Search found 87 matches

by Lucian1F
Wed Mar 14, 2018 4:17 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Question 15.63
Replies: 2
Views: 150

Re: Question 15.63

For this question and problems like this where two rate constants at two different temperatures for the same reaction and the activation energy is given as well, use the Arrhenius equation to find the answer.
by Lucian1F
Tue Mar 13, 2018 6:53 pm
Forum: General Rate Laws
Topic: 15.19 solving for K
Replies: 2
Views: 110

Re: 15.19 solving for K

The book changed the mmol to mol in this problem I believe.
by Lucian1F
Tue Mar 13, 2018 6:51 pm
Forum: Administrative Questions and Class Announcements
Topic: Test Grading
Replies: 4
Views: 356

Re: Test Grading

I don't remember him saying anything about dropping our lowest test. Maybe you're thinking of another class?
by Lucian1F
Mon Mar 05, 2018 8:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2 Question 7
Replies: 1
Views: 106

Re: Test 2 Question 7

The reaction the question asks you to calculate the standard potential for is actually Cr(s), not Cr3+. So, you need to use the equation you mentioned and also 2Cr3+ + 6e- -> 2Cr(s). However, the same species (Cr) is being reduced in both equations, and when the same species is involved in both step...
by Lucian1F
Mon Mar 05, 2018 7:10 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: 15.19
Replies: 3
Views: 178

Re: 15.19

You look for two reactions where there is a difference in concentrations for just one of the reactants, then use this and the change in the rate to get the order of that reactant. Repeat this to get the orders of the others reactants. Once you have all the orders, you can pick any trial you want, pl...
by Lucian1F
Mon Mar 05, 2018 3:28 pm
Forum: Balancing Redox Reactions
Topic: Reducing power
Replies: 2
Views: 116

Re: Reducing power

Yep, both things you said are right. The standard reduction potential for Br2 is 1.07 V and for I2 it is 0.54V. So Br2 has a greater tendency to get reduced, meaning it has a lower reducing power since it is worse at reducing other species, and it has a stronger oxidizing power since it has a higher...
by Lucian1F
Fri Mar 02, 2018 9:30 pm
Forum: Zero Order Reactions
Topic: Difference between zero, first, second [ENDORSED]
Replies: 3
Views: 164

Re: Difference between zero, first, second [ENDORSED]

Let's say we have a reaction A -> B. For zero order reactants, the rate at which the reaction occurs is not affected by the concentration of that reactant. So if [A] is 1.0M in one reaction but [A] is 2.0M in another reaction, the rate at which the reaction occurs will be the same for both concentra...
by Lucian1F
Wed Feb 28, 2018 5:13 pm
Forum: General Rate Laws
Topic: 15.17 and 15.19 [ENDORSED]
Replies: 2
Views: 118

Re: 15.17 and 15.19 [ENDORSED]

Yep, it's just the sum of the individual orders
by Lucian1F
Wed Feb 28, 2018 5:11 pm
Forum: Second Order Reactions
Topic: positive slope in second ordre graph
Replies: 2
Views: 144

Re: positive slope in second ordre graph

The graph is plotting 1/concentration against time and since as time increases, the concentration of a reactant will decrease, but since the y axis is 1/concentration, the y value will increase as time goes on since the y value will increase as concentration decreases because it is in the denominator
by Lucian1F
Wed Feb 28, 2018 5:09 pm
Forum: General Rate Laws
Topic: Overall order [ENDORSED]
Replies: 6
Views: 244

Re: Overall order [ENDORSED]

We don't need to know negative or fractional orders but if you know the orders of all the reactants you should know that the overall order is just the sum of those individual orders
by Lucian1F
Tue Feb 20, 2018 9:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 14.35
Replies: 1
Views: 96

Re: 14.35

If temperature isn't stated then you can assume a reaction is at standard temperature (25 Celsius)
by Lucian1F
Tue Feb 20, 2018 9:00 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: 14.37(c)
Replies: 1
Views: 101

Re: 14.37(c)

H2 and Cl2 are on different sides of the salt bridge but they are both products. The cell reaction is 2HCl -> H2 +Cl2
by Lucian1F
Tue Feb 20, 2018 8:18 pm
Forum: Balancing Redox Reactions
Topic: 14.5 a-ox numbers
Replies: 1
Views: 92

