I know a guy who cooled himself to -273.15C.
He was 0K.
Search found 65 matches
- Sun Mar 17, 2019 11:37 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
- Sun Mar 17, 2019 11:37 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why do chemists like nitrates so much?
Because they're cheaper than day rates.
Because they're cheaper than day rates.
- Sun Mar 17, 2019 11:36 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
What do you call a tooth in a glass of water?
A one molar solution.
A one molar solution.
- Sun Mar 17, 2019 11:36 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
If the Queen farts, is it a noble gas?
- Sun Mar 17, 2019 11:34 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Organic chemistry is difficult.
Those who study it have alkynes of trouble.
Those who study it have alkynes of trouble.
- Sun Mar 17, 2019 11:28 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
What kind of fish is made out of 2 sodium atoms?
2 Na
2 Na
- Sun Mar 17, 2019 11:27 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
A neutron walks into a bar. He asks the bartender, “How much for a beer?” The bartender offers him a warm smile and says, “For you, no charge”.
- Sun Mar 17, 2019 10:11 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why are chemists great for solving problems?
They have all the solutions.
They have all the solutions.
- Sun Mar 17, 2019 10:10 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."
- Sun Mar 17, 2019 10:08 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Someone threw sodium chloride at me.
I yelled, “That’s a salt!”
I yelled, “That’s a salt!”
- Sun Mar 17, 2019 10:03 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
What do dipoles say in passing?
"Have you got a moment?"
"Have you got a moment?"
- Sun Mar 17, 2019 10:01 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Two atoms are walking down the street…
One atom says to the other, “Hey! I think I lost an electron!” The other asks, “Are you sure?”
“Yes, I’m positive!”
One atom says to the other, “Hey! I think I lost an electron!” The other asks, “Are you sure?”
“Yes, I’m positive!”
- Sun Mar 17, 2019 10:00 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why can you never trust atoms?
They make up everything!
They make up everything!
- Sun Mar 17, 2019 9:33 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why can you never trust atoms?
They make up everything!
They make up everything!
- Sun Mar 17, 2019 9:30 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why did the acid go to the gym?
To become a buffer solution.
To become a buffer solution.
- Sun Mar 17, 2019 9:29 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why did the acid go to the gym?
To become a buffer solution.
To become a buffer solution.
- Sun Mar 17, 2019 9:27 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
What do you do with a dead chemist?
Barium.
Barium.
- Sun Mar 17, 2019 9:26 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3622210
Re: Post All Chemistry Jokes Here
Why did the noble gas cry?
Because all his friends Argon.
Because all his friends Argon.
- Fri Mar 08, 2019 4:10 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Test 2
- Replies: 6
- Views: 1840
Test 2
Can someone please explain why delta G is less than 0 for the following two processes?
The precipitation of snowflakes inside a cloud at -10 C and 0.839 atm.
The sublimation of dry ice in a warm room.
The precipitation of snowflakes inside a cloud at -10 C and 0.839 atm.
The sublimation of dry ice in a warm room.
- Thu Feb 28, 2019 12:51 pm
- Forum: Balancing Redox Reactions
- Topic: Basic Solutions
- Replies: 3
- Views: 438
Re: Basic Solutions
An alternative way to balance redox reactions in basic solutions is just to balance it like you would for an acidic solution, then add OH- for every H+ there is on both sides of the equation, and then use H+ + OH- -> H2O so that there are only OH- and H2O molecules in the final balanced equation.
- Mon Feb 11, 2019 11:06 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: H and S relationship
- Replies: 1
- Views: 243
Re: H and S relationship
∆S = q(rev)/T at constant temperature and q = ∆H at constant pressure. Thus, ∆S = ∆H/T at constant temperature and pressure.
This equation is applicable to changes in entropy of phase changes.
This equation is applicable to changes in entropy of phase changes.
- Mon Feb 11, 2019 11:01 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Deriving Formulas
- Replies: 2
- Views: 368
Re: Deriving Formulas
I don't believe the outlines include derivation of the formulas but I think knowing them is helpful in understanding when to apply which formulas.
- Sun Feb 03, 2019 3:29 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U
- Replies: 4
- Views: 477
Re: Delta U
The change in internal energy is a function of only the initial and final states.
- Sun Feb 03, 2019 3:06 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta H vs q
- Replies: 9
- Views: 935
Re: delta H vs q
Change in enthalpy (delta H) is the amount of heat (q) absorbed or released at constant pressure.
