of the cell diagram.
Sun Feb 23, 2020 1:47 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: E° as state function?
Replies: 3
Views: 77

### Re: E° as state function?

E is not a state function and because of this we can't apply the same rules as we did for enthalpy and gibbs free energy. It is an intensive property so the value would stay the same no matter how many times the reaction occurs.
Sun Feb 23, 2020 1:46 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: ∆G=-nFE
Replies: 3
Views: 64

### Re: ∆G=-nFE

If it is at equilibrium you will have the naught symbol on the delta G and the E. If there is no not naught symbol, you can assume that the system is not at equilibrium.
Sun Feb 23, 2020 1:45 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Replies: 4
Views: 60

Since E is not a state function you can't apply the same concepts that we used in Hess's Law. E is an intensive property too so no matter how many times the reaction occurs the E will not change.
Sun Feb 23, 2020 1:41 pm
Forum: Balancing Redox Reactions
Topic: Cell Diagrams
Replies: 5
Views: 83

### Re: Cell Diagrams

Platinum is used in the problem because there is no conducting solid so platinum is used. Since it is resistant to oxidation it won't react easily in a redox reaction.
Sat Feb 15, 2020 10:26 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Replies: 3
Views: 53

The delta S for an irreversible expansion means that the surroundings change in entropy is 0. In an adiabatic system the total heat would be 0. This doesn't necessarily mean the same for irreversible expansion.
Sat Feb 15, 2020 10:24 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium
Replies: 5
Views: 62

### Re: Equilibrium

At equilibrium the delta G is 0 but delta H and delta S could still be nonzero numbers.
Sat Feb 15, 2020 10:22 am
Forum: Van't Hoff Equation
Topic: Van't Hoff
Replies: 6
Views: 80

### Re: Van't Hoff

You use this equation when you want to see the change in gibbs free energy relative to when the K value changes in the equation (products and reactants ratio).
Sat Feb 15, 2020 10:20 am
Forum: Balancing Redox Reactions
Topic: Redox reaction
Replies: 5
Views: 74

### Re: Redox reaction

I think you can look at the elements within a compound where you know the oxidation numbers and based on the total net charge of the molecule you can figure out the number for those elements you don't know.
Sat Feb 15, 2020 10:19 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta G
Replies: 6
Views: 60

### Re: Delta G

The naught sign means that the conditions are under STP or standard temperature and pressure. If the delta G has the naught symbol then so does the delta S and H.
Tue Feb 04, 2020 12:13 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Affect of temperature on entropy?
Replies: 5
Views: 69

### Re: Affect of temperature on entropy?

Increasing the temperature would increase the entropy because if you are increasing the temperature, there would be more states in the system. More states in a system means there is more entropy for the system.
Tue Feb 04, 2020 12:12 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: negative entropy
Replies: 4
Views: 29

### Re: negative entropy

Negative entropy is possible and just means that there is an overall decrease in entropy for the given system.
Tue Feb 04, 2020 12:11 pm
Forum: Calculating Work of Expansion
Topic: internal energy
Replies: 4
Views: 39

### Re: internal energy

Since U is the internal energy it is a state property because it does not matter the final or initial conditions/the path the system took to get to these results.
Tue Feb 04, 2020 12:09 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed system
Replies: 7
Views: 76

### Re: closed system

It would be a closed system because matter can't be exchanged with the surroundings since it is sealed but heat could be.
Tue Feb 04, 2020 12:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: defintion
Replies: 6
Views: 74

### Re: defintion

The internal energy or ∆U is the energy found in the system or the total energy of a closed system. This can be found using the equation ∆U = q + w where q is heat and w is the amount of work.
Mon Jan 27, 2020 10:04 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: delta U
Replies: 4
Views: 41

### Re: delta U

∆U is the change in the internal energy of the system. Mathematically it equals work + q.
Mon Jan 27, 2020 10:01 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeter
Replies: 7
Views: 83

