Search found 29 matches

by Hope_Pham_1G
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: 242

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?
by Hope_Pham_1G
Sun Jun 10, 2018 3:35 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Methyl-2-Cyanoacrylate
Replies: 1
Views: 85

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.
by Hope_Pham_1G
Sun Jun 10, 2018 3:16 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Heme complex structure_coordination number
Replies: 1
Views: 62

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?
by Hope_Pham_1G
Sat Jun 02, 2018 2:02 pm
Forum: Hybridization
Topic: How to identify pi and sigma bonds
Replies: 4
Views: 130

Re: How to identify pi and sigma bonds

Why can there be two pi bonds but not two sigma bonds.
by Hope_Pham_1G
Sat Jun 02, 2018 1:58 pm
Forum: Hybridization
Topic: σ bonds
Replies: 9
Views: 239

Re: σ bonds

How come double bonds and triple bonds have pi bonds?
by Hope_Pham_1G
Sat Jun 02, 2018 1:52 pm
Forum: Naming
Topic: Coordination compound
Replies: 6
Views: 271

Re: Coordination compound

Are ligands always nonmetal atoms?
by Hope_Pham_1G
Sun May 27, 2018 11:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR confusion
Replies: 8
Views: 243

Re: VSEPR confusion

Is the VSEPR model connected to determining sigma and pi bonds? If so, how?
by Hope_Pham_1G
Sun May 27, 2018 11:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond angle
Replies: 9
Views: 205

Re: Bond angle

Do you know if these types of molecules (molecules with lone pairs) be tested?
by Hope_Pham_1G
Sun May 27, 2018 11:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Any Other Shapes?
Replies: 7
Views: 293

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.
by Hope_Pham_1G
Sun May 20, 2018 4:15 pm
Forum: Formal Charge and Oxidation Numbers
Topic: formal charge
Replies: 11
Views: 411

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.
by Hope_Pham_1G
Sun May 20, 2018 4:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 886506

Re: Post All Chemistry Jokes Here

My chem puns rarely get a reaction.
by Hope_Pham_1G
Sun May 20, 2018 3:32 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 886506

Re: Post All Chemistry Jokes Here

A Hug without u
Hg
is just mercury
by Hope_Pham_1G
Sat May 12, 2018 9:28 pm
Forum: Resonance Structures
Topic: Resonance Structures and Formal charges
Replies: 7
Views: 264

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.
by Hope_Pham_1G
Sat May 12, 2018 9:15 pm
Forum: Resonance Structures
Topic: Resonance structure of benzene
Replies: 4
Views: 163

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.
by Hope_Pham_1G
Sat May 12, 2018 9:09 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge of ClO2- [ENDORSED]
Replies: 4
Views: 273

Re: Formal charge of ClO2- [ENDORSED]

ClO2 is drawn O-Cl-O.
by Hope_Pham_1G
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: 104

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.
by Hope_Pham_1G
Thu Apr 26, 2018 9:27 am
Forum: Einstein Equation
Topic: Planck's Constant Value [ENDORSED]
Replies: 7
Views: 2754

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.
by Hope_Pham_1G
Thu Apr 26, 2018 9:18 am
Forum: Einstein Equation
Topic: Difference Between Equations [ENDORSED]
Replies: 4
Views: 224

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.
by Hope_Pham_1G
Thu Apr 26, 2018 9:07 am
Forum: Properties of Light
Topic: Equations for light [ENDORSED]
Replies: 4
Views: 131

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)
by Hope_Pham_1G
Sun Apr 22, 2018 2:08 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 886506

Re: Post All Chemistry Jokes Here

I heard oxygen and magnesium were going out and I was like OMg!
by Hope_Pham_1G
Sun Apr 22, 2018 2:06 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 886506

Re: Post All Chemistry Jokes Here

You must be a compound of beryllium and barium...because you’re a total BaBe
by Hope_Pham_1G
Sat Apr 21, 2018 12:29 am
Forum: Significant Figures
Topic: Sig Fig Accuracy [ENDORSED]
Replies: 6
Views: 333

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?
by Hope_Pham_1G
Sun Apr 15, 2018 11:59 pm
Forum: Molarity, Solutions, Dilutions
Topic: dilution
Replies: 4
Views: 228

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.
by Hope_Pham_1G
Sun Apr 15, 2018 11:54 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Accuracy vs Precision
Replies: 23
Views: 700

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 ...
by Hope_Pham_1G
Sun Apr 15, 2018 11:50 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mass percentage
Replies: 8
Views: 348

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.
by Hope_Pham_1G
Sun Apr 15, 2018 11:46 pm
Forum: Empirical & Molecular Formulas
Topic: Oxygen "missing" in mass percentage composition questions
Replies: 1
Views: 116

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...
by Hope_Pham_1G
Sun Apr 15, 2018 11:42 pm
Forum: Balancing Chemical Reactions
Topic: Fastest way to balance chemical equation
Replies: 9
Views: 651

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).
by Hope_Pham_1G
Sun Apr 15, 2018 11:41 pm
Forum: Balancing Chemical Reactions
Topic: Fastest way to balance chemical equation
Replies: 9
Views: 651

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).
by Hope_Pham_1G
Sun Apr 15, 2018 11:29 pm
Forum: Molarity, Solutions, Dilutions
Topic: Review Question [ENDORSED]
Replies: 3
Views: 211

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.

Go to advanced search