Search found 29 matches
- Sun Jun 10, 2018 3:39 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Calculating pH of a solution given molarity
- Replies: 3
- Views: 839
Calculating pH of a solution given molarity
If you have 0.550 M Na2O solution, does this translate to 0.550 M of NaOH? If so, why does pOH = -log[0.550] yield such a small value?
- Sun Jun 10, 2018 3:35 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Methyl-2-Cyanoacrylate
- Replies: 1
- Views: 362
Methyl-2-Cyanoacrylate
Given the abbreviate structure, I'm not sure where all the hydrogen atoms belong, and how to find the approximate bond angles for this molecule.
- Sun Jun 10, 2018 3:16 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Heme complex structure_coordination number
- Replies: 1
- Views: 324
Heme complex structure_coordination number
How can you tell the coordination number of the center Fe atom? Why are there solid and dotted lines extending towards the N atoms?
- Sat Jun 02, 2018 2:02 pm
- Forum: Hybridization
- Topic: How to identify pi and sigma bonds
- Replies: 4
- Views: 731
Re: How to identify pi and sigma bonds
Why can there be two pi bonds but not two sigma bonds.
- Sat Jun 02, 2018 1:58 pm
- Forum: Hybridization
- Topic: σ bonds
- Replies: 9
- Views: 1026
Re: σ bonds
How come double bonds and triple bonds have pi bonds?
- Sat Jun 02, 2018 1:52 pm
- Forum: Naming
- Topic: Coordination compound
- Replies: 6
- Views: 879
Re: Coordination compound
Are ligands always nonmetal atoms?
- Sun May 27, 2018 11:41 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR confusion
- Replies: 8
- Views: 1271
Re: VSEPR confusion
Is the VSEPR model connected to determining sigma and pi bonds? If so, how?
- Sun May 27, 2018 11:37 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond angle
- Replies: 9
- Views: 978
Re: Bond angle
Do you know if these types of molecules (molecules with lone pairs) be tested?
- Sun May 27, 2018 11:20 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Any Other Shapes?
- Replies: 7
- Views: 879
Re: Any Other Shapes?
Will we learn the VSEPR model for molecules with one or more lone pair? So far, we've only learn the basic geometry for molecules with zero lone pairs.
- Sun May 20, 2018 4:15 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: formal charge
- Replies: 11
- Views: 1607
Re: formal charge
"When trying to minimize the formal charge, how do you know which element you should minimize first?"
According to my observation, it seems as if altering the bond arrangements affects the formal charge of multiple elements simultaneously. I don't think there is a specific order.
According to my observation, it seems as if altering the bond arrangements affects the formal charge of multiple elements simultaneously. I don't think there is a specific order.
- Sun May 20, 2018 4:10 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3006540
Re: Post All Chemistry Jokes Here
My chem puns rarely get a reaction.
- Sun May 20, 2018 3:32 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3006540
Re: Post All Chemistry Jokes Here
A Hug without u
Hg
is just mercury
Hg
is just mercury
- Sat May 12, 2018 9:28 pm
- Forum: Resonance Structures
- Topic: Resonance Structures and Formal charges
- Replies: 7
- Views: 944
Re: Resonance Structures and Formal charges
The formal charge is used to discover the most stable Lewis structure. That structure will have the least number of formal charges not equal to zero. Resonance structure represents the various locations of the electron pairs. The electron can go back and forth between atoms.
- Sat May 12, 2018 9:15 pm
- Forum: Resonance Structures
- Topic: Resonance structure of benzene
- Replies: 4
- Views: 619
Re: Resonance structure of benzene
I don't believe we are expected to know this for Chem 14A, but one of the TAs mentioned a simplified version in which benzene is represented by a hexagon with three double bonds. The carbons are implied to be located at each point with the correct amount of hydrogen atoms attached.
- Sat May 12, 2018 9:09 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge of ClO2- [ENDORSED]
- Replies: 4
- Views: 3158
Re: Formal charge of ClO2- [ENDORSED]
ClO2 is drawn O-Cl-O.
- Wed May 02, 2018 12:38 am
- Forum: Quantum Numbers and The H-Atom
- Topic: Principle quantum number and orbital angular momentum quantum number
- Replies: 2
- Views: 390
Re: Principle quantum number and orbital angular momentum quantum number
l can equal values from 0 to n-1. That means l can equal 0, 1, 2, 3, and 4 but NOT 5 or higher for this homework problem. l=2 refers to the electron(s) in a specific subshell.
- Thu Apr 26, 2018 9:27 am
- Forum: Einstein Equation
- Topic: Planck's Constant Value [ENDORSED]
- Replies: 7
- Views: 3331
Re: Planck's Constant Value [ENDORSED]
For homework, I like to use the more accurate value for Planck's constants. For tests, I use 6.626 x 10^(-34) because the tests are timed, and it's faster to input this version.