Re: 14.5 a-ox numbers

The oxygen that is bonded to the bromine got reduced to -2
by Lucian1F
Tue Feb 20, 2018 8:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram/equation
Replies: 2
Views: 103

Re: Cell diagram/equation

If the equation is flipped then the sign of the voltage is switched too, but the reaction will be the same with reactants and products on opposite sides
by Lucian1F
Wed Feb 14, 2018 2:28 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Constant Pressure
Replies: 2
Views: 168

Re: Constant Pressure

For a constant volume, not pressure, the work is 0 so U=q=H. The example you stated says U=q at constant volume
by Lucian1F
Wed Feb 14, 2018 2:22 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: given two temperatures and 2 volumes solve for delta S
Replies: 2
Views: 156

Re: given two temperatures and 2 volumes solve for delta S

You need to add the change in entropy due to the change in volume to the change in entropy due to the change in temperature. So basically, you do two different equations and add them together. I think it is assumed that the pressure is 1 atm, so you can calculate n with PV=nRT
by Lucian1F
Mon Feb 12, 2018 6:36 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: partial pressure units
Replies: 1
Views: 86

Re: partial pressure units

Nope it doesn't matter because the ratio will be the same so Q/K will be the same regardless of units of pressure
by Lucian1F
Sun Feb 11, 2018 8:59 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Finding Temperature Where Reaction is Spontaneous
Replies: 2
Views: 109

Re: Finding Temperature Where Reaction is Spontaneous

If you find it where G=0, you can figure out exactly what the temperature needs to be greater than or less than depending on the entropy for the reaction to be spontaneous
by Lucian1F
Sat Feb 10, 2018 8:02 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.65
Replies: 1
Views: 138

Re: 8.65

Your method was totally fine, but just be careful of what the question wants you to do. It may ask for you to do the problem a specific way, but if it doesn't the way you did it was perfectly fine and will get the same result as the other way for other questions
by Lucian1F
Thu Feb 08, 2018 9:29 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Intensive Property of Standard Cell Potential
Replies: 3
Views: 147

Re: Intensive Property of Standard Cell Potential

The value of the specific heat itself is intrinsic because it will always be the same for some molecule at some phase. The specific heat does not change as mass does, the heat/energy does
by Lucian1F
Tue Feb 06, 2018 9:28 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Pressure and Volume
Replies: 3
Views: 92

Re: Pressure and Volume

For ratios the units do not matter as long as they are the same for pressure and volume. With temperature it is different since you are adding a factor of 273 to turn celsius into kelvin but for pressure and volume, converting between units is multiplication or division, so the ratio will always be ...
by Lucian1F
Tue Feb 06, 2018 9:25 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: How cold is that iced tea tho
Replies: 1
Views: 93

Re: How cold is that iced tea tho

You need to set the heat gained by the ice equal to the heat lost by the tea and dont forget to include the heat of fusion for the ice tho.
by Lucian1F
Mon Feb 05, 2018 5:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: deriving how delta G relates to work
Replies: 2
Views: 125

Re: deriving how delta G relates to work

If you remember the curve on a PV graph for a reversible pathway, it curves downward and the area under this curve is the work. The curve looks like this: https://upload.wikimedia.org/wikipedia/ ... m_work.png
by Lucian1F
Mon Feb 05, 2018 5:13 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible Reaction Total Entropy
Replies: 1
Views: 95

Re: Reversible Reaction Total Entropy

The heat of the system doesnt change since the surroundings keep it stable and the heat of the surroundings doesnt change because it is a reservoir
by Lucian1F
Sun Feb 04, 2018 10:30 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Pulley and Vacuum
Replies: 2
Views: 141

Re: Pulley and Vacuum

If you imagine a piston thats controlled by a weight and that weight is slowly removed, then the system will slowly expand and do work
by Lucian1F
Sat Feb 03, 2018 4:56 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: 9.65
Replies: 6
Views: 230

9.65

Can someone help me figure out how to do 9.65? It asks "Which of the following compounds become less stable with respect to the elements as the temperature is raised: a. PCl5 (g) b. HCN (g) c. NO (g) d. SO2 (g)"
by Lucian1F
Fri Feb 02, 2018 9:47 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.35 [ENDORSED]
Replies: 5
Views: 182

Re: 9.35 [ENDORSED]

