Why do sodium, carbon, hydrogen, and oxygen taste so good together?
- NaCHOs
Search found 35 matches
- Tue Mar 21, 2017 11:18 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3915216
- Sun Mar 12, 2017 11:54 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Butane - Gauche formation
- Replies: 1
- Views: 481
Re: Butane - Gauche formation
The energy is determined by how far the neighboring atoms are spaced out, not how big the angles are.
- Sun Mar 05, 2017 12:46 pm
- Forum: *Free Energy of Activation vs Activation Energy
- Topic: exergonic vs exothermic
- Replies: 2
- Views: 1330
Re: exergonic vs exothermic
Exergonic refers to the negative change in Gibbs free energy, whereas exothermic refers to the negative change in enthalpy.
- Sun Feb 26, 2017 11:47 pm
- Forum: *Electrophiles
- Topic: Electrophile Vs. Nucleophile
- Replies: 3
- Views: 916
Re: Electrophile Vs. Nucleophile
I suppose when you say "it is not obvious," you mean that the elements do not have obvious partial charges that are used to classify them as nucleophile or electrophile. In this case, you would need to look at the elements' likelihood of accepting or donating electrons. If the element acce...
- Sun Feb 19, 2017 9:42 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Unique Rate of A Reaction
- Replies: 2
- Views: 606
Re: Unique Rate of A Reaction
Some students asked the same question couple years ago, and here is what Dr. Lavelle posted back then: "A unique rate is a rate of appearance/disappearance of any of the species in a reaction divided by its stoichiometric coefficient. A unique rate will be the same for each reactant or product....
- Sun Feb 12, 2017 7:37 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: constant volume and pressure
- Replies: 1
- Views: 749
Re: constant volume and pressure
Cv,m stands for the molar specific heat capacity under constant volume, so you use Cv,m when volume is constant. Cv,m = 3R/2 because the object is assumed to behave IDEALLY. This does not mean that Multiplying Cv,m with "n" gives you the specific heat capacity of whatever object you are ca...
- Sat Feb 04, 2017 9:31 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3915216
- Wed Jan 25, 2017 1:38 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Calculating Internal Energy Change
- Replies: 1
- Views: 520
Re: Calculating Internal Energy Change
I am not sure if I am correct, but here is what I think. The heat capacity of the calorimeter remains unchanged regardless of the rxn that takes place inside because heat capacity measures how much heat is needed to rise the temperature of the system by 1 degree. Heat capacity is an intensive proper...
- Sun Jan 22, 2017 12:19 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy
- Replies: 2
- Views: 536
Re: Entropy
The two factors that change entropy (the probability of a system being in a particular state) are heat and expansion. The entropy associate with heat is called THERMAL ENTROPY, which is calculated by reversible heat divided by temperature. The entropy associated with expansion is called is RESIDUAL ...
- Mon Jan 16, 2017 9:36 pm
- Forum: Phase Changes & Related Calculations
- Topic: Adiabatic
- Replies: 1
- Views: 492
Re: Adiabatic
Adiabatic means that no heat leaves or enters the system.
- Sat Dec 03, 2016 11:12 am
- Forum: Ideal Gases
- Topic: Q and K [ENDORSED]
- Replies: 35
- Views: 3242
Re: Q and K [ENDORSED]
There is no difference between the two formula.
- Sun Nov 20, 2016 9:28 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strong Acid or Weak Acid
- Replies: 3
- Views: 952
Re: Strong Acid or Weak Acid
the strong acids are usually composed of hydrogen + group 1 or group 2 elements because these compound desolve easily in solvent, thus contributing a large increase to the concentration of hydronium ions. I don't think there's a way in determining the strength of an acid based simply on the chemical...
- Sun Nov 20, 2016 9:20 pm
- Forum: Conjugate Acids & Bases
- Topic: pOH from pH [ENDORSED]
- Replies: 2
- Views: 742
Re: pOH from pH [ENDORSED]
Remember that pOH and pH are reverse of each other.
First, you calculate the "-log[conc. of hydronium]" which gives you pH
Then, from the equation "pH + pOH = 14" that we derived in class, you can plug the pH value and solve the equation.
First, you calculate the "-log[conc. of hydronium]" which gives you pH
Then, from the equation "pH + pOH = 14" that we derived in class, you can plug the pH value and solve the equation.
- Sun Nov 13, 2016 7:52 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: The difference between K, Kc, and Kp
- Replies: 2
- Views: 674
Re: The difference between K, Kc, and Kp
"K" does not mean any particular number in chemical equilibrium
"Kc" is the equilibrium concentration
"Kp" is the equilibrium pressure
"Kc" is the equilibrium concentration
"Kp" is the equilibrium pressure
- Sun Nov 06, 2016 9:45 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: Boron M.O. and Bond Order?
