## Search found 51 matches

Mon Dec 02, 2019 2:55 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Pka
Replies: 2
Views: 56

### Re: Pka

A large Ka value indicates a strong acid because it means the acid is largely dissociated into its ions. A small Ka value means little of the acid dissociates, so you have a weak acid. The pKa gives the same information, just in a different way. The smaller the value of pKa, the stronger the acid.
Mon Dec 02, 2019 2:52 pm
Forum: Identifying Acidic & Basic Salts
Topic: Cations groups 1 and 2
Replies: 2
Views: 41

### Re: Cations groups 1 and 2

Because they are weak lewis acids and do not generate H3O+
Mon Dec 02, 2019 2:49 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: H-F, H-Cl, H-Br, and H-I
Replies: 3
Views: 64

### Re: H-F, H-Cl, H-Br, and H-I

H-F was the weakest acid because it has the shortest, strongest bond. The acids get stronger down that list (the longer the bond gets.)
Mon Dec 02, 2019 2:41 pm
Forum: Properties of Light
Topic: Average wavelength of an atom
Replies: 2
Views: 127

### Re: Average wavelength of an atom

wavelength= h/ mv ; plug in mass for m and speed for v
Mon Dec 02, 2019 2:35 pm
Forum: Einstein Equation
Topic: Work Function
Replies: 1
Views: 147

### Re: Work Function

If you mean given the value of the work function, you would use the equation hf=work function+ Ek. Ek= 1/2mv^2. and solve for f after plugging in the given values.
Mon Dec 02, 2019 2:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 8
Views: 319

### Re: Electron Configuration

3d, 4s
Mon Dec 02, 2019 2:27 pm
Forum: Properties of Light
Topic: Visible Light Spectrum
Replies: 3
Views: 117

### Re: Visible Light Spectrum

I think we should at least know that the visible light spectrum is 400-700 nm.
Mon Nov 25, 2019 4:34 pm
Forum: Naming
Topic: naming complexes
Replies: 2
Views: 47

### Re: naming complexes

If the complex ion is an anion, the name of the metal ends with -ate. However, instead of 'ironate' the name that should be used is ferrate instead.
Mon Nov 25, 2019 4:31 pm
Forum: Air Pollution & Acid Rain
Topic: Clean Coal vs Dirty Coal?
Replies: 16
Views: 207

### Re: Clean Coal vs Dirty Coal?

I think he explained it as clean coal having lower sulfur content, but higher carbon content and vice versa for dirty coal. The clean coal produces less SO2.
Mon Nov 25, 2019 4:28 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 3
Views: 71

### Coordination Number

What is the coordination number/ what does it indicate?
Mon Nov 25, 2019 4:27 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming
Replies: 3
Views: 65

### Naming

Can someone explain the steps in naming in a clearer way then how he did it in class? I'm just confused as to what you name first and which has the roman numeral, etc.
Mon Nov 25, 2019 4:25 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition metals
Replies: 4
Views: 95

### Re: Transition metals

If it is written in the coordination complex and if h2o is present it then yes, the transition metal will bond.
Mon Nov 18, 2019 2:32 pm
Forum: Sigma & Pi Bonds
Topic: Sigma and Pi Bonds
Replies: 4
Views: 90

### Re: Sigma and Pi Bonds

Yes, for what we are learning right now, this will always hold true.
Mon Nov 18, 2019 2:31 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Condition for pi bond
Replies: 4
Views: 67

### Re: Condition for pi bond

If you have a pi bond, there will always also be a sigma bond.
Mon Nov 18, 2019 2:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bonds in VSEPR
Replies: 11
Views: 127

### Re: Bonds in VSEPR

You don't need to take it into account when determining its shape, they are counted for as one.
Mon Nov 18, 2019 2:26 pm
Forum: Dipole Moments
Topic: Dipole moments
Replies: 4
Views: 66

### Re: Dipole moments

Draw it with the arrow pointing towards the negative rather than the positive.
Mon Nov 18, 2019 2:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Pi Bond vs Sigma
Replies: 6
Views: 81

### Pi Bond vs Sigma

Are one of these bonds stronger than the other? Pi bond vs Sigma? If so, why?
Wed Nov 13, 2019 4:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR model angles
Replies: 7
Views: 67

### VSEPR model angles

Do we need to know the specific angles of each shape?
Wed Nov 13, 2019 4:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Tetrahedral VSPER model
Replies: 7
Views: 114

### Re: Tetrahedral VSPER model

I think this shape is always regarding the central atom with 4 surrounding bonds.
Wed Nov 13, 2019 4:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape
Replies: 8
Views: 89