I believe it's saying that there are 1 mol of atoms in a, b, and c, but in b and c those atoms bind together to form diatomic molecules so then there are .5 moles of particles for b and c so a has the most particles.
by Lucian1F
Thu Feb 01, 2018 3:05 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Question 8.13
Replies: 3
Views: 107

Re: Question 8.13

If it was not irreversibly, some of the equations we use would not work because irreversible reactions occur at constant temperature but if it was not irreversible there would be a change in temperature
by Lucian1F
Thu Feb 01, 2018 3:03 pm
Forum: Calculating Work of Expansion
Topic: Expansion
Replies: 3
Views: 145

Re: Expansion

If the volume is expanding then the system is doing work
by Lucian1F
Mon Jan 29, 2018 4:38 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: formula for standard entropy
Replies: 5
Views: 231

Re: formula for standard entropy

Yes they are the same just with S replacing H
by Lucian1F
Sat Jan 27, 2018 1:52 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Spontaneous Reactions [ENDORSED]
Replies: 2
Views: 59

Re: Spontaneous Reactions [ENDORSED]

We haven't gone over how to calculate whether or not a reaction is spontaneous. The examples Dr. Lavelle gave in lecture were obvious examples like how gas would spontaneously expand in its container and it would never spontaneously bunch up in its container, but for more ambiguous processes there a...
by Lucian1F
Sat Jan 27, 2018 1:49 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible isothermal expansion
Replies: 4
Views: 112

Re: Reversible isothermal expansion

I highly doubt we will need to show the derivations. Dr. Lavelle just showed us the derivations so we understand where the formulas came from so we wouldn't blindly memorize these formulas without knowing where they came from
by Lucian1F
Mon Jan 22, 2018 9:11 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Textbook example 8.6
Replies: 1
Views: 101

Re: Textbook example 8.6

Since the system is at a constant volume, the work is 0, so the change in internal energy is equal to heat, so delta U = q.
by Lucian1F
Mon Jan 22, 2018 9:08 pm
Forum: Phase Changes & Related Calculations
Topic: Problem 8.71
Replies: 1
Views: 109

Re: Problem 8.71

We didn't cover the concepts of this question in class so you don't need to know how to do it. 71 isn't listed as one of the homework problems to choose from on the syllabus. If you want to figure it out for your own sake no one's stopping you, just read the section that covers it in the book!
by Lucian1F
Mon Jan 22, 2018 9:06 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.53
Replies: 1
Views: 96

Re: 8.53

The question gives you heat capacity, not molar heat capacity. When you are given molar heat capacity, you need to multiply by the number of moles so the units cancel to leave units of energy, but with heat capacity all you need to do is multiply it by the change in temperature to get units of energ...
by Lucian1F
Mon Jan 22, 2018 9:01 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Positional (Residua) Entropy
Replies: 1
Views: 105

Re: Positional (Residua) Entropy

Positional entropy is related to how many positions an object, like an atom, can be in.
by Lucian1F
Thu Jan 18, 2018 9:36 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Reaction Enthalpy v. Enthalpy of Formation
Replies: 4
Views: 102

Re: Reaction Enthalpy v. Enthalpy of Formation

It will probably be stated in the question and only one of these will probably be given to you to solve a problem. If both are given, you may need to combine the two methods or choose to do either method if the problem can be solved like that
by Lucian1F
Thu Jan 18, 2018 9:29 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 8.41
Replies: 3
Views: 175

Re: 8.41

The temperature of the water is higher than 0 degrees Celsius so you need to take the amount of energy it takes to melt the given amount of ice first and consider that in your calculations.
by Lucian1F
Tue Jan 16, 2018 9:36 pm
Forum: Administrative Questions and Class Announcements
Topic: Acids and Bases
Replies: 3
Views: 160

Re: Acids and Bases

It may not be needed for anything in 14B but for 14BL there are acid/base labs
by Lucian1F
Tue Jan 16, 2018 9:34 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Problem 8.75 (b)
Replies: 3
Views: 121

Re: Problem 8.75 (b)

Definitely draw out the lewis structures! It will help tremendously and if you dont it is very likely you will miss at least one bond.
by Lucian1F
Sat Jan 13, 2018 2:00 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Formation
Replies: 3
Views: 118

