## Search found 105 matches

Sat Mar 14, 2020 9:48 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Midterm Q.3B
Replies: 2
Views: 127

### Re: Midterm Q.3B

a higher difference in concentrations would mean that a reaction between the two would probably be stronger and have a greater change in temperature.
Sat Mar 14, 2020 9:46 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: + or - w
Replies: 2
Views: 108

### Re: + or - w

when work is done on the system it is + and when work is done BY the system it is -. I think in physics, they use the opposite equation where U=q-w which is why that might be opposite, but in chem we use U=q+w.
Sat Mar 14, 2020 9:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration cells
Replies: 2
Views: 61

### Re: Concentration cells

even if you have cases where the cathode is lower, Q=[anode]/[cathode]
Sat Mar 14, 2020 9:42 pm
Forum: Ideal Gases
Topic: T variable in pv=nrt
Replies: 10
Views: 111

### Re: T variable in pv=nrt

you should probably always keep it in Kelvin just to be safe because if it cancels out it won't matter anyways.
Sun Mar 08, 2020 10:19 pm
Forum: General Rate Laws
Topic: Effect on rxn rate
Replies: 2
Views: 27

### Effect on rxn rate

How do you know how the rate of a reaction will be affected if you double/halve/ etc. the amount of a product or reactant?
Sun Mar 08, 2020 10:18 pm
Forum: General Rate Laws
Topic: units
Replies: 12
Views: 120

### Re: units

the units will depend on the rate law and the order of the reaction because that will influence the power to which the units are multiplied. I would find the answer and then write out the formula with just the units to calculate/find what those would be.
Sun Mar 08, 2020 10:15 pm
Forum: First Order Reactions
Topic: Graphing 1st order reaction rates
Replies: 6
Views: 50

### Re: Graphing 1st order reaction rates

because you want to look at the equation like an mx+b equation so that it's easier to graph. In this case, the ln[A] is the b.
Sun Mar 08, 2020 10:12 pm
Forum: *Electrophiles
Topic: final
Replies: 7
Views: 807

### Re: final

might be extra thermo on there since we didn't cover it that much on the midterm
Sun Mar 08, 2020 10:11 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 73
Views: 3995

Hannah's peer learning sessions in young are great!
Sun Mar 08, 2020 10:11 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Replies: 73
Views: 3995

you should try to go to the peer learning sessions in young during the day! you can usually fit them in in between classes and there are never that many people.
Sun Mar 08, 2020 10:06 pm
Forum: Balancing Redox Reactions
Topic: Why do we flip E for oxidation?
Replies: 13
Views: 111

### Re: Why do we flip E for oxidation?

If you are just using the cathode - anode equation you don't need to flip any numbers because the minus sign takes care of that. But, if you are using the method of writing out the half reactions and making the net equation, you'll have to make sure you flip the E for the oxidation half reaction.
Sun Mar 08, 2020 10:04 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Instantaneous Rate
Replies: 13
Views: 186

### Re: Instantaneous Rate

If you look at the curve graph for the concentration v. time, you can tell that the rate is very quick at first when the concentration is high and decreases as time increases.
Sun Mar 08, 2020 10:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 6
Views: 66

### Cell Diagrams

How do you format a cell diagram when the states are the same v. when the elements are in different states?
Sun Mar 01, 2020 11:03 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: instantaneous rate
Replies: 16
Views: 200

### Re: instantaneous rate

because it is more accurate since you can get the rate of a reaction at a certain time by taking the slope of a tangent line
Sun Mar 01, 2020 11:00 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell notation
Replies: 2
Views: 45

### Re: Cell notation

you should only leave out the Pt because you're only adding that in the cell diagram when you have all aqueous/ gaseous solutions. All other elements in the cell diagram should usually be included.
Sun Mar 01, 2020 10:55 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M.1 reversed anode and cathode?
Replies: 3
Views: 41

### Re: 6M.1 reversed anode and cathode?

even though the book wrote the cell diagram like that, you have to look at what is being reduced/ oxidized and then rewrite the cell diagram based on that. Also since the given Ecell is negative, you know that the given isn't spontaneous so you need to switch the Cu and M to make it spontaneous.
Sun Mar 01, 2020 10:53 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 8
Views: 139

### Re: Anode and Cathode

the anode is also drawn on the left of a cell picture and on the left of a cell diagram.
Sun Mar 01, 2020 10:52 pm
Forum: Administrative Questions and Class Announcements
Topic: what to know for test 2
Replies: 10
Views: 137