- Replies: 1
- Views: 855
Re: Boron M.O. and Bond Order?
Bond order explains bond stability. It is not an indication of how many bonds a atom can form.
- Sun Oct 30, 2016 3:57 pm
- Forum: Hybridization
- Topic: Lone pairs [ENDORSED]
- Replies: 1
- Views: 514
Re: Lone pairs [ENDORSED]
Lone pair is considered as an electron density region, so it does affect the number of hybridization orbitals.
The hybridization orbitals for a central atom with three bonds and one lone pair are sp3.
The hybridization orbitals for a central atom with three bonds and one lone pair are sp3.
- Sun Oct 30, 2016 3:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape and Polarity
- Replies: 2
- Views: 833
Re: Molecular Shape and Polarity
One general rule to determine the polarity of a molecule is to see whether the bonding electron pairs are scattered evenly around the central atom. If they are evenly scattered, then the molecule is nonpolar. (The idea behind this guideline is that the difference between partial charges of surround...
- Sat Oct 22, 2016 2:44 pm
- Forum: Electronegativity
- Topic: HW 3.59
- Replies: 2
- Views: 515
Re: HW 3.59
After actually doing #59, and I used double bond; I think it would be better to put the extra electron on chlorine because chlorine can have expanded octet.
adding electron to oxygen would give you a final charge of -1 instead of zero
adding electron to oxygen would give you a final charge of -1 instead of zero
- Sat Oct 22, 2016 1:14 pm
- Forum: Electronegativity
- Topic: HW 3.59
- Replies: 2
- Views: 515
Re: HW 3.59
At this point, I would refer back to the octet rule.
- Sat Oct 22, 2016 1:10 pm
- Forum: Octet Exceptions
- Topic: Octet exceptions and double bonds
- Replies: 3
- Views: 774
Re: Octet exceptions and double bonds
I think it does have to do with the formal charges. The lewis structure for XeOF4 has FC of zero.
One important thing to note is that having a negative partial charge is not preferable because the surrounding atoms have higher electron affinity.
One important thing to note is that having a negative partial charge is not preferable because the surrounding atoms have higher electron affinity.
- Sat Oct 22, 2016 1:00 pm
- Forum: Lewis Structures
- Topic: When are you supposed to know?
- Replies: 1
- Views: 479
Re: When are you supposed to know?
You use brackets "[ ]" for ionic bonds.
You use dashes "___" for covalent bonds.
And you use the difference in electronegativity to determine whether a molecule has ionic or covalent bonds.
You use dashes "___" for covalent bonds.
And you use the difference in electronegativity to determine whether a molecule has ionic or covalent bonds.
- Sat Oct 22, 2016 12:53 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Px, Py, Pz [ENDORSED]
- Replies: 5
- Views: 13986
Re: Px, Py, Pz [ENDORSED]
I confirmed with Dr. Lavelle that assigning coordinates ( x, y, z, etc) to orbitals is arbitrary. He will not test us on that, so we do not have to worry too much. :)
- Fri Oct 21, 2016 1:45 pm
- Forum: Ionic & Covalent Bonds
- Topic: Order or formula
- Replies: 2
- Views: 554
Re: Order or formula
Also, if you have part of a formula in parenthesis, such as
(NH2) XYZ , where X, Y, and Z represent some random atoms
the 2 hydrogen atoms are attached to the nitrogen atom when drawing Lewis Structure.
(NH2) XYZ , where X, Y, and Z represent some random atoms
the 2 hydrogen atoms are attached to the nitrogen atom when drawing Lewis Structure.
- Fri Oct 21, 2016 1:39 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Px, Py, Pz [ENDORSED]
- Replies: 5
- Views: 13986
Re: Px, Py, Pz [ENDORSED]
They describe the locations of electrons in a P-orbital. So instead of saying "these electron are in the front and back," we can say "their positions are on the x-axis" since they are in P-orbital, we state their location as "Px" same idea for Py and Pz Do you know how...
- Fri Oct 21, 2016 1:07 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Meaning
- Replies: 2
- Views: 1139
Re: Formal Charge Meaning
What is the actual meaning of the formal charge of an atom, and how does it affect the compound? I understand that we want all the atoms to have formal charges of 0 because this indicates that it is the most "stable", but what does this really mean/refer to? You want the formal charge of ...
- Fri Oct 21, 2016 12:39 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 6
- Views: 1092
Re: Lewis Structures
Joslyn_Santana_3A wrote:Here is an example of Xe breaking the octet rule.