- Thu Apr 26, 2018 9:18 am
- Forum: Einstein Equation
- Topic: Difference Between Equations [ENDORSED]
- Replies: 4
- Views: 837
Re: Difference Between Equations [ENDORSED]
You can think of the equation, E = hc/λ, as a combination of two equations: E = hv and c = λ v
From the speed of light equation, you can rearrange the variables to solve for frequency: v = c/λ. When you substitute c/λ for v, you get E = hc/λ.
From the speed of light equation, you can rearrange the variables to solve for frequency: v = c/λ. When you substitute c/λ for v, you get E = hc/λ.
- Thu Apr 26, 2018 9:07 am
- Forum: Properties of Light
- Topic: Equations for light [ENDORSED]
- Replies: 4
- Views: 550
Re: Equations for light [ENDORSED]
A few variations from this week's homework problems (depending on which values are given):
E = hv
hc / v
c = λ v
λ = c/v
λ = hc / E
λ = h / p
λ = h / mv
v = c/λ
v = h / E
(v here represents frequency except for the de Broglie equation)
E = hv
hc / v
c = λ v
λ = c/v
λ = hc / E
λ = h / p
λ = h / mv
v = c/λ
v = h / E
(v here represents frequency except for the de Broglie equation)
- Sun Apr 22, 2018 2:08 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3006540
Re: Post All Chemistry Jokes Here
I heard oxygen and magnesium were going out and I was like OMg!
- Sun Apr 22, 2018 2:06 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3006540
Re: Post All Chemistry Jokes Here
You must be a compound of beryllium and barium...because you’re a total BaBe
- Sat Apr 21, 2018 12:29 am
- Forum: Significant Figures
- Topic: Sig Fig Accuracy [ENDORSED]
- Replies: 6
- Views: 902
Sig Fig Accuracy [ENDORSED]
When performing dimensional analysis, why are sig figs applied to each 'step' and not just the final answer? Won’t this result in a less accurate final answer?
- Sun Apr 15, 2018 11:59 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: dilution
- Replies: 4
- Views: 638
Re: dilution
In dilutions, the value of n, the moles of solute, ALWAYS remains the same. That is why N(initial) = N(final). And thus, M(i)V(i) = M(f)V(f). V(f) also, is the value of the initial solution PLUS the additional solution required for diluting.
- Sun Apr 15, 2018 11:54 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Accuracy vs Precision
- Replies: 23
- Views: 2597
Re: Accuracy vs Precision
When visualizing accuracy, think of a bulls-eye target with many shots near the center, but scattered within the radius of the bulls-eye in any direction. The results appear very disbursed. When visualizing precision, think of a bulls-eye target with many shots clumped together, but not necessarily ...
- Sun Apr 15, 2018 11:50 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Mass percentage
- Replies: 8
- Views: 992
Re: Mass percentage
100 grams is merely a value that facilitates the conversion from mass percentage composition to actual mass composition. Rather than multiplying the percentage by 100 (and essentially only moving decimal points), you multiply by the specific given grams of the sample.
- Sun Apr 15, 2018 11:46 pm
- Forum: Empirical & Molecular Formulas
- Topic: Oxygen "missing" in mass percentage composition questions
- Replies: 1
- Views: 185
Oxygen "missing" in mass percentage composition questions
The mass of oxygen is sometimes not given. You should check to see if this the case by comparing the percentage mass to total mass. Don't forget to subtract the mass composition of the given elements from the total to determine the mass of oxygen. The mass of oxygen is sometimes not given due to the...
- Sun Apr 15, 2018 11:42 pm
- Forum: Balancing Chemical Reactions
- Topic: Fastest way to balance chemical equation
- Replies: 9
- Views: 16455
Re: Fastest way to balance chemical equation
A fast way to know whether to increase the stoichiometric coefficient of an equation is recognizing that an odd number of elements such as oxygen on one side does not match the even number of say O2 (oxygen as a diatomic molecule).
- Sun Apr 15, 2018 11:41 pm
- Forum: Balancing Chemical Reactions
- Topic: Fastest way to balance chemical equation
- Replies: 9
- Views: 16455
Re: Fastest way to balance chemical equation
A fast way to know whether to increase the stoichiometric coefficient of an equation is recognizing that an odd number of elements such as oxygen on one side does not match the even number of say O2 (oxygen as a diatomic molecule).
- Sun Apr 15, 2018 11:29 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Review Question [ENDORSED]
- Replies: 3
- Views: 543
Re: Review Question [ENDORSED]
The molarity formula is moles of solute (n) divided by liters of solution (V). The units of molarity is mol/L (M). M can be substituted with c, which indicates a broader calculation of concentration.