### Re: Calorimeter

A calorimeter is a device that is used to measure the specific heat of a reaction.
Mon Jan 27, 2020 10:00 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: q vs. delta H
Replies: 6
Views: 109

### Re: q vs. delta H

The difference between q and ∆H is that q is the amount of energy transferred in or out of the system and ∆H is the total change in enthalpy of the system.
Mon Jan 27, 2020 9:58 pm
Forum: Phase Changes & Related Calculations
Topic: State functions
Replies: 5
Views: 47

### Re: State functions

Enthalpy is a state function since it depends on both the final and initial conditions of the system. Heat would not be a state function because heat is a measurement of change in energy and does not depend on the final and initial conditions of the system.
Mon Jan 27, 2020 9:56 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy and Heat
Replies: 6
Views: 65

### Re: Enthalpy and Heat

Heat is a transfer of energy due to a specific temperature whereas enthalpy is the change in the amount of heat in a system at constant pressure.
Mon Jan 20, 2020 6:09 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: q vs k
Replies: 9
Views: 51

### Re: q vs k

Yes Q is just the value of equilibrium at any given point and K is the equilibrium constant. When Q and K are equal, that would show you that the reaction is at equilibrium.
Mon Jan 20, 2020 6:07 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Directionality of Acid/Base Equations
Replies: 4
Views: 44

### Re: Directionality of Acid/Base Equations

In chemical equilibrium, most of the reactions will be reversible. A strong acid or base is able to completely dissociate in a solution and so the reaction is not reversible. However, a weak acid or base does not completely dissociate in a solution making the reaction reversible.
Mon Jan 20, 2020 6:06 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Endothermic vs Exothermic
Replies: 7
Views: 76

### Re: Endothermic vs Exothermic

If the ∆H is given a negative value means that the reaction is exothermic and a positive value means that the reaction is endothermic.
Mon Jan 20, 2020 6:05 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic Reactions
Replies: 4
Views: 40

### Re: Endothermic Reactions

An endothermic reaction means that there will be heat as a reactant since the reaction requires heat. Increasing the heat will therefore result in the formation of products since adding more heat will lead to more product formation.
Mon Jan 20, 2020 5:58 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Replies: 7
Views: 62

Adding a catalyst to a chemical equilibrium reaction will not affect the K value since a catalyst will only speed up the reaction so a reaction can occur quicker. It has no effect on the K value.
Tue Jan 14, 2020 12:28 pm
Forum: Ideal Gases
Topic: Molar Concentration
Replies: 4
Views: 47

### Re: Molar Concentration

It depends on the number of products or reactants that are present initially. If there is an initial amount, that number will decrease and those that start at 0 will increase.
Tue Jan 14, 2020 12:27 pm
Forum: Ideal Gases
Topic: Partial Pressure
Replies: 8
Views: 88

### Re: Partial Pressure

The partial pressure represents the it is the pressure of each individual gas of the chemical reaction. The total pressure would be the combined value of each individual gas in the reaction.
Tue Jan 14, 2020 12:26 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: volume and K value
Replies: 3
Views: 45

### Re: volume and K value

A change in volume will not affect the equilibrium constant value. It will shift the reaction to favor one side more but will not change K because the temperature is the only factor that is able to change the value of K.
Tue Jan 14, 2020 12:23 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: equilibrium constants and inputs
Replies: 4
Views: 57

### Re: equilibrium constants and inputs

We ignore liquids and solids since their concentrations do not change. We can then leave them out of the equations when we are solving for the K value.
Tue Jan 14, 2020 12:18 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Expansion
Replies: 5
Views: 36

### Re: Expansion

Yes I think it does since when they talk about expansion they are referring to the volume of the container. Since volume affects the reaction at equilibrium, so will expansion.
Wed Jan 08, 2020 8:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Partial Pressure of gas
Replies: 5
Views: 55