### Re: what to know for test 2

up until the beginning of lecture on Wednesday
Sun Feb 23, 2020 9:44 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gp=Gr
Replies: 3
Views: 80

### Re: Gp=Gr

If the rates of reactions are the same, the free energies on both sides of the equation should be the same.
Sun Feb 23, 2020 9:41 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Test 2
Replies: 13
Views: 119

### Test 2

What topics/outlines is Test 2 going to be on?
Sun Feb 23, 2020 9:40 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst
Replies: 7
Views: 77

### Nernst

What do all of the variables in the Nernst equation mean?
Sun Feb 23, 2020 9:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams
Replies: 2
Views: 60

### Cell Diagrams

Can someone explain what each part of the galvanic/voltaic cell is and what function it serves (ex. salt bridge)?
Sun Feb 23, 2020 9:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Potentials
Replies: 2
Views: 46

### Cell Potentials

Which method/ equation can we use without changing the signs of the cathode/anode?
Thu Feb 20, 2020 12:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Purpose of Salt Bridge
Replies: 12
Views: 130

### Re: Purpose of Salt Bridge

Since e- move from left to right, eventually, the e- would build up on the right side and that would cause the battery to stop working/ make the e- stop moving. To avoid this, the salt bridge allows for the movement of ions so that e- don't build up on the right side.
Sun Feb 16, 2020 9:44 pm
Forum: Biological Examples (*DNA Structural Transitions, etc.)
Topic: organic reactions, and environmental and biological examples
Replies: 4
Views: 134

### Re: organic reactions, and environmental and biological examples

I think he talked about biological examples with glycolysis/ cellular respiration and energy production
Sun Feb 16, 2020 9:43 pm
Forum: Administrative Questions and Class Announcements
Topic: HW7
Replies: 14
Views: 172

### Re: HW7

usually you should choose from the outline that we left off on/ were recently on
Thu Feb 13, 2020 9:30 pm
Forum: Phase Changes & Related Calculations
Topic: Relation to entropy?
Replies: 4
Views: 113

### Re: Relation to entropy?

going from a liquid to a gas also has greater entropy increase than going from a solid to a liquid
Thu Feb 13, 2020 8:24 pm
Forum: Calculating Work of Expansion
Topic: Last Question on the Midterm [ENDORSED]
Replies: 5
Views: 193

### Re: Last Question on the Midterm[ENDORSED]

I think the last question was about finding entropy in both an irreverisble and reversible expansion. You approach both using the entropy formula (i believe it was the change in volume formula) but this will only give you the answer to deltaS. To find deltaSsurrounding and deltaStotal you had to kno...
Tue Feb 11, 2020 9:20 pm
Forum: Administrative Questions and Class Announcements
Replies: 67
Views: 2925

Can someone show me step by step on how to solve for number 10. I did not understand why q(ice)=q(water). CHEM MOD: q(ice) = -q(water) DO NOT forget the negative sign. The heat released from one material in a system is absorbed by the other material in the system. For #10, why do we have to convert...
Sun Feb 09, 2020 10:53 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: reversible reactions
Replies: 4
Views: 47

### Re: reversible reactions

i'm pretty sure it should always tell us reversible or irreversible to indicate which equation to use.
Sun Feb 09, 2020 10:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: work on the system or by the system
Replies: 4
Views: 42

### Re: work on the system or by the system

if you use deltaU=q+w then w is negative when work is done by the system and w is positive when work is done on the system (if you are taking the perspective of the system)
Sun Feb 09, 2020 10:46 pm
Forum: Calculating Work of Expansion
Topic: integration
Replies: 2
Views: 36

### integration

do we ever need to use the integral for calculating work of expansion or can we always use the equation w/o it?
Sun Feb 09, 2020 10:44 pm
Forum: Calculating Work of Expansion
Topic: Isothermal
Replies: 17
Views: 170

### Re: Isothermal

along with isothermal, i think we also need to isobaric (constant pressure) and isochoric (constant volume)
Sun Feb 09, 2020 10:39 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Gas v Liquids
Replies: 4
Views: 51

### Re: Gas v Liquids

for the reasons above liquids also have higher entropy than solids so entropy increases from the solid state to liquid state to gaseous state.
Thu Jan 30, 2020 6:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law vs. Standard Enthalpies of Formation
Replies: 5
Views: 78