### Re: Shape

Yes, based on the lecture alone today, lone pairs don't have an effect on the shape. We haven't looked at lone pair electrons with the central atom yet.
Wed Nov 13, 2019 4:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Will we need to know these VSEPR shapes as well?
Replies: 10
Views: 140

### Re: Will we need to know these VSEPR shapes as well?

I think unless he goes over them on by the end of the chapter, or if it shows up in the homework he assigned, we don't need to know them.
Wed Nov 13, 2019 4:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VESPR Model of H2O
Replies: 12
Views: 232

### Re: VESPR Model of H2O

I think we will learn more about its shape in particular (bent) on Friday or next week.
Thu Nov 07, 2019 1:23 pm
Forum: Trends in The Periodic Table
Topic: Polarizability
Replies: 4
Views: 61

### Polarizability

Can someone explain more specifically how you can tell whether something has more polarizability compared to something else? Like how would you arrange the anions :Cl-, Br-, N3-, and O2- in order of increasing polarizability?
Thu Nov 07, 2019 1:20 pm
Forum: Ionic & Covalent Bonds
Topic: Solubility
Replies: 3
Views: 56

### Re: Solubility

Yes, covalent character makes it less soluble. So, if it is more ionic, then it is more soluble.
Thu Nov 07, 2019 1:19 pm
Forum: Trends in The Periodic Table
Topic: Ionization energies
Replies: 3
Views: 63

### Ionization energies

Can someone explain why the ionization energy of O is lower than N if it comes after Nitrogen on the periodic table.
Thu Nov 07, 2019 1:17 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Shortcut for Formal Charge
Replies: 19
Views: 551

### Re: Shortcut for Formal Charge

What I do to make it faster is subtract the # of electrons for the element in the structure (counting a bond as one) from the valence electrons of that element.
Thu Nov 07, 2019 1:16 pm
Forum: Lewis Structures
Topic: Lewis structure
Replies: 5
Views: 60

### Lewis structure

For the Lewis structure of PO4 3-, I know it has one double bond and the rest are single, but why can't all four be double bonds with all of the O having 0 formal charge and the P having a 3- charge?
Fri Nov 01, 2019 4:17 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charges
Replies: 4
Views: 68

### Formal Charges

Can anyone explain how to use formal charges when drawing the resonance structure?
Fri Nov 01, 2019 4:12 pm
Forum: Trends in The Periodic Table
Topic: Studying techniques
Replies: 3
Views: 57

### Re: Studying techniques

I think it helps just memorizing that electronegativity increases going up from right. From there, you can basically derive the other trends (electron affinity, ionization energy, atomic radius, etc.) since they are all related.
Fri Nov 01, 2019 4:08 pm
Forum: Trends in The Periodic Table
Topic: electron affinity and electronegativity
Replies: 2
Views: 41

### Re: electron affinity and electronegativity

Electron affinity measures the energy released when an electron adds to a gaseous atom while Electronegativity, is the tendency of an atom to attract toward itself the electron density in a shared bond. EA is measured in Joules per mole.
Fri Nov 01, 2019 4:05 pm
Forum: Trends in The Periodic Table
Topic: Exceptions
Replies: 3
Views: 68

### Re: Exceptions

I think some exceptions worth remembering are : Boron has a lower ionization energy than Beryllium and Oxygen has a lower ionization energy than Nitrogen (which contradicts the general trend). Nitrogen's electron affinity is lower than carbon's and that Neon's is lower than fluorine's and lithiums.
Fri Nov 01, 2019 4:01 pm
Forum: Resonance Structures
Topic: Resonance Hybrid
Replies: 2
Views: 43

### Resonance Hybrid

On one of the homework problems it asks to draw the lewis structures that contribute to the resonance hybrid of HClO4 and HClO3, in my discussion my TA drew all 3 possible ways for the double bond to go, is this always necessary?
Mon Oct 21, 2019 7:05 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 81

### Re: Schrodinger Equation

That symbol represents the height of a wave at position x,y,z. It is used in the equation as wave function (orbital) representing e-.
Mon Oct 21, 2019 7:02 pm
Forum: Balancing Chemical Reactions
Topic: Balancing equations.
Replies: 35
Views: 591

### Re: Balancing equations.

I would say a good way to balance an equation is to begin with the least occurring element first and then to work your way up from there. I would go back and forth and write down each step of the way one by one and then in the end double check to make sure it is the same on the left and right of the...
Mon Oct 21, 2019 6:59 pm
Forum: Trends in The Periodic Table
Replies: 3
Views: 40

What is the difference between the atomic, covalent and ionic radii? I know they show the same trends, but what is the difference between them?
Mon Oct 21, 2019 6:57 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 6
Views: 145

