Search found 69 matches

by 505095972
Sat Mar 09, 2019 1:49 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

Q: What is the dullest element?
A: Bohrium
by 505095972
Sat Mar 09, 2019 1:48 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

Q: What do chemists call a benzene ring with iron atoms replacing the carbon atoms?
A: A ferrous wheel!
by 505095972
Sat Mar 09, 2019 1:46 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: integrated rate law
Replies: 2
Views: 19

Re: integrated rate law

The rate laws only use the reactants because they are based on the initial rate of the reaction which is when no product has been created, or if it has it is so little that it is negligible. Therefore, you only need to account for the reactants in the equation.
by 505095972
Sun Mar 03, 2019 3:09 pm
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 14863

Re: Chemistry News

https://cen.acs.org/physical-chemistry/ ... eb/2018/06


Geochemistry! Cool article about chemistry in nature!
by 505095972
Sun Mar 03, 2019 3:06 pm
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 14863

Re: Chemistry News

https://www.sciencedaily.com/releases/2 ... 093626.htm

I thought this article was an interesting mix of chemistry and biology! Wanted to share!
by 505095972
Sun Mar 03, 2019 3:00 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Setting up redox equation for Nernst
Replies: 2
Views: 38

Re: Setting up redox equation for Nernst

Can you use the standard cell potentials to determine which way would be spontaneous and then use that to find which is the cathode and which is the anode?
by 505095972
Sun Mar 03, 2019 2:58 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Corrosion and Ion Selective Electrodes
Replies: 4
Views: 45

Corrosion and Ion Selective Electrodes

The book describes corrosion and ion selective electrodes/glass electrodes In a lot of detail that wasn’t talked about in class. Should we try to understand this in the same detail as in the book or is what we learned in class okay?
by 505095972
Sun Mar 03, 2019 2:55 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: standard cell potential negative and positive
Replies: 2
Views: 28

Re: standard cell potential negative and positive

A positive cell potential means that reaction is spontaneous, while a negative one means it is non spontaneous.
by 505095972
Tue Feb 26, 2019 11:43 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: HW Q
Replies: 1
Views: 35

Re: HW Q

That seems like a typo. The H+ shouldn't just disappear.
by 505095972
Tue Feb 26, 2019 11:42 am
Forum: Balancing Redox Reactions
Topic: 7th Edit 6L9
Replies: 1
Views: 29

Re: 7th Edit 6L9

In the table in the appendix, you can look at the E of each. You then use those numbers to determine which one is the cathode and which is the electrode in order for E cell to be positive. This then tells you which one is reduced (whichever one is the cathode) and which one is oxidized (whichever on...
by 505095972
Tue Feb 26, 2019 11:39 am
Forum: Balancing Redox Reactions
Topic: Solution to balancing this redox reaction
Replies: 1
Views: 31

Re: Solution to balancing this redox reaction

It looks right to me!
by 505095972
Tue Feb 26, 2019 11:38 am
Forum: Balancing Redox Reactions
Topic: 6L.3
Replies: 1
Views: 27

Re: 6L.3

Carbon isn't included because it is being used as an electrode but does not effect the redox reaction.
by 505095972
Sun Feb 17, 2019 9:49 pm
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 14863

Re: Chemistry News

I thought this was interesting and shows the interdisciplinary nature of STEM fields!

https://engineering.nyu.edu/news/nyu-re ... duce-waste
by 505095972
Sun Feb 17, 2019 9:38 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

What did the cashier say to Gibbs when he bought an energy drink?