Re: Formation

Remember that the periodic table is split into metals and nonmetals and that metals are typically solids at standard conditions and nonmetals are typically gases. Also, remember that mercury and bromine are liquids at standard conditions!
by Lucian1F
Tue Jan 09, 2018 8:09 pm
Forum: Phase Changes & Related Calculations
Topic: Endo and Exothermic Ways to Remember
Replies: 28
Views: 2984

Re: Endo and Exothermic Ways to Remember

For me I think about how they sound. The "en" in endothermic sounds like in and the "ex" in exothermic reminds me of exit.
by Lucian1F
Tue Jan 09, 2018 8:06 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes [ENDORSED]
Replies: 3
Views: 195

Re: Phase Changes [ENDORSED]

It may also be helpful to know that fusion is another term that is the same phase change as melting (solid to liquid)
by Lucian1F
Tue Dec 05, 2017 6:00 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Strong Acids/Bases
Replies: 3
Views: 196

Re: Strong Acids/Bases

Their equilibrium constants are basically infinity since there are hardly any reactants, so no
by Lucian1F
Mon Dec 04, 2017 8:34 pm
Forum: Lewis Acids & Bases
Topic: 12.119
Replies: 1
Views: 136

Re: 12.119

When the hydrogen is removed from boric acid, the oxygens will experience a more negative charge. Boron has a low electronegativity, so it cannot help stabilize the anion
by Lucian1F
Mon Dec 04, 2017 8:30 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: F and Cl in acids
Replies: 2
Views: 166

Re: F and Cl in acids

The strengths for these acids depend on different factors. Since the H-F bond is shorter than the H-Cl bond, HF is less likely to dissociate than HCl, so it is a weaker acid. However, in the case of C2O2HF3 and C2O2HCl3, the strength of the acid depends on electronegativity. Since F is more electron...
by Lucian1F
Mon Nov 27, 2017 9:11 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Chemical Equilibrium Part 2 Post-Module #19 & 27
Replies: 2
Views: 175

Re: Chemical Equilibrium Part 2 Post-Module #19 & 27

Did you make sure to omit the solid molecule from the calculations? Solids are not included in equilibrium constant equations
by Lucian1F
Mon Nov 27, 2017 8:58 pm
Forum: Hybridization
Topic: Lone Pairs in Hybridization
Replies: 4
Views: 289

Re: Lone Pairs in Hybridization

It solely relies on the amount of areas of electron density, including the lone pairs
by Lucian1F
Mon Nov 27, 2017 8:57 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to use ICE box
Replies: 2
Views: 309

Re: When to use ICE box

The ICE box is used when the problem involves using both equilibrium and initial concentrations of the products and reactants
by Lucian1F
Mon Nov 27, 2017 8:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.1 Homework
Replies: 2
Views: 143

Re: 11.1 Homework

The equilibrium constant does not change with a change in pressure
by Lucian1F
Sun Nov 26, 2017 3:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: chemical equilibrium part 2 module #12
Replies: 1
Views: 96

Re: chemical equilibrium part 2 module #12

The chemical equilibrium constant Kc=[Br]^2/[Br2]. So you take the square root of the product of Kc and Br2 to get the answer, which is C
by Lucian1F
Tue Nov 21, 2017 1:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous and Gaseous Phases
Replies: 3
Views: 170

Re: Aqueous and Gaseous Phases

If there are both gases and aqueous molecules in a reaction then you will need to use PV=nRT to find the concentration of the gases, then find Kc.
by Lucian1F
Mon Nov 20, 2017 10:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Homework question 17.33
Replies: 4
Views: 221

Re: Homework question 17.33

You need to take into account the molecular shapes. It needs to be possible for multiple electron pairs to bind to the transition metal with the molecular shape of the ligand
by Lucian1F
Mon Nov 20, 2017 10:00 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Part D; Question 17.33
Replies: 1
Views: 152

Re: Part D; Question 17.33

The molecule's shape matters in this case. It will be trigonal planar around each carbon, so only two oxygen atoms will be able to bond to the metal at a time.
by Lucian1F
Thu Nov 16, 2017 10:28 pm
Forum: Hybridization
Topic: Double sigma v. pi bonds
Replies: 4
Views: 180