### Re: Partial Pressure of gas

Whatever the units are given in the problem are the units you should probably use unless you are asked to convert it into another unit.
Wed Jan 08, 2020 8:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: changing K
Replies: 4
Views: 58

### Re: changing K

Yes I think so since Kp and Kc are generally the same thing except one is used for reactions with aqueous solutions and the other is used for reactions with gases.
Wed Jan 08, 2020 8:20 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 6
Views: 334

### Re: Le Chatelier's Principle

Le Chatelier's Principle describes what happens to a reaction and what direction it will go in when the concentration of Q is greater than K (reverse reaction favored, more reactants) and when the concentration of Q is less than K (forward reaction favored, more products).
Wed Jan 08, 2020 8:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reverse reaction
Replies: 6
Views: 61

### Re: Reverse reaction

The reverse reaction will occur when Q is greater than K. When this happens the products are more abundant than the reactants in the reaction.
Wed Jan 08, 2020 7:02 pm
Forum: Ideal Gases
Topic: K and Q
Replies: 13
Views: 115

### Re: K and Q

The difference between K and Q is that K is only used when the reaction is at equilibrium and you know it is at equilibrium. Q, on the other hand, is when you are unsure whether the reaction is in equilibrium and you have to compare that value of Q to the K value that you will be given.
Tue Dec 03, 2019 9:40 pm
Forum: Amphoteric Compounds
Topic: how to determine
Replies: 3
Views: 45

### Re: how to determine

An amphoteric compound is one that has both acidic and basic characters. Because of this they resemble more metalloids that react with water which is why the diagonal band of amphoteric compounds is similar to the diagonal band of metalloids on the periodic table.
Tue Dec 03, 2019 9:37 pm
Forum: Hybridization
Topic: Energy levels in naming hybridizations
Replies: 2
Views: 45

### Re: Energy levels in naming hybridizations

I think the 2 is just indicating the energy level of the hybridized orbitals.
Tue Dec 03, 2019 9:36 pm
Forum: Biological Examples
Topic: Polydentate
Replies: 4
Views: 57

### Re: Polydentate

Polydentate is when a ligand can have multiple bonding sites to the transition metal. An example of this would be ethylenediamine (en) or diethylenetriamine (dien). Polydentates form chelates where the ligand forms a ring of atoms including the transition metal cations. These cations are bound tight...
Tue Dec 03, 2019 9:34 pm
Forum: Biological Examples
Topic: Vitamin B12
Replies: 3
Views: 64

### Re: Vitamin B12

Vitamin B12 is in relation to cobalt as a coordination compound. I think you just have to know that cobalt is a transition metal and this is one of its biological functions.
Tue Dec 03, 2019 9:33 pm
Forum: Naming
Topic: Iron vs Ferrate
Replies: 5
Views: 45

### Re: Iron vs Ferrate

The term ferrate is used when naming a coordination compound that has iron in it. More specifically, this coordination compound must have an anion.
Fri Nov 29, 2019 2:05 pm
Forum: Conjugate Acids & Bases
Topic: Definition of conjugate base
Replies: 6
Views: 303

### Re: Definition of conjugate base

The conjugate base is what is formed when an acid loses a hydrogen atom in a chemical equation. It is a base because it is a proton acceptor that receives an H atom from the proton donor or acid.
Fri Nov 29, 2019 1:59 pm
Forum: Lewis Acids & Bases
Topic: Lewis acid and base definition
Replies: 4
Views: 68

### Re: Lewis acid and base definition

A Lewis acid is a proton acceptor and a Lewis Base is a proton donor. Notice that this is different from the definition of bases and acids from the Bronsted-Lowry.
Fri Nov 29, 2019 1:55 pm
Forum: Lewis Acids & Bases
Topic: HCl vs HF
Replies: 19
Views: 223