### Re: Hess's Law vs. Standard Enthalpies of Formation

I'm pretty sure that we will be given the multiple rxns and their enthalpies for Hess's Law.
Thu Jan 30, 2020 6:30 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Work of expansion equation
Replies: 4
Views: 46

### Work of expansion equation

Why do we add a negative in the work of expansion at constant pressure equation?
Thu Jan 30, 2020 6:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Changing the energies of systems
Replies: 2
Views: 34

### Changing the energies of systems

Can someone review how you can change the energies of the three types of systems?
Thu Jan 30, 2020 6:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Work done by expansion
Replies: 8
Views: 62

### Work done by expansion

Did we go over the equation for work done by expansion when P is not constant? Is that the same work equation with the integral included?
Thu Jan 30, 2020 6:24 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Value of q
Replies: 11
Views: 140

### Value of q

In a perfect system, what would/ should the values of q be?
Sun Jan 26, 2020 7:29 pm
Forum: Phase Changes & Related Calculations
Topic: State Property
Replies: 3
Views: 21

### Re: State Property

enthalpy is a state property which is a property that is not dependent on the path taken to obtain that state. This means that state properties can be added or subtracted and this like work or heat are not state properties.
Sun Jan 26, 2020 7:28 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Using Method 2
Replies: 2
Views: 27

### Re: Using Method 2

i think the method you use just depends on the information you are given and since bond enthalpy values are usually something you can look up/ would be given, you could use this method if you are not given the information for Hess's Law.
Sun Jan 26, 2020 7:24 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 3
Views: 26

### Re: Enthalpy

enthalpy is the study of heat released or absorbed in chemical reactions and physical changes --> the amount of heat released or absorbed at a constant pressure is called enthalpy
Sun Jan 26, 2020 7:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Friday Lecture
Replies: 2
Views: 24

### Re: Friday Lecture

The third method was just using the formula where you sum the standard enthalpy of formation of the products and subtract the sum of the standard enthalpy of formation of the reactants from that.
Sun Jan 26, 2020 7:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law
Replies: 9
Views: 138

### Re: Hess's Law

Hess's Law shows you that enthalpy changes are additive because enthalpy change at each stage can be added to give total enthalpy change.
Thu Jan 16, 2020 5:02 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Product Yield
Replies: 6
Views: 64

### Product Yield

How would you change the yield of a product without adding more reactants?
Thu Jan 16, 2020 4:54 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Replies: 11
Views: 101

How do you do the calculations for the ICE table without using the quadratic formula?
Thu Jan 16, 2020 4:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Acids and Bases
Replies: 2
Views: 31

### Acids and Bases

How does the concentration change when the pH value changes by a certain value?
Thu Jan 16, 2020 4:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in Equilibrium Constant Eq.
Replies: 3
Views: 26

### Water in Equilibrium Constant Eq.

With acid and base equilibrium reactions, why do you not include water in the equilibrium constant equation?
Thu Jan 16, 2020 4:48 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic and exothermic
Replies: 5
Views: 71

### Re: Endothermic and exothermic

If the reaction gives off heat while forming the product, then the heating will favor reactant formation (because additional heat is used) and this is exothermic.
Thu Jan 09, 2020 6:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Values of K
Replies: 3
Views: 30

### Values of K

Can someone summarize what the different ranges and values of K mean for the reactants and products?
Thu Jan 09, 2020 5:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook 5H.1 Part 1
Replies: 4
Views: 32

### Re: Textbook 5H.1 Part 1

you want to take the square root because you want to manipulate the K equation for part (B) and make it look like the K equation for the original given reaction.
Thu Jan 09, 2020 5:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework Question 5H.1
Replies: 2
Views: 29

### Re: Homework Question 5H.1

For (B) first write out the K for this equation. When you write it out, you can see that this K looks almost similar to the K of the original given reaction. The only difference is the power to which each product and reactant is raised. If you multiplied the powers from the original K times 1/2, you...
Thu Jan 09, 2020 5:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.11
Replies: 4
Views: 50

### Re: 5G.11

You only want to include the product and reactant that are in the gaseous or aqueous state. Since the other products and reactants are solids and liquids you don't use them in your calculation of Q.
Thu Jan 09, 2020 5:52 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K pressure units
Replies: 3
Views: 31

### Re: K pressure units

If you are looking for Kp then he said to write the units as atm.
Fri Dec 06, 2019 12:06 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6C. 19 f)
Replies: 1
Views: 19