### Electron Affinity

Can anyone explain what electron affinity is and more specifically, how it pertains to trends in the periodic table?
Mon Oct 21, 2019 6:55 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration Specifics
Replies: 3
Views: 49

### Electron Configuration Specifics

In class, Lavelle did the electron configuration for Nitrogen and used the subscripts x1, y1, and z1 : 1s2 2s2 2px1 2py1 2pz1 ; does anyone why he did this and if we have to do this each time we do an electron configuration?
Mon Oct 14, 2019 7:02 pm
Forum: Properties of Electrons
Topic: Question from Heisenberg's Uncertainty Principle post test
Replies: 2
Views: 84

### Re: Question from Heisenberg's Uncertainty Principle post test

1% of 0.05 nm is 0.01 x 0.05nm= 5e-4m
Mon Oct 14, 2019 6:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbital equation
Replies: 3
Views: 46

### Re: Orbital equation

He defined it as 2 lobes on either side of the nucleus; at the nucleus there is a nodal plane with 0 probability of electron density; px, py, pz
Mon Oct 14, 2019 6:56 pm
Forum: Properties of Light
Topic: Matching Wavelength to Type of EM Radiation
Replies: 2
Views: 33

### Re: Matching Wavelength to Type of EM Radiation

We only have to know the general range (700 nm to 400 nm).
Mon Oct 14, 2019 6:50 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Indeterminacy Equation
Replies: 3
Views: 63

### Re: Indeterminacy Equation

Yes, it would be 10 because it could fall into the range 1-10.
Mon Oct 14, 2019 6:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Positive and Negative signs?
Replies: 5
Views: 75

### Re: Positive and Negative signs?

A negative sign in front of energy would indicate an emission of energy (the electron moves from a higher to a lower energy level. Positive is just the vice-versa of this (a lower to a higher energy level).
Wed Oct 09, 2019 8:20 pm
Forum: Properties of Light
Topic: HW Question #1A.15
Replies: 6
Views: 66

### Re: HW Question #1A.15

The final energy level is the one where electron ends up at. The initial is the level at which it starts. For example, going n=2 to n=1; the electron starts at n=2 so this is the initial, it ends up at n=1 so this is the final.
Wed Oct 09, 2019 8:17 pm
Forum: Properties of Light
Topic: Constants in the Quantum World
Replies: 6
Views: 83

### Re: Constants in the Quantum World

h= 6.626 x 10^-34 Js and R= 3.29 x 10^15 Hz are the only other ones I can think of.
Wed Oct 09, 2019 8:13 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Typical wavelength for spectrum
Replies: 2
Views: 64

### Re: Typical wavelength for spectrum

UV light simply has a short enough wave length along with enough high energy that is able to discharge the electrons.
Wed Oct 09, 2019 8:08 pm
Forum: Significant Figures
Topic: %Mass Composition
Replies: 12
Views: 328

### Re: %Mass Composition

It depends on the problem and the lowest number of sig figs in the original problem. Usually, it is around 4 to 5 sig figs.
Wed Oct 09, 2019 8:04 pm
Forum: Photoelectric Effect
Topic: Energy of Photon = Work Function
Replies: 4
Views: 63

### Re: Energy of Photon = Work Function

If they are equal (the energy of the photon and the work function), then electrons are not emitted even for high intensity light.
Wed Oct 02, 2019 3:00 pm
Forum: Molarity, Solutions, Dilutions
Topic: Please clarify what M means
Replies: 5
Views: 93

### Re: Please clarify what M means

The capital M in this problem means Molarity (mols/L).
Wed Oct 02, 2019 2:58 pm
Forum: Empirical & Molecular Formulas
Topic: Writing Molecular Formulas with charges [ENDORSED]
Replies: 4
Views: 159

### Re: Writing Molecular Formulas with charges[ENDORSED]

Knowing the charges helps to know how many of each you need. Since sulfate is 2- and the charge of Mg is 2+, you only need one of each: MgSO4.
Mon Sep 30, 2019 8:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Will there be lecture on Nov. 27?
Replies: 3
Views: 114

### Re: Will there be lecture on Nov. 27?

We only get Thursday and friday off that week, so there should be a lecture that day.
Mon Sep 30, 2019 8:05 pm
Forum: Empirical & Molecular Formulas
Topic: Homework Problem E.9c
Replies: 5
Views: 89

### Re: Homework Problem E.9c

The problem states that it is magnesium sulfate heptahydrate. Hepta= 7, so there are 7 molecules of H20. Therefore you must multiply by 7 in part c.