### Re: HCl vs HF

HCl is a stronger acid than HF because Cl has a larger atomic radius than F therefore the bond between the H and Cl would be longer than in HF. This makes the bond weaker since it is longer making it easier to break the bond between HCl compared to HF. The bond will dissociate more in HCl than in HF...
Fri Nov 29, 2019 1:52 pm
Forum: Bronsted Acids & Bases
Topic: Acid vs Base
Replies: 4
Views: 82

### Re: Acid vs Base

Since the Bronsted acids are proton donors, you can usually identify them with an H at the beginning of the molecule. The Bronsted bases are proton acceptors and usually consist of a hydroxide group
Fri Nov 29, 2019 1:49 pm
Forum: Bronsted Acids & Bases
Topic: Difference between bronsted and lewis acid/base?
Replies: 6
Views: 56

### Re: Difference between bronsted and lewis acid/base?

I think you just need to understand the differences between a bronsted acid/base and a lewis acid/base. Bronsted acids are those that are proton donors and bronsted bases are proton acceptors. However, Lewis acids are proton acceptors and Lewis bases are proton donors.
Fri Nov 22, 2019 9:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: NO Shape and Polarity
Replies: 4
Views: 74

### Re: NO Shape and Polarity

NO would have a linear shape since there are only 2 regions of electron density. It would also be polar since there's a difference in electronegativity between the N and O atoms. This would lead to a partial negative charge for the O leading to the molecule being polar.
Fri Nov 22, 2019 9:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE Format
Replies: 34
Views: 281

### Re: AXE Format

I think writing only X or E is fine when there is only one.
Fri Nov 22, 2019 9:42 am
Forum: Determining Molecular Shape (VSEPR)
Topic: name?
Replies: 4
Views: 57

### Re: name?

Bent and angular have the same shape but the bond angles might be different for both. Bent usually has two lone pairs whereas angular has one so the bond angles would be less in bent than in angular.
Fri Nov 22, 2019 9:40 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: boiling point of ionic compounds
Replies: 3
Views: 45

### Re: boiling point of ionic compounds

NaCl would have a higher boiling point than HCl since it has ion-ion intermolecular forces compared to the dipole-dipole forces of HCl. These ion-ion forces makes the molecule an ionic molecule whereas HCl would be covalent. Therefore, since ionic bonds are stronger specifically ion-ion forces, the ...
Mon Nov 18, 2019 10:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: resonance structures in molecular structures
Replies: 4
Views: 44

### Re: resonance structures in molecular structures

Yes since the number of bonds in a molecule whether that be single, double, or triple all equal a single electron density region resonance structure won't matter.
Tue Nov 12, 2019 7:28 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: Boiling and Melting Points
Replies: 7
Views: 62

### Re: Boiling and Melting Points

A stronger intermolecular force will have a greater boiling or melting point. This is because since the bonds are stronger, they are harder to break apart. Increasing the polarizability of a molecule will create a stronger interaction leading to a higher boiling and melting point.
Tue Nov 12, 2019 5:47 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: 3
Views: 40

### Re: 3F.15

The boiling point of AsF3 will be higher than AsF5 since based on the Lewis structures you can determine that AsF3 is polar and AsF5 is nonpolar based on a net partial negative charge. Thus the dipole-dipole interactions for AsF3 will be stronger than AsF5 causing the boiling point to be higher.
Tue Nov 12, 2019 5:44 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: Help of 3F.11
Replies: 5
Views: 58

### Re: Help of 3F.11

It might be helpful to draw the Lewis Structures of each molecule. From there you can see which molecules have a hydrogen bonded to N, O, or F atoms. This indicates that there is a hydrogen bond in that particular molecule.
Tue Nov 12, 2019 5:43 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.5 [ENDORSED]
Replies: 4
Views: 127

### Re: 3F.5[ENDORSED]

By drawing the Lewis Structure of each molecule you are then able to determine the type of intermolecular forces in each molecule. The molecules with stronger intermolecular interactions will then have a higher melting point than those molecules that are weaker.
Tue Nov 12, 2019 5:40 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: melting points
Replies: 5
Views: 43