### Re: 6C. 19 f)

because C is more electronegative, it is better at pulling and the O-H bond is easier to break. since this conjugate base is weaker/easier to break, its acid is stronger.
Fri Dec 06, 2019 12:05 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C.17
Replies: 2
Views: 39

### Re: 6C.17

a strong base will come from a weaker acid so draw the conjugate bases for the given and see which one is a weaker acid.
Fri Dec 06, 2019 12:03 am
Forum: Hybridization
Topic: Determining Hybridization
Replies: 4
Views: 51

### Re: Determining Hybridization

look at regions of electron density and create orbitals based on that number.
Thu Dec 05, 2019 10:49 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Resonance and Acidity
Replies: 2
Views: 69

### Re: Resonance and Acidity

When the conjugate base of an acid is more electronegative, it is better at pulling so the O-H bond is easier to break. This means the conjugate base is weak and it's acid is stronger.
Thu Dec 05, 2019 10:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination #
Replies: 6
Views: 149

### Re: Coordination #

coordination # is the # of ligand molecules attached to the transition metal ion.
Sat Nov 30, 2019 7:51 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak Acids & Bases
Replies: 6
Views: 129

### Re: Weak Acids & Bases

Benzoic acid is also a weak acid and you can remember this because the COOH in benzoic acid is often found in biological molecules and organic acids tend to be weaker.
Sat Nov 30, 2019 7:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: drawing
Replies: 1
Views: 46

### drawing

What steps do you go through to draw a coordination compound?
Sat Nov 30, 2019 7:45 pm
Forum: Biological Examples
Topic: Chemotherapy
Replies: 6
Views: 116

### Chemotherapy

What are some examples of coordination compounds used as chemotherapy drugs?
Sat Nov 30, 2019 7:37 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: strong or weak base?
Replies: 13
Views: 222

### Re: strong or weak base?

A weak base will partially dissociate but a strong base fully dissociates to give ions in a solution. Weak bases also have pH from 7 to 10 and strong ones have pH 10 to 14.
Sat Nov 30, 2019 7:35 pm
Forum: Naming
Topic: Coordination Compounds on the Final
Replies: 4
Views: 74

### Re: Coordination Compounds on the Final

We only really learned how to name them so I would probably just focus on/study that.
Tue Nov 19, 2019 8:42 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: 1
Views: 53

### Boiling and Melting Points

Can someone explain how to go about checking which molecules have the highest boiling points in a series? What steps do I take/ things that I check to put the molecules in the correct order?
Tue Nov 19, 2019 8:38 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Hydrogen Bonding/Pi bonds
Replies: 11
Views: 312

### Re: Hydrogen Bonding/Pi bonds

Intermolecular forces:
ionic bonding --> H-bonding --> dipole-dipole bonding --> induced dipole/London dispersion
Tue Nov 19, 2019 8:36 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: Hydrogen bonding
Replies: 3
Views: 53

### Re: Hydrogen bonding

Since N, O, and F all have super high electronegativity and H has a low electronegativity, they can have have a dipole moment between the atoms. --> you need the H because it's low electronegativity corresponds to the N, O, and F's high electronegativity.
Tue Nov 19, 2019 8:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Effect of lone pair on bond angles
Replies: 2
Views: 55

### Re: Effect of lone pair on bond angles

Yes it's because the actual atom is bigger so it's going to slightly decrease the bond angles by making the other atoms be a little closer together.
Fri Nov 15, 2019 5:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula Exceptions
Replies: 6
Views: 134

### Re: VSEPR Formula Exceptions

We probably don't have to deal with *exceptions* but still have to consider the changes when lone pairs are added or when different bonding atoms are changed.
Fri Nov 15, 2019 5:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E problem #13b.
Replies: 3
Views: 73

### Re: 2E problem #13b.

I believe sometimes the bond angles can be slightly influenced if one bonding atom is significantly bigger than the other three bonding atoms, but in this context I think we only need to demonstrate a change in bond angles with the presence of a lone pair.
Fri Nov 15, 2019 5:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How to tell polar or non polar from lewis structure?
Replies: 9
Views: 154

### Re: How to tell polar or non polar from lewis structure?

If you have the lewis structure, you can draw your dipole arrows considering electronegativity and if the arrows don't balance out then the molecule will be polar.
Fri Nov 15, 2019 5:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape v Electron Geometry
Replies: 4
Views: 66