- Sun Feb 03, 2019 3:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy
- Replies: 3
- Views: 413
Re: Enthalpy
Enthalpy is the amount of heat released or absorbed at constant pressure.
- Sat Jan 19, 2019 7:42 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Explaining pressure increase in terms of concentration
- Replies: 2
- Views: 373
Re: Explaining pressure increase in terms of concentration
If pressure is increased by decreasing volume, then concentration increases (C=n/V). We can calculate Q using the new concentrations and compare that with K to see which way the reaction shifts. In this case, we can look at [O2]^3/[O3]^2 to know that increasing concentration would cause Q>K and the ...
- Sat Jan 19, 2019 7:25 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Pressure
- Replies: 4
- Views: 560
Re: Pressure
It's also important to note that we're comparing only the number of moles of gases.
- Sat Jan 19, 2019 4:17 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: strong acids and bases
- Replies: 2
- Views: 405
Re: strong acids and bases
The strong acids and bases can be found on F83 in the 6th edition textbook:
Strong acids: HBr, HCl, HI, HNO3, NClO4, HClO3, H2SO4
Strong bases: Group 1 hydroxides, alkaline earth metal hydroxides (Ca(OH)2, Sr(OH)2, Ba(OH)2), Group 1 and Group 2 oxides
Strong acids: HBr, HCl, HI, HNO3, NClO4, HClO3, H2SO4
Strong bases: Group 1 hydroxides, alkaline earth metal hydroxides (Ca(OH)2, Sr(OH)2, Ba(OH)2), Group 1 and Group 2 oxides
- Sat Jan 12, 2019 9:28 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: doubling pressure
- Replies: 2
- Views: 274
Re: doubling pressure
Lavelle was giving an example of how a reaction responds to minimize the effect of increasing pressure (by decreasing volume). If P doubled (V halved), then there would be new initial concentrations (since concentration=moles/volume). Q would then be solved for these new concentrations so that we co...
- Sat Jan 12, 2019 9:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc and Kp
- Replies: 4
- Views: 409
Re: Kc and Kp
Kc is the equilibrium constant calculated using molar concentrations of the products and reactants. Kp is the equilibrium constant using partial pressures of the products and reactants. You can write either the Kc or Kp for a problem involving gases only.
- Sat Jan 12, 2019 9:16 pm
- Forum: Ideal Gases
- Topic: R and T
- Replies: 3
- Views: 446
Re: R and T
R is a constant that will be given to us on tests. T is not a constant but must be given to us to use the ideal gas law.
- Sun Dec 09, 2018 3:49 pm
- Forum: Coordinate Covalent Bonds
- Topic: Chelates
- Replies: 4
- Views: 738
Re: Chelates
They're ring structures that are formed by polydentate ligands bonding to a transition metal.
- Sun Dec 09, 2018 3:48 pm
- Forum: Coordinate Covalent Bonds
- Topic: Identifying Polydentates
- Replies: 4
- Views: 794
Re: Identifying Polydentates
You can look at the structure or you can memorize which ligands are polydentate (there's a list of ligands we need to know on Lavelle's website).
- Sun Dec 09, 2018 3:45 pm
- Forum: Coordinate Covalent Bonds
- Topic: polydentates
- Replies: 5
- Views: 633
Re: polydentates
Easiest way would be to memorize the common polydentate ligands.
- Sun Dec 09, 2018 3:40 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: Strength
- Replies: 5
- Views: 925
Re: Strength
Correct
- Sun Dec 09, 2018 3:38 pm
- Forum: Hybridization
- Topic: Hybrid Orbitals
- Replies: 6
- Views: 700
Re: Hybrid Orbitals
If it's identifying the hybrid orbitals used by an atom, I think it's just sp, sp2, sp3, etc.
- Sun Dec 09, 2018 3:33 pm
- Forum: Biological Examples
- Topic: Cisplatin
- Replies: 3
- Views: 714
Re: Cisplatin
There's a picture of it here: https://en.wikipedia.org/wiki/Cisplatin
- Sun Dec 09, 2018 3:25 pm
- Forum: Air Pollution & Acid Rain
- Topic: Acid Rain
- Replies: 24
- Views: 3946
Re: Acid Rain
SO2 reacts with water vapor to form acidic rain. (SO2 comes from burning petroleum products, coal, etc.)
SO2(g) + H2O(l) → H2SO3(aq)
SO2(g) + H2O(l) → H2SO3(aq)
- Sun Dec 09, 2018 3:23 pm
- Forum: Air Pollution & Acid Rain
- Topic: Acid Rain Formation
- Replies: 6
- Views: 829
Re: Acid Rain Formation
From the lecture slides:
Sulfur dioxide + water → sulphurous acid
SO2(g) + H2O(l) → H2SO3(aq)
SO2(g) comes from burning petroleum products, coal, etc.