Yes, you are right that both the S and P orbitals are filled, but Xe also has 5d orbitals that is shown in period 6 on the periodic table, so the extra pairs of bonds occupy the d-orbitals
- Sat Oct 15, 2016 11:46 pm
- Forum: Trends in The Periodic Table
- Topic: d-block electron configuraitons
- Replies: 4
- Views: 1112
Re: d-block electron configuraitons
We must note that before atomic number 20, there''s no d-orbitals. The general guideline is that once the d-orbitals at n-th energy level are filled, their energy levels drop below the s-orbitals of n+1st energy level; therefore d-orbitals, if exist, from n-th energy level should be written before s...
- Sat Oct 15, 2016 11:22 pm
- Forum: Resonance Structures
- Topic: Electrons in Resonance [ENDORSED]
- Replies: 4
- Views: 947
Re: Electrons in Resonance [ENDORSED]
The electrons are in the state of somewhere in between.
- Sun Oct 09, 2016 10:11 am
- Forum: DeBroglie Equation
- Topic: Question: How should I decide if I use DeBroglie Equation or the equation for Kinetic Energy?
- Replies: 4
- Views: 798
Re: Question: How should I decide if I use DeBroglie Equation or the equation for Kinetic Energy?
Even thought both equations contain velocity, calculating Ek doesn't help you to solve for wavelength. At least with what we have learned so far, we do not know how to convert Ek to wavelength or frequency.
- Sun Oct 09, 2016 9:59 am
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Px, Py, Pz [ENDORSED]
- Replies: 5
- Views: 13986
Re: Px, Py, Pz [ENDORSED]
They describe the locations of electrons in a P-orbital. So instead of saying "these electron are in the front and back," we can say "their positions are on the x-axis"
since they are in P-orbital, we state their location as "Px"
same idea for Py and Pz
since they are in P-orbital, we state their location as "Px"
same idea for Py and Pz
- Sun Oct 09, 2016 9:51 am
- Forum: *Shrodinger Equation
- Topic: wavefunction, psi, and orbitals [ENDORSED]
- Replies: 1
- Views: 1477
Re: wavefunction, psi, and orbitals [ENDORSED]
Based on the information given by the following website http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/wvfun.html#c2 It seems to me that: Psi itself gives you a prediction of position and time of an electron. Psi gives you the shape of an orbital Psi square represents to probability of finding a...
- Fri Oct 07, 2016 7:41 pm
- Forum: Properties of Light
- Topic: Problem 7 Quiz 1 Preparation in the Workbook [ENDORSED]
- Replies: 1
- Views: 445
Re: Problem 7 Quiz 1 Preparation in the Workbook [ENDORSED]
Hertz = 1/second or second^-1
so if we ignore the number, the calculation would look like the following:
(meter*second^-1) / (meter) = second^1 = hertz
which corresponds to
speed of light / wavelength = frequency
so if we ignore the number, the calculation would look like the following:
(meter*second^-1) / (meter) = second^1 = hertz
which corresponds to
speed of light / wavelength = frequency
- Fri Oct 07, 2016 7:22 pm
- Forum: Trends in The Periodic Table
- Topic: orbitals
- Replies: 2
- Views: 620
Re: orbitals
For your second question:
the elements in the s-block go from group(column) 1 to group 2
the elements in the p-block go from group 13 to 18
the elements in the d-block go from group 3-12
f-block would be the last two periods (6 and 7)
the elements in the s-block go from group(column) 1 to group 2
the elements in the p-block go from group 13 to 18
the elements in the d-block go from group 3-12
f-block would be the last two periods (6 and 7)
- Wed Sep 28, 2016 9:49 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation Post Assessment Problem
- Replies: 3
- Views: 2407
Re: Rydberg Equation Post Assessment Problem
1.14E14 = -3.29E15 [(1/n^2) - (1/4^2)]
n^2 = 1/(1.14E14/-3.29E15 + 1/16)
square root both sides and you will get an answer that is close to an integer. :)
n^2 = 1/(1.14E14/-3.29E15 + 1/16)
square root both sides and you will get an answer that is close to an integer. :)
- Tue Sep 27, 2016 11:18 am
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Rydberg Equation Post Assessment Problem
- Replies: 3
- Views: 2407
Re: Rydberg Equation Post Assessment Problem
Given the shortcut formula: frequency = -R [(1/n*2) - (1/N*2)] in which "n" is the initial energy level, and "N" is the final energy level. you basically substitute all the values into the formula and solve for "n". if the negative signs are confusing, try to distribute...