"Don't worry about it. It's free.”
by 505095972
Sun Feb 17, 2019 9:31 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy
Replies: 7
Views: 71

Re: Gibbs Free Energy

Gibbs free energy is the maximum potential amount of reversible work that can be performed on a thermodynamic system. So a change in this means more or less work can be done on the system which affects the systems change in enthalpy, temperature, and/or change in entropy.
by 505095972
Sun Feb 17, 2019 9:26 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneous Reaction
Replies: 1
Views: 31

Re: Spontaneous Reaction

The equation ∆G=∆H-T∆S shows that even if ∆H and ∆S are negative, T can change the value of the second term and affect spontaneity. More specifically, if ∆S is negative, then the second term would be positive, and if T were great enough, it would make ∆G positive, which would make it non spontaneous...
by 505095972
Sun Feb 17, 2019 9:20 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Determining Spontaneity
Replies: 1
Views: 26

Re: Determining Spontaneity

We can not determine spontaneity based on delta H because the total free energy (delta G) is also affected by t∆S, so at certain temperatures, the free energy would still be positive and it would not be spontaneous. Basically there is another term which must be accounted for in order to determine sp...
by 505095972
Sun Feb 17, 2019 9:18 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free energy and spontaneity
Replies: 2
Views: 22

Re: Gibbs Free energy and spontaneity

A negative delta G means that free energy is being released from the system. This means it is spontaneous (rather than requiring energy to be added to the system which would be non spontaneous). Also, since energy is being released, it increases the entropy in the universe by putting more energy int...
by 505095972
Sun Feb 17, 2019 9:16 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Two Gibbs Free Energy Formulas
Replies: 2
Views: 28

Re: Two Gibbs Free Energy Formulas

Yes, I think you use the equation which allows you to plug in the given information. In other words, you decide which equation to use based on the information given in the problem.
by 505095972
Sun Feb 03, 2019 5:04 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Reversible reaction
Replies: 1
Views: 21

Re: Reversible reaction

I think that they occur when there is an outside stimuli that causes it. I don't think they are just naturally occurring. But I'm not totally sure.
by 505095972
Sun Feb 03, 2019 5:02 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess's Law vs. Rxn Enthalpies
Replies: 2
Views: 39

Re: Hess's Law vs. Rxn Enthalpies

I think they are both ways to find a change in total enthalpy of the system, so it depends on the given information to see which one is easiest to use.
by 505095972
Tue Jan 22, 2019 1:06 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

16 sodiums walk into a room. Who's next?

Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na... BATMAN
by 505095972
Tue Jan 22, 2019 1:04 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

If Avogadro calls, tell him to leave his number.
by 505095972
Tue Jan 22, 2019 1:02 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic vs. Exothermic
Replies: 8
Views: 74

Re: Endothermic vs. Exothermic

An endothermic reaction requires energy, while an exothermic reaction releases energy.
by 505095972
Mon Jan 21, 2019 11:48 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Using Equilibrium Constants to Predict Solubility
Replies: 2
Views: 48

Using Equilibrium Constants to Predict Solubility

How do you use the equilibrium constants to predict solubility? Do you just see which way the reaction favors, and if it is the side with (aq) you know it is going to be soluble but if it favors the other direction then it won’t?
by 505095972
Mon Jan 21, 2019 11:30 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Example 5J.3 Help!
Replies: 2
Views: 27

Example 5J.3 Help!

In the textbook, there is a question asking to predict the effect of compression on the equilibrium composition of the reaction CO2 (g) + H2O (l) —> H2CO3 (aq).

Since H2O is a liquid, that means there is one gaseous/ aqueous molecule on each side, so would compression not affect the equilibrium?
by 505095972
Fri Jan 18, 2019 9:57 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

What kind of dogs do chemists have?

Laboratory retrievers.
by 505095972
Fri Jan 18, 2019 9:56 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

What do you call a wheel made of iron?

