Search found 46 matches

by Yuchien Ma 2L
Sat Mar 18, 2017 2:06 pm
Forum: *Alkenes
Topic: Are alkenes and alkynes considered functional groups?
Replies: 4
Views: 633

Re: Are alkenes and alkynes considered functional groups?

On the 2015 exam, Q10A did not list them as functional groups.
Since it says that any functional group that is incorrect will have points taken off, I was wondering if we needed to circle to double bonds as well since they are alkenes.
by Yuchien Ma 2L
Sat Mar 18, 2017 1:52 pm
Forum: *Alkenes
Topic: Are alkenes and alkynes considered functional groups?
Replies: 4
Views: 633

Are alkenes and alkynes considered functional groups?

Are alkenes and alkynes considered functional groups?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:47 am
Forum: *Alkanes
Topic: Why is methyl placed after isopropyl?
Replies: 3
Views: 302

Re: Why is methyl placed after isopropyl?

So we don't ignore the prefix "iso"?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:45 am
Forum: *Alkanes
Topic: 1.24
Replies: 1
Views: 202

1.24

For #1.23 on the organic textbook, ( I can't write the question here because it is just diagrams)
Aren't the 2nd and 3rd molecule the same?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:43 am
Forum: *Alkanes
Topic: Diene, triene usage [ENDORSED]
Replies: 1
Views: 399

Diene, triene usage [ENDORSED]

When do we use diene and triene in our names?
For example, for some problems the answer key would say 2-hexene, but other times it would say ...hept-1,4-diene.
Do we use only diene and triene for cyclic molecules or something else?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:37 am
Forum: *Alkanes
Topic: Neobutane vs. tetra-butane
Replies: 1
Views: 269

Neobutane vs. tetra-butane

On #17 on the organic workbook, the answer key says "tetra-butane". But what is the difference between that and neobutane?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:36 am
Forum: *Alkanes
Topic: Why is methyl placed after isopropyl?
Replies: 3
Views: 302

Why is methyl placed after isopropyl?

Why is methyl placed after isopropyl?
by Yuchien Ma 2L
Sat Mar 04, 2017 11:35 am
Forum: *Alkanes
Topic: Memorizing the First Ten Alkenes
Replies: 3
Views: 1848

Re: Memorizing the First Ten Alkenes

To remember the first four just use this:
Monkeys Eat Peanut Butter
It's a funny little sentence that helps you memorize it.
The rest of them are the same as normal prefixes
by Yuchien Ma 2L
Mon Feb 20, 2017 4:18 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetic
Replies: 3
Views: 353

Re: Kinetic

You ALWAYS use the slowest rate.
by Yuchien Ma 2L
Sat Feb 11, 2017 10:35 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Is E a path function or state function?
Replies: 2
Views: 467

Is E a path function or state function?

Is E a path function or state function?
by Yuchien Ma 2L
Fri Feb 10, 2017 10:29 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram
Replies: 1
Views: 195

Re: Cell Diagram

You want the HIGHEST E cell, so it will always be the larger number minus the smaller number.
So whichever has a smaller E cell potential will always be reversed.
by Yuchien Ma 2L
Sat Feb 04, 2017 9:29 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: How to keep track of significant figures?
Replies: 2
Views: 387

Re: How to keep track of significant figures?

Use the least precise number in the question. You use the least precise number to decide how many sig figs to use.
by Yuchien Ma 2L
Sat Feb 04, 2017 9:20 pm
Forum: Balancing Redox Reactions
Topic: Oxidation/Reduction Method
Replies: 1
Views: 210

Re: Oxidation/Reduction Method

I'm not sure what your first question means, but I'll go ahead and answer your second question. For electrochemistry, it is agreed that the oxidation state of O is -2, and H is usually +1 (although in some cases it can be -1), and we only know the charge of an element IF it is an ion, otherwise we w...
by Yuchien Ma 2L
Sun Jan 29, 2017 1:30 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: "Favorable" chemical reaction
Replies: 3
Views: 515

Re: "Favorable" chemical reaction

When delta G is negative, the reaction is favorable (spontaneous).
When delta G is positive, the reaction is unfavorable (non-spontaneous).
When delta G is equal to zero, the system is at equilibrium.
by Yuchien Ma 2L
Tue Jan 24, 2017 5:14 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 8.67
Replies: 1
Views: 228

8.67

Calculate the reaction enthalpy: a) 3C262 (g) --> C6H6 (g) I drew the Lewis structure and added all the bond enthalpies, and then used the equation: E bonds broken - E bonds formed I found the reaction enthalpy to be -3409 kJ/ mol, while the solutions manual says -460 kJ/mol. I don't know really how...
by Yuchien Ma