### Re: Molecular Shape v Electron Geometry

With the electron geometry, all you have to consider is the number of things attached to the central atoms (lone pairs, atoms) to determine what the shape/geometry would be. When determining the molecular shape, you build off of this and determine how many of the "attached things" are lone...
Fri Nov 15, 2019 5:10 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: Molecule Size and Melting Points
Replies: 6
Views: 62

### Re: Molecule Size and Melting Points

Bigger molecules do have higher boiling points but the shape of the molecule also can influence boiling point. For example, molecules with the same molecular formula but different shapes (branched vs. linear) can have different BPs.
Fri Nov 08, 2019 2:00 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: Distinguishing between the different intermolecular forces
Replies: 9
Views: 426

### Re: Distinguishing between the different intermolecular forces

Hydrogen bonding is easy to see because it is present in molecules with N, O, F atoms. The N, O, or F atoms have to have lone pairs available and then and H atom covalently bonded to the electronegative atom and close to another electronegative atom.
Fri Nov 08, 2019 1:57 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Polarizability and States
Replies: 3
Views: 154

### Polarizability and States

What is the relationship between polarizability and the states of atoms/molecules?
Fri Nov 08, 2019 11:50 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: Electron Distortion
Replies: 2
Views: 30

### Electron Distortion

What is the relationship between electron distortion and polarizability of the electron?
Fri Nov 08, 2019 11:49 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: Interaction Potential Energy
Replies: 3
Views: 72

### Interaction Potential Energy

Why is the interaction potential energy always negative?
Fri Nov 08, 2019 11:48 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: Interaction Potential Energy
Replies: 3
Views: 52

### Interaction Potential Energy

Can someone explain the components of the formula for interaction potential energy and what the alpha and r means?
Wed Oct 30, 2019 11:58 pm
Forum: Trends in The Periodic Table
Topic: Shielding and Electron Replusion
Replies: 3
Views: 75

### Re: Shielding and Electron Replusion

shielding occurs across energy levels because the electrons in the energy levels that are closer to the nucleus block the electrons higher up from receiving the full charge. electron-electron repulsion occurs within the same energy level because when there are multiple electrons, they push each othe...
Wed Oct 30, 2019 11:51 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.19
Replies: 3
Views: 126

### Re: 1D.19

to find orbitals you would use ml. the values can range from -l to +l so you would need to find l from n and then find the values for ml.
Wed Oct 30, 2019 11:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: When do you use a negative sign in the Bohr equation?
Replies: 7
Views: 96

### Re: When do you use a negative sign in the Bohr equation?

the negative is always there in the equation because if we say that as n --> infinity, that E is 0, as the electron comes back down from high energy levels and approaches the nucleus, it loses energy and the values for energy are "negative." in a review session, a good analogy used was ......
Wed Oct 30, 2019 11:41 pm
Forum: Photoelectric Effect
Topic: Increasing Light Intensity Photoelectric Effect
Replies: 7
Views: 91

### Re: Increasing Light Intensity Photoelectric Effect

frequency determines whether or not electrons are emitted. the intensity increases the number of photons but not that actual energy.
Wed Oct 30, 2019 11:39 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Why does formal charge indicate stability?
Replies: 3
Views: 84

### Re: Why does formal charge indicate stability?

since formal charge indicates the gain/loss of electrons while forming a covalent bond, it serves as a predictor for stability in a lewis structure. The structure with the least formal charge should be lower in energy and thereby be the better Lewis structure.
Tue Oct 22, 2019 11:18 am
Forum: Trends in The Periodic Table
Replies: 10
Views: 151

Why are anions much bigger than their parent atoms/ why are cations much smaller?
Tue Oct 22, 2019 11:15 am
Forum: Trends in The Periodic Table
Topic: Effective Nuclear Charge
Replies: 7
Views: 53

### Re: Effective Nuclear Charge

example: with oxygen (+8), the outer electrons are being blocked from the full charge by the inner electrons. the inner electrons shield the outer electrons from the electrostatic attraction of a positive nucleus. the outer electrons feel a reduced electrostatic attraction and this results in an eff...
Tue Oct 22, 2019 11:12 am
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 4
Views: 57

### Re: Electron Affinity

going off the previous answer, there is a high electron affinity for elements in the top right of the periodic table so it follows a similar trend to ionization energy in that it decreases down and group and increases across a period. this does exclude noble gases though because adding an electron t...
Tue Oct 22, 2019 11:09 am
Forum: Trends in The Periodic Table
Topic: Ionization Energy Across a Period
Replies: 3
Views: 23