A ferrous wheel.
by 505095972
Fri Jan 18, 2019 9:53 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ka vs. Kb
Replies: 12
Views: 127

Ka vs. Kb

Can someone help explain when you use Ka, Kb, or Kc? Are Ka and Kb used whenever H30+ or OH- is a product?
by 505095972
Fri Jan 11, 2019 12:05 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

I tried to write a joke about the periodic table... but I wasn’t quite in my element.
by 505095972
Fri Jan 11, 2019 11:49 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pure Substances
Replies: 2
Views: 32

Re: Pure Substances

I think it is more significant that gases effect activity (which is a concept that is a little more complicated so Dr. Lavelle said we don’t need to really focus on it) and activity is how equilibrium constants are found so therefore gases explain equilibrium constants.
by 505095972
Fri Jan 11, 2019 11:46 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 1
Views: 34

Re: ICE Tables

Yes that is right. You add x proportional to the coefficients in the equation.
by 505095972
Thu Dec 06, 2018 3:10 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Kw
Replies: 2
Views: 40

Kw

So Kw is equal to [H+][OH-]. Is pKw always equal to 14? And if so, why?
by 505095972
Wed Dec 05, 2018 2:22 pm
Forum: Identifying Acidic & Basic Salts
Topic: Rules for acidic & basic salts
Replies: 1
Views: 63

Re: Rules for acidic & basic salts

Salts that are acids lower the pH of the solution, while salts that are bases raise the pH of the solution. For the most part, for salts that are acids the cation is the ion that reacts with water, while for salts that are bases it is the anion that reacts with water.
by 505095972
Wed Dec 05, 2018 2:19 pm
Forum: Amphoteric Compounds
Topic: amphoteric oxides
Replies: 3
Views: 65

Re: amphoteric oxides

They are BeO, Al2O3, Ga2O3, SnO2, Sb2O5, and PbO6.
by 505095972
Wed Dec 05, 2018 2:11 pm
Forum: Naming
Topic: Polyatomic ions and naming
Replies: 7
Views: 76

Re: Polyatomic ions and naming

I think we should probably be familiar with the main ones which are in a chart on page 724 of the 7th edition book!
by 505095972
Fri Nov 30, 2018 11:56 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Oxidation number
Replies: 9
Views: 95

Re: Oxidation number

Also for the s and p block, as you move left to right across the period, the oxidation number goes +1, +2, +3, + or -4, -3, -2, -1.
by 505095972
Tue Nov 27, 2018 5:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi bonds
Replies: 4
Views: 79

Re: Sigma and Pi bonds

So single bonds are sigma bonds. They are an overlap of two orbitals in one place. They can rotate. Pi bonds occur for double and triple bonds. Double bonds have 1 sigma and 1 pi bond, while triple bonds have 1 sigma and 2 pi bonds. Pi bonds basically are an overlap of two orbitals in two places. Th...
by 505095972
Tue Nov 27, 2018 4:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question 3.119
Replies: 2
Views: 28

Re: Question 3.119

Yes exactly. The true bond length is a mix of the single and double bond because of resonance.
by 505095972
Tue Nov 27, 2018 4:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Chapter 4 Sixth Edition Number 11
Replies: 1
Views: 32

Re: Chapter 4 Sixth Edition Number 11

The formal charge on the other two Iodine atoms is 0, so you need to have 3 lone pairs for the formal charge to be -1 on the central atom in order to give the molecule the -1 charge.
by 505095972
Tue Nov 27, 2018 6:25 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Double Bonds as Regions of Electron Density
Replies: 5
Views: 39

Double Bonds as Regions of Electron Density

Do Double bonds count as 1 single region of electron density or two?
by 505095972
Tue Nov 27, 2018 6:23 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw or Square Planar
Replies: 3
Views: 64

Re: Seesaw or Square Planar

Square Planar is when you have 4 bonds but 6 regions of electron density.

Seesaw is when you have 4 bonds but 5 regions of electron density.