### Re: melting points

NaCl will have a higher melting point than HCl since NaCl is an ionic bond and HCl is a covalent bond. Ionic bonds are generally stronger than a covalent bond so it takes more to break apart these bonds than those in covalent molecules.
Tue Nov 05, 2019 3:00 pm
Forum: Dipole Moments
Topic: Polar Covalent Bonds
Replies: 2
Views: 34

### Re: Polar Covalent Bonds

The electrons would not be equally shared since one of the atoms in the molecules is more electronegative than the other. Thus that particular atom will pull electrons more strongly than the other atom and would lead to an unequal distribution of charges leading the molecule to be polar covalent.
Tue Nov 05, 2019 2:58 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Power Periodic Trend
Replies: 4
Views: 55

### Re: Polarizing Power Periodic Trend

Polarizing power is usually associated with cations. The usual trend for this is similar to atomic radius in the sense that polarizing power increases as the size of the atom increases. Therefore, down a group the polarizing power increases and decreases as you go across a period.
Tue Nov 05, 2019 2:56 pm
Forum: Octet Exceptions
Topic: noble gas bonding
Replies: 3
Views: 53

### Re: noble gas bonding

Noble gases like Xe can bond with other atoms since it has an expanded valence shell and thus have an empty d-orbital. This allows the atom to add more electrons into that d-orbital.
Tue Nov 05, 2019 2:54 pm
Forum: Resonance Structures
Topic: Bond lengths
Replies: 11
Views: 138

### Re: Bond lengths

All the bond lengths are the same because in resonance structures the bond lengths are an average of every single bond leading them to all be the same length.
Tue Nov 05, 2019 2:52 pm
Forum: Octet Exceptions
Replies: 2
Views: 45

I think if you are looking for the most stable form of the molecule then you should put the radical on the oxygen since it is more electronegative. For most resonance structures we always used electronegativities to determine if the particular arrangement would be the most stable form.
Tue Oct 29, 2019 2:22 pm
Forum: Trends in The Periodic Table
Topic: Electronegativity vs Electron Affinity
Replies: 6
Views: 91

### Re: Electronegativity vs Electron Affinity

Electronegativity is the ability of atoms to attract electrons and it increases across the period and decreases down a group. Electron affinity is the energy released when electrons are added to a gaseous atom it also has the same trend as electronegativity on the periodic table.
Tue Oct 29, 2019 2:18 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 4
Views: 77

### Re: Formal Charge

You should calculate the formal charge of the structures to find which structure would be the most stable. The formal charge will then tell you if the structure is stable if the number is closest to 0.
Tue Oct 29, 2019 2:15 pm
Forum: Electronegativity
Topic: Electronegativity vs ionization energy
Replies: 7
Views: 447

### Re: Electronegativity vs ionization energy

The electronegativity is the ability of atoms to attract electrons whereas ionization energy is how well the atom holds valence electrons. The ionization energy is the energy required to remove electrons from a gaseous atoms.
Tue Oct 29, 2019 2:11 pm
Forum: Trends in The Periodic Table
Replies: 3
Views: 68

For the most part the ionic radius does follow the same trend as the atomic radius. Both the atomic radius and the ionic radius decrease across periods and increase as you go down the group. This is because across the period increased protons leads to an increased positive charge which pulls electro...
Tue Oct 29, 2019 2:04 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 3
Views: 37

### Re: Ionization Energy

The 2nd ionization energy is greater than the first since successive ionizations are bigger. This is because removing a 2nd electron is harder than removing the first electrons since there's less electron repulsion.
Sat Oct 26, 2019 7:29 pm
Forum: Lewis Structures
Topic: Anion
Replies: 7
Views: 98

### Re: Anion

Typically you would represent that it's an anion by adding a negative sign in the top right hand corner after the brackets.
Sat Oct 26, 2019 7:26 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 5
Views: 80