Re: Double sigma v. pi bonds

There is no such thing as a double sigma bond. A double bond consists of one sigma bond and one pi bond. A triple bond consists of one sigma bond and two pi bonds.
by Lucian1F
Tue Nov 14, 2017 11:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2 Lone Pairs and 2 Bonding Pairs vs 1 Lone Pair and 2 Bonding Pairs
Replies: 2
Views: 142

Re: 2 Lone Pairs and 2 Bonding Pairs vs 1 Lone Pair and 2 Bonding Pairs

The bond angle for the molecule with 2 bonds and 1 lone pair would be greater than the bond angle for the molecule with 2 bonds and 2 lone pairs since more lone pairs means more repulsion
by Lucian1F
Tue Nov 14, 2017 8:30 pm
Forum: Hybridization
Topic: Superscript
Replies: 3
Views: 234

Re: Superscript

The superscript is showing how many p-orbitals have been hybridized. So in sp, one p-orbital is hybridized, sp^2 has two hybridized, and sp^3 has three hybridized.
by Lucian1F
Sat Nov 11, 2017 4:25 pm
Forum: Resonance Structures
Topic: Determining Best Lewis Structure [ENDORSED]
Replies: 2
Views: 224

Re: Determining Best Lewis Structure [ENDORSED]

In the best lewis structure, the formal charge for every atom in the molecule, not just the central atom, will be as close to 0 as possible
by Lucian1F
Sat Nov 11, 2017 4:23 pm
Forum: Octet Exceptions
Topic: Expanding an Octet [ENDORSED]
Replies: 2
Views: 204

Re: Expanding an Octet [ENDORSED]

I think what you're getting at is if there is a negative formal charge, then it should go on the most electronegative atom. This happens since the more electronegative atom will draw in electrons stronger, so it would be more stable for the more electronegative atom to have more electrons resulting ...
by Lucian1F
Sat Nov 11, 2017 4:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: See-saw [ENDORSED]
Replies: 2
Views: 129

See-saw [ENDORSED]

For the See-saw vsepr shape is the bond angle between the two equatorial atoms 120 or less than 120?
by Lucian1F
Thu Nov 09, 2017 4:05 pm
Forum: Lewis Structures
Topic: double bonds in NO3-
Replies: 2
Views: 224

Re: double bonds in NO3-

If there were 3 double bonds then nitrogen would have more than an octet (it would have 12 electrons in its valence shell) but nitrogen is only in the second period so it cannot have more than 8 valence electrons. Also, this would make the formal charges of nitrogen and oxygen much farther from 0, w...
by Lucian1F
Wed Nov 08, 2017 11:00 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: delta v
Replies: 4
Views: 269

Re: delta v

Yes, this is correct
by Lucian1F
Wed Nov 08, 2017 10:05 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Topics
Replies: 1
Views: 158

Midterm Topics

Will we need to know what the Lyman and Balmer series are for the midterm? Thanks!
by Lucian1F
Wed Nov 08, 2017 10:00 pm
Forum: Lewis Structures
Topic: HW 3.103
Replies: 1
Views: 137

Re: HW 3.103

For molecules with many carbon atoms, you probably need to make a carbon ring. In this case, make a carbon ring, then put oxygens on carbons opposite from each other, and put the one hydrogen on the other carbons. The carbon-oxygen bonds will be double bonds, and the bonds between carbons that are b...
by Lucian1F
Wed Nov 08, 2017 9:55 pm
Forum: Ionic & Covalent Bonds
Topic: Polar vs. Non-polar
Replies: 7
Views: 359

Re: Polar vs. Non-polar

We don't need to know how to calculate a dipole moment. We only need to know what it is and determine if there is one
by Lucian1F
Mon Nov 06, 2017 10:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Xenon Tetrafluoride?
Replies: 4
Views: 412

Re: Xenon Tetrafluoride?

This molecule, and all molecules with a square planar shape are rather rare. You don't need to know the element as long as you know how to draw the lewis structure. Once you have the lewis structure down, you can see the regions of electron density and see if they are lone pairs or bonds, then this ...
by Lucian1F
Thu Nov 02, 2017 8:54 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Increasing Covalent Character of Silver Halides
Replies: 1
Views: 595

Re: Increasing Covalent Character of Silver Halides

As you go down the halogen group, they decrease in ionization energy and electron affinity, so they decrease in electronegativity as well. Therefore, the difference in electronegativity between silver and the halide will decrease as you go down the halogen group. So, since an large difference is cha...
by Lucian1F
Thu Nov 02, 2017 8:49 pm
Forum: Trends in The Periodic Table
Topic: Carbon vs. Nitrogen Ionization Trend
Replies: 3
Views: 205