Does that help?
by 505095972
Tue Nov 27, 2018 6:18 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Bond Order
Replies: 2
Views: 68

Re: Bond Order

But bond order just refers to how many bonds there are between two atoms, so it isn't hard! Just requires counting.
by 505095972
Tue Nov 27, 2018 6:13 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: Drawing a Dipole
Replies: 6
Views: 64

Drawing a Dipole

When we draw a dipole, do we use the modern convention or the other one? In other words, should the arrow point towards the negative charge or the positive one?
by 505095972
Thu Nov 15, 2018 9:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

When I tell chemistry jokes, I normally get a good reaction.
by 505095972
Thu Nov 15, 2018 9:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

Do you want to hear a post about Nitric Oxide?

NO
by 505095972
Thu Nov 15, 2018 9:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Planar
Replies: 5
Views: 53

Re: Trigonal Planar

They don't have to be double bonds, there just have to be three regions of electron density.
by 505095972
Thu Nov 15, 2018 9:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Single Regions?
Replies: 8
Views: 132

Re: Single Regions?

Well a single bond has 2 electrons, so I would assume it means that. A double bond has 4 electrons, so that would be its electron density. But i'm not totally sure.
by 505095972
Thu Nov 15, 2018 9:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Vsepr Formula
Replies: 7
Views: 64

Re: Vsepr Formula

Basically VESPR is the 3D representation of the lewis structure. However, we won't be asked to draw them, we just have to be able to name the shape and draw the lewis structure.
by 505095972
Thu Nov 08, 2018 10:49 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

I know my friends don't like chemistry jokes... but I tell them periodically.
by 505095972
Thu Nov 08, 2018 10:46 pm
Forum: Dipole Moments
Topic: Dipole - Dipole vs. Hydrogen Bonding
Replies: 4
Views: 63

Dipole - Dipole vs. Hydrogen Bonding

In High School, I thought we learned the hydrogen bonding was the weakest form of bonding, but my notes show that Dipole-Dipole bonds are actually weaker. Why is that?
by 505095972
Thu Nov 08, 2018 10:42 pm
Forum: Dipole Moments
Topic: dipole interaction
Replies: 2
Views: 47

Re: dipole interaction

Polarizability is how easy it is to pull electrons from one atom in a molecule towards the other. When this happens, a dipole moment occurs, because the electrons are pulled towards one of the atoms, making it more positively charged. Dispersion forces have fluctuating electron distributions, where ...
by 505095972
Thu Nov 01, 2018 4:43 pm
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 14863

New Chemistry Helping make Plastic Safer!

A professor at UCSC was able to make a plastic that doesn't leach chemicals into its surroundings (like PVC does)! This can have massive environmental effects if companies will start using her new nonmigratory plasticizers.
https://www.eurekalert.org/pub_releases ... 103118.php
by 505095972
Thu Nov 01, 2018 4:40 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

OMG! Did you hear that Magnesium and Oxygen are a couple?!
by 505095972
Thu Nov 01, 2018 4:38 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 804383

Re: Post All Chemistry Jokes Here

OMG! Did you hear that Oxygen and Magnesium are a couple?!
by 505095972
Thu Nov 01, 2018 4:24 pm
Forum: Octet Exceptions
Topic: Boron Trifluoride class example
Replies: 3
Views: 60

Re: Boron Trifluoride class example

Fluorine is really unstable when it has a positive charge, so much so that I don't really think it ever happens. So it is a bad thing because it just isn't realistic or really possible.
by 505095972
Fri Oct 26, 2018 11:38 am
Forum: Student Social/Study Group
Topic: Chemistry News
Replies: 38
Views: 14863

Re: Chemistry News

Nobel Prize in Chemistry Goes to a Woman for the Fifth Time in History I know this is from earlier this month, but I think it is super cool and wanted to share! https://www.nytimes.com/2018/10/03/science/frances-arnold-nobel-prize-chemistry.html?rref=collection%2Ftimestopic%2FChemistry&action=cl...
by 505095972
Fri Oct 26, 2018 11:34 am
Forum: Ionic & Covalent Bonds
Topic: Focus 2D #3 - HW Problem
Replies: 3
Views: 128