### Ionization Energy Across a Period

I get that as you go down a group, the electrons get further away from the nucleus and are shielded by the inner electrons so the ionization energy decreases. Why does ionization energy increase across a period?
Tue Oct 22, 2019 11:06 am
Forum: Trends in The Periodic Table
Topic: 2nd Ionization Energy
Replies: 7
Views: 61

### Re: 2nd Ionization Energy

Something to also consider: the 1st ionization energy is easier because the atom would be neutral and when you remove an electron, the charge becomes positive and the attraction on that 2nd electron would be higher
Fri Oct 18, 2019 11:19 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: removing electrons
Replies: 5
Views: 373

### Re: removing electrons

You would need to pull from the outermost electrons so if you had 4d10 5s2 5p1 you would pull or add from 5p1 first and then if you need to pull more you would move on to 5s2. Pay attention to the numbers out in front of the orbitals and pull from the highest number first.
Fri Oct 18, 2019 11:15 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: ION WITH +1
Replies: 4
Views: 362

### Re: ION WITH +1

You would normally find the electron configuration and pretend like it does not have a + or -. After finding the normal electron configuration, you can go in and add or remove an electron. The only time you would not be able to look for the normal configuration in the periodic table is if you were l...
Fri Oct 18, 2019 11:08 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Total Coulombic potential energy
Replies: 2
Views: 57

### Re: Total Coulombic potential energy

electrostatic potential energy is proportional to/ depends on ((q1)(q2))/ r where q1 is the charge 1, q2 is the charge 2, and r is distance. electrostatic energy goes up when the charge of the nucleus goes up and and goes down when the distance goes up because E and r are inversely proportional.
Tue Oct 15, 2019 8:41 pm
Forum: Properties of Light
Replies: 3
Views: 44

What is the arrangement of following types of photons of electromagnetic radiation in order of increasing energy: g-rays, visible light, ultraviolet radiation, microwaves, x-rays?
Tue Oct 15, 2019 8:22 pm
Forum: DeBroglie Equation
Topic: De Broglie's Equation
Replies: 17
Views: 272

### Re: De Broglie's Equation

De Broglie suggested that the equation works for any particle with momentum, that has a rest mass, and has wavelike properties.
Fri Oct 11, 2019 11:40 am
Forum: DeBroglie Equation
Topic: exhibiting wave-like properties
Replies: 4
Views: 398

### Re: exhibiting wave-like properties

In lecture today, it was said that a particle with less than 10^-15m wavelength does not have detectable wavelength properties. If the mass is higher, it will have a smaller wavelength and therefore is more likely to only have particle-like behavior and not wave-like behavior.
Fri Oct 11, 2019 11:37 am
Forum: DeBroglie Equation
Topic: Measurable V. Non-Measurable
Replies: 5
Views: 83

### Measurable V. Non-Measurable

What wavelength values from De Broglie's equation indicate whether or not a particle or electron has detectable wavelength properties?
Fri Oct 11, 2019 11:34 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy and Precision
Replies: 8
Views: 238

### Re: Accuracy and Precision

accuracy indicates how close measurements are to the "true" or real value and precision indicates how close measurements are to each other, but not necessarily to the "true" value.
Thu Oct 10, 2019 1:27 am
Forum: Properties of Electrons
Topic: Atomic Spectra and Energy Levels
Replies: 5
Views: 63

### Atomic Spectra and Energy Levels

can someone elaborate on how spectroscopic analysis of light can be used to identify different elements?
Thu Oct 10, 2019 1:24 am
Forum: SI Units, Unit Conversions
Topic: Angstrom
Replies: 16
Views: 472

### Re: Angstrom

^ Also remember that we will get a formula/constants sheet for every test so a lot of the information we need will be given to us. There's no harm in memorizing though!
Thu Oct 10, 2019 1:20 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency Condition
Replies: 1
Views: 50

### Bohr Frequency Condition

Can someone explain how to do one of the learning outcomes in this section. It says we should know how to use the Bohr frequency condition to explain the origin of the lines in the spectrum of an element.
Thu Oct 10, 2019 1:07 am
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 11
Views: 235

### Re: Test 1

^^ I would recommend pulling up the Review/Outline for Fundamentals that's on the website. Just go through the key concepts and make sure you know how to do a couple of types of problems from each bullet point.