SO2(g) reacts with water vapor to form acidic rain.
Sulfur dioxide + water → sulphurous acid
SO2(g) + H2O(l) → H2SO3(aq)
SO2(g) comes from burning petroleum products, coal, etc.
SO2(g) reacts with water vapor to form acidic rain.
- Sun Dec 09, 2018 3:07 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Why HF is a weaker acid than HCl
- Replies: 17
- Views: 16308
Re: Why HF is a weaker acid than HCl
HCl is a stronger acid because the bond between H and Cl is weaker than the bond between H and F (this is because Cl has a greater atomic radius). HClO is a stronger acid than HBrO because the resulting anion of HClO is more stable as a result of Cl having a greater electron withdrawing power than Br.
- Sat Dec 08, 2018 1:56 pm
- Forum: Lewis Acids & Bases
- Topic: 6A.15
- Replies: 2
- Views: 366
- Sun Nov 25, 2018 8:26 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity
- Replies: 1
- Views: 228
Re: Polarity
CH2Cl2 has a tetrahedral shape, so the dipole moments that are formed between the Cl's and the C don't cancel out.
- Sun Nov 25, 2018 8:17 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2 Lone Pairs, Placement
- Replies: 3
- Views: 681
Re: 2 Lone Pairs, Placement
The lone pairs should be placed so as to minimize electron-pair repulsions. Since H2O has a tetrahedral electron arrangement, the lone pairs will always be next to each other no matter where you place them. XeF4 has an octahedral electron arrangement, so placing the 2 lone pairs on opposite sides of...
- Thu Nov 22, 2018 3:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: CH 4 4.19 HW 6TH EDITION
- Replies: 2
- Views: 412
Re: CH 4 4.19 HW 6TH EDITION
What's the correct lewis structure for S2O3 2-? I know that the double bonds don't matter for the shapes and bond angles, but I'm getting varied answers on the internet.
- Sat Nov 17, 2018 11:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Square Planar
- Replies: 5
- Views: 540
Re: Square Planar
If the electron geometry is an octahedral and there are 2 lone pairs, then the molecular shape will be square planar.
- Sat Nov 17, 2018 11:40 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: see saw
- Replies: 2
- Views: 201
Re: see saw
Here's a visual: https://www.dlt.ncssm.edu/tiger/diagram ... w_a_3D.jpg
- Sat Nov 17, 2018 11:28 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular shape vs electron geometry
- Replies: 4
- Views: 389
Re: Molecular shape vs electron geometry
The molecular shape looks at the bonded atoms only, while the electron geometry includes the bonded atoms and lone pairs.
- Sun Nov 11, 2018 11:31 am
- Forum: Bond Lengths & Energies
- Topic: Strength of Bonds
- Replies: 9
- Views: 1080
Re: Strength of Bonds
Intermolecular forces determine boiling point, but I don't believe intramolecular forces (bonds) do.
- Sun Nov 11, 2018 11:20 am
- Forum: Dipole Moments
- Topic: Dipoles and Molarity
- Replies: 2
- Views: 432
Re: Dipoles and Molarity
Polarity refers to the unequal sharing of electrons between atoms depending on their differing electronegativities. A dipole moment is created as a result of these polar bonds.
A molecule may have a dipole moment depending on the geometry of the polar bonds.
A molecule may have a dipole moment depending on the geometry of the polar bonds.
- Sun Nov 11, 2018 10:59 am
- Forum: Bond Lengths & Energies
- Topic: Interaction Potential Energy
- Replies: 2
- Views: 373
Re: Interaction Potential Energy
It is an attractive force.
- Thu Nov 01, 2018 11:08 pm
- Forum: Lewis Structures
- Topic: 7th Edition 2.B.9
- Replies: 5
- Views: 818
Re: 7th Edition 2.B.9
Metals tend to form cations and nonmetals tend to form anions.
- Wed Oct 31, 2018 10:51 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Ag+ Configuration
- Replies: 5
- Views: 1927
Re: Ag+ Configuration
An electron configuration with a full (or half full) 4d-orbital is more stable than a partially filled 4d-orbital.