Re: Focus 2D #3 - HW Problem

That is confusing to me too, because I thought if it has a high polarizing energy, it will be more likely to give an electron away/ take an electron, making an ionic bond more likely.
by 505095972
Fri Oct 26, 2018 11:27 am
Forum: Ionic & Covalent Bonds
Topic: Ionization Energy vs. Electronegativity
Replies: 5
Views: 62

Ionization Energy vs. Electronegativity

I'm a little confused. What is ionization energy and how is it different from electronegativity?
by 505095972
Fri Oct 19, 2018 3:01 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 1E.25
Replies: 2
Views: 52

Re: Homework 1E.25

So basically for A), we know that there is 1 valence electron that will be in an s orbital, so they wrote ns^1 to mean at any energy level, the orbital will be the s shape, and there will be one electron in the orbital. For B), we know that the valence shell of any of the atoms (at any energy level)...
by 505095972
Fri Oct 19, 2018 2:50 pm
Forum: *Shrodinger Equation
Topic: Schrodingers Equation and Probability Density
Replies: 2
Views: 89

Re: Schrodingers Equation and Probability Density

To add on to that, it basically helps calculate the orbital that a specific electron is in by telling us where the electron will probably be.
by 505095972
Fri Oct 19, 2018 2:47 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation Question
Replies: 3
Views: 88

Re: Shrodinger Equation Question

We don't need to know how to do equations with the wave function, but it is important to know that the wave function squared is gives you the probability of finding an electron in a certain area (that energy shell).
by 505095972
Thu Oct 11, 2018 7:50 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Balmer and Lyman series
Replies: 3
Views: 64

Re: Balmer and Lyman series

I think it is basically the same equation, but it is just trying to determine the change in frequency when it is excited, rather than the frequency at a certain instant.
by 505095972
Thu Oct 11, 2018 7:46 pm
Forum: Einstein Equation
Topic: Spectroscopy experimenting
Replies: 4
Views: 119

Re: Spectroscopy experimenting

This is confusing to me too... Do you mean that if there is energy absorbed from the light by the metal that is exactly the same as the work function, the electrons are excited but remain with the metal rather than being ejected?
by 505095972
Thu Oct 11, 2018 2:45 pm
Forum: Properties of Electrons
Topic: Explaining Millikan's Experiment
Replies: 2
Views: 65

Explaining Millikan's Experiment

Hi there,

In the textbook, Robert Millikan's experiment to determine the charge of an electron using oil droplets was explained, but I don't really understand it. How could the "smallest increment of charge between droplets" be the charge of one electron? What does that mean?
by 505095972
Fri Oct 05, 2018 11:33 pm
Forum: Limiting Reactant Calculations
Topic: Calculating Maximum Mass
Replies: 5
Views: 177

Re: Calculating Maximum Mass

I'm struggling as well, but I think you have to use stoichiometry to solve for grams of Cu(OH)2 starting with 2.00 g NaOH and then again with the .80 mL of Cu(NO3)2 to determine which is the limiting reactant. However, I'm having some trouble making the equation at the moment.
by 505095972
Fri Oct 05, 2018 3:52 pm
Forum: Empirical & Molecular Formulas
Topic: Compound Names
Replies: 9
Views: 268

Re: Compound Names

In some of the homework problems they asked for the formulas of compounds given their names (E7 in particular asks "epsom salts consist of magnesium sulfate heptahydrate. Write its formula.) I'm not sure how to do that. Can anyone help?
by 505095972
Fri Oct 05, 2018 11:40 am
Forum: Molarity, Solutions, Dilutions
Topic: Water Added to Solution Placed in a New Flask
Replies: 3
Views: 57

Re: Water Added to Solution Placed in a New Flask

You can use the equation Vinitial*M initial = Vfinal*M final to solve for M final

You find M initial by converting the 5.00 g KMnO4 to moles per liter using the known 150 mL volume and stoichiometry.

Then you put that concentration and volume into the equation and solve for M final.

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