Re: Carbon vs. Nitrogen Ionization Trend

The trends are just general trends. In general, the ionization energies of elements will decrease down the periodic table and increase across. However, there are multiple exceptions. These trends are just in general, they do not apply to every single case. We didn't go over specific exceptions to th...
by Lucian1F
Thu Nov 02, 2017 8:47 pm
Forum: Bond Lengths & Energies
Topic: Ionic Character and Covalent Character
Replies: 2
Views: 232

Re: Ionic Character and Covalent Character

I think we will be given electronegativity values of each element, then using these values, we find the differences in electronegativities between the two elements bonded. If the difference is greater than 2, the bond is ionic. If the difference is less than 1.5, it is covalent. There are rough esti...
by Lucian1F
Tue Oct 31, 2017 2:02 pm
Forum: Trends in The Periodic Table
Topic: Chapter 2, Question 85
Replies: 1
Views: 180

Re: Chapter 2, Question 85

When we were doing those graph/chart things with quantum mechanics and exciting electrons to higher energy levels, as we increased the energy level, the differences in energy between them kept decreasing. So as you get higher and higher, the differences between energy levels and subshells become les...
by Lucian1F
Tue Oct 31, 2017 1:57 pm
Forum: Octet Exceptions
Topic: F orbitals
Replies: 4
Views: 266

Re: F orbitals

Yes, any atom that has a principle quantum number of n=4 or greater can have electrons in the f subshell
by Lucian1F
Tue Oct 31, 2017 1:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration for Bi3+
Replies: 1
Views: 365

Re: Electron Configuration for Bi3+

For the d sublevel, you need to subtract one from the principle quantum number, so it would be 5d. For the f sublevel, you need to subtract two form the principle quantum number, so it would be 4f.
by Lucian1F
Thu Oct 26, 2017 9:42 pm
Forum: Trends in The Periodic Table
Topic: Periodic Trends
Replies: 2
Views: 173

Re: Periodic Trends

The second ionization energy is the energy required to take the next electron after an electron is already taken from an atom. They have numerical values, but I don't think those can be determined with anything we've learned. To determine whether it is higher than lower or something, treat it like y...
by Lucian1F
Thu Oct 26, 2017 9:32 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs. Covalent Bonds [ENDORSED]
Replies: 8
Views: 435

Re: Ionic vs. Covalent Bonds [ENDORSED]

A covalent bond is between nonpolar, or atoms with little charge. An ion is between two ions which have very high charge in comparison. Elements want a full octet, or achieve the noble gas configuration, because this configuration is the most stable. What holds the two atoms together in an ionic bon...
by Lucian1F
Tue Oct 24, 2017 9:39 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: No f- orbital questions? [ENDORSED]
Replies: 4
Views: 291

Re: No f- orbital questions? [ENDORSED]

I'm pretty sure all you have to know is that energy levels n=4 and after have f-orbitals, the f-orbitals are l=3, and ml= -3,-2,-1, 0, 1, 2, 3.
by Lucian1F
Tue Oct 24, 2017 9:33 pm
Forum: Photoelectric Effect
Topic: Work function v. Ionization Energy
Replies: 2
Views: 655

Re: Work function v. Ionization Energy

The work function is typically related to the photoelectric effect where photons hit a solid metal and if the energy of a photon is higher than the work function, then the electrons are ejected from the metal. For ionization energy, the energy is related to the energy required to remove an electron ...
by Lucian1F
Mon Oct 16, 2017 11:09 pm
Forum: Properties of Light
Topic: emission and absorption spectrum
Replies: 3
Views: 225

Re: emission and absorption spectrum

The values of the lines will be the same since the energy levels for each element are constant. The lines only change as you change elements. The difference is in what is measured. If the wavelengths/frequencies of light that are being released by the atom are measured, it results in an emission spe...
by Lucian1F
Mon Oct 16, 2017 11:06 pm
Forum: DeBroglie Equation
Topic: Homework Problems
Replies: 3
Views: 207