- Wed Oct 31, 2018 10:42 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Homework 2.43e
- Replies: 3
- Views: 371
Re: Homework 2.43e
Actually, the phenomenon also applies to Ag and Au which are in the 5th and 6th periods. Tungsten and the heavier elements in the Cr group are just more stable without promoting an s electron to half fill a d-orbital: viewtopic.php?t=22959
- Sun Oct 28, 2018 3:26 pm
- Forum: Trends in The Periodic Table
- Topic: Isoelectronic atoms sizes [ENDORSED]
- Replies: 3
- Views: 539
Re: Isoelectronic atoms sizes [ENDORSED]
For isoelectronic atoms, the size would be dependent on the number of protons.
- Sun Oct 28, 2018 3:22 pm
- Forum: Trends in The Periodic Table
- Topic: Diagonal Relationships
- Replies: 2
- Views: 350
Re: Diagonal Relationships
I think elements in the same group will generally be more similar since they have the same number of valence electrons. This similar electron configuration gives them similar chemical and physical properties.
- Sun Oct 28, 2018 3:01 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Copper exception
- Replies: 4
- Views: 392
Re: Copper exception
An electron configuration with a completely full or half full 3d subshell is more stable.
- Sun Oct 21, 2018 5:06 pm
- Forum: *Shrodinger Equation
- Topic: Shrodinger Explained
- Replies: 2
- Views: 245
Re: Shrodinger Explained
Schrodinger's equation uses a wave function to describe an electron, with its wavelike properties and indeterminacy in momentum and position. The wave function squared tells us the electron density distribution in an atom.
- Sun Oct 21, 2018 4:51 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Homework Problem 1.13 (Sixth Edition)
- Replies: 1
- Views: 138
Re: Homework Problem 1.13 (Sixth Edition)
n1 should be smaller than n2. Another way to think of the equation is R * (1/n(final)^2 - 1/n(initial)^2), assuming that the electron transitions from a higher to lower energy level.
- Sun Oct 21, 2018 4:21 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Heisenberg Equation Confusion
- Replies: 4
- Views: 390
Re: Heisenberg Equation Confusion
We don't need to know the derivation process - it's difficult and you would learn it in a graduate school course.
- Sat Oct 13, 2018 2:23 pm
- Forum: DeBroglie Equation
- Topic: Wavelike Properties
- Replies: 2
- Views: 165
Re: Wavelike Properties
All objects have wavelike properties, but it is only noticed for moving objects with extremely small mass. For the purpose of this class, anything with a de broglie wavelength smaller than 10^-18 m is considered not measurable.
- Thu Oct 11, 2018 3:01 pm
- Forum: Properties of Electrons
- Topic: Help with question 1.13
- Replies: 2
- Views: 226
Re: Help with question 1.13
For part a, calculate the frequency by using the Rydberg formula and plugging in n(initial) = 4 and n(final) = 2. Then, solve for the wavelength by using c/v. For part b, you know that the electron transitions from a higher energy level to n=2. This is all you need to know to determine whether the t...
- Thu Oct 11, 2018 2:48 pm
- Forum: Properties of Light
- Topic: Photons
- Replies: 4
- Views: 172
Re: Photons
If you are looking at the wave model of light, then increasing the intensity of the light increases its amplitude. If you are viewing light as a particle, increasing the intensity of light increases the number of photons. It is when frequency of the light is increased that energy is increased and el...
- Sat Oct 06, 2018 10:23 am
- Forum: Significant Figures
- Topic: Using Sig Figs Throughout a Problem?
- Replies: 6
- Views: 1163
Re: Using Sig Figs Throughout a Problem?
If you're doing a multi-step calculation with various operations and have to add/subtract numbers in one of the steps, the number of sig figs could change to be less than the least number of sight figs given in the problem. Would we use that number of sig figs for our final answer?
- Tue Oct 02, 2018 9:26 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Confused about molarity concept
- Replies: 4
- Views: 680
Re: Confused about molarity concept
As Andrew said, 9.8 mL of KMnO4 is poured into a beaker and water is added up to the 250 mL mark. So, the stock solution is being diluted with water, and the concentration of the solution is decreased since there is now the same amount of solute in more water.
- Tue Oct 02, 2018 9:15 pm
- Forum: Empirical & Molecular Formulas
- Topic: Solving For Empirical and Molecular Formulas
- Replies: 4
- Views: 1914
Re: Solving For Empirical and Molecular Formulas
Finding the mass percentage would not be needed for this question. Unless the question asks for the mass percentages, I wouldn't take an extra step to find it when the moles can be calculated directly from the masses given. However, it doesn't hurt to calculate the mass percentage, so it can be up t...