### Re: Lewis Structure

The element with the lowest ionization energy will be the central atom for the Lewis Structure.
Sat Oct 26, 2019 7:25 pm
Forum: Trends in The Periodic Table
Topic: bond length
Replies: 9
Views: 120

### Re: bond length

I'm not completely sure whether we have to know how to calculate it but I think you do need to know the different bond lengths of bond types. A triple bond would be the shortest and double would be the next shortest and then a single bond would be the longest.
Wed Oct 23, 2019 9:22 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy of Electrons
Replies: 6
Views: 76

### Re: Energy of Electrons

The energy of an electron increases when it moves up an energy level. This is because the electron goes to a higher energy state and are excited by an external energy source which allows them to move up the energy level.
Wed Oct 23, 2019 9:15 am
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 76

### Re: Schrodinger Equation

That is the symbol psi and represents the height of the wave and the state of the wave-particle.
Fri Oct 18, 2019 11:04 am
Forum: Photoelectric Effect
Topic: Problem 1B.3
Replies: 4
Views: 68

### Re: Problem 1B.3

The photoelectric effect is the correct answer because in that experiment they were able to find that there would be more electrons ejected from a piece of metal if the frequency of the light is increased. They tried to increase the intensity of the particular light source and the same amount or no ...
Fri Oct 18, 2019 11:00 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: What does the equation actually show?
Replies: 3
Views: 37

### Re: What does the equation actually show?

The Heisenberg Indeterminacy Equation is used to figure out where the location of an electron could be in an atom. The calculation compares the change in momentum and position of the electron and compares that number to the speed of light.
Tue Oct 15, 2019 3:54 pm
Forum: Properties of Electrons
Topic: Using masses of protons, neutrons, and electrons
Replies: 7
Views: 138

### Re: Using masses of protons, neutrons, and electrons

I went to one of the UA sessions and they gave us a constants and equations sheet for practice problems. On that sheet was the masses of protons, neutrons, and electrons so I'm assuming that we don't need to know these values.
Tue Oct 15, 2019 3:53 pm
Forum: Properties of Light
Topic: Relationships
Replies: 3
Views: 73

### Re: Relationships

Light is a form of energy. However, light is made up of photons which are light particles that form light. Both light and photons consist of energy.
Mon Oct 14, 2019 9:32 pm
Forum: Einstein Equation
Topic: Einstein's Equation
Replies: 7
Views: 89

### Re: Einstein's Equation

The photoelectric effect is defined as E(Photon) - threshold E = Kinetic energy of the electron. In order for an electron to be ejected and have KE, the E(Photon) has to be greater than the threshold energy of the metal. If the E(Photon) and threshold energy are equal an electron will be removed but...
Mon Oct 14, 2019 9:28 pm
Forum: Photoelectric Effect
Replies: 7
Views: 87

### Re: Question about Energy Threshold

If the light source's energy does not pass the energy threshold the electrons won't be ejected since E(Photon) is less than the threshold energy. If the E(Photon) and the threshold energy are equal then the electron will be released but will have no kinetic energy.
Mon Oct 14, 2019 9:26 pm
Forum: Photoelectric Effect
Topic: Frequency vs. Amplitude: Intensity?
Replies: 3
Views: 45

### Re: Frequency vs. Amplitude: Intensity?

Amplitude does not have an effect on the intensity of the wave. Frequency, however, does have an effect on the intensity of the wave and is more important for the photoelectric effect. Frequency relates to the number of photons and the energy within each of these photons. An increased frequency can ...
Wed Oct 09, 2019 10:52 am
Forum: Molarity, Solutions, Dilutions
Topic: Help with Textbook problem G.21
Replies: 2
Views: 93

### Re: Help with Textbook problem G.21

To find the concentration of the individual ions you take the moles of each compound and multiply it by the mole ratio of the ions in that compound. This will leave you with the number of moles of the particular ion. From there you are able to use the molarity equation c = n/v (where n is the calcul...