Re: Homework Problems

If you go to the website and you go to lecture outlines, it can be found in outline 2. It is: Read: Ch 1 Do Problems: 3, 5, 7, 9, 11, 13, 15, 21, 23, 25, 27, 33, 37, 39, 41, 43, 55, 57, 59, 65, 67, 69 Read: Ch 2 (Omit Table 2.1) Do Problems: 1, 13, 17, 19, 21, 23, 25, 27, 29, 31, 33, 37, 39, 41, 43,...
by Lucian1F
Mon Oct 16, 2017 7:26 pm
Forum: Properties of Electrons
Topic: Hydrogen Series
Replies: 4
Views: 269

Re: Hydrogen Series

I highly doubt that we need to memorize those series since they aren't in the textbook and I believe they haven't been covered in class either.
by Lucian1F
Mon Oct 16, 2017 7:24 pm
Forum: Properties of Electrons
Topic: Electromagnetic Spectrum
Replies: 2
Views: 191

Re: Electromagnetic Spectrum

You don't need to memorize the exact values for each type of electromagnetic radiation. However, we do need to know that visible light is around 400-700 nanometers, and having rough estimates of the other electromagnetic waves would probably be a good idea.
by Lucian1F
Sat Oct 14, 2017 10:29 pm
Forum: DeBroglie Equation
Topic: Post-Module Assessment #35 [ENDORSED]
Replies: 2
Views: 241

Post-Module Assessment #35 [ENDORSED]

Calculate the wavelength of a 275 kg single-seat electric car traveling at a speed of 125 km.hr-1. Do electric cars have wavelike properties? A. λ = 6.94 x 10-38 m , Yes B. λ = 6.94 x 10-38 m , No C. λ = 1.93 x 10-38 m , Yes D. λ = 1.93 x 10-38 m , No The correct answer is B. The wavelength is so sm...
by Lucian1F
Thu Oct 12, 2017 8:24 pm
Forum: Properties of Light
Topic: Figure 1.9
Replies: 4
Views: 255

Re: Figure 1.9

It is not required to memorize the exact values for each type of electromagnetic radiation, but you should know that visible light is around 400-700 nanometers. It would probably be a good idea to have some approximation of each type memorized, but Dr. Lavelle said that we did not need to memorize t...
by Lucian1F
Mon Oct 09, 2017 10:23 pm
Forum: Properties of Light
Topic: Chapter 1 Problem 7b
Replies: 3
Views: 162

Re: Chapter 1 Problem 7b

Alright, thank you!
by Lucian1F
Mon Oct 09, 2017 8:42 pm
Forum: Properties of Light
Topic: Chapter 1 Problem 7b
Replies: 3
Views: 162

Chapter 1 Problem 7b

"When an electron beam strikes a block of copper, x-rays with a frequency of 2.0 x 10^18 Hz are emitted. What is the wavelength (in picometers) of these x-rays?" I got an answer of 150 pm but the back of the book says 150 nm. I'm pretty sure this is just a typo, especially since the questi...
by Lucian1F
Thu Oct 05, 2017 8:15 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity and Dilution [ENDORSED]
Replies: 7
Views: 943

Re: Molarity and Dilution [ENDORSED]

In this case it is possible to use the MiVi = MfVf equation. Mi = 9.85M and Vi = .075L and Vf = .125L. So, if you multiply Mi by Vi then divide this product by Vf you end up with 5.91M. Another way you could solve this problem is simply converting the grams into moles, which would be .739 mol, then ...
by Lucian1F
Thu Oct 05, 2017 8:08 pm
Forum: Molarity, Solutions, Dilutions
Topic: G. 21
Replies: 3
Views: 331

Re: G. 21

You first need to calculate the amount of moles for each compound by dividing the given masses by the molar masses resulting in .00671 mol KCl, .00453 mol K2S, and .00236 mol K3PO4. Therefore, there are .00671 mol K in KCl, .00906 mol K in K2S, and .00472 mol K in K3PO4 for .0205 mol K total and .00...
by Lucian1F
Wed Oct 04, 2017 9:12 pm
Forum: SI Units, Unit Conversions
Topic: Sig Figs
Replies: 12
Views: 741

Re: Sig Figs

There are 2 sig figs in 460. In this case, the 4 and the 6 are significant. All nonzero numbers are significant, so in 123.45, there are five sig figs. Also, all zeros in front of a number without a decimal point in front of them are insignificant, so in 00460, there would still be just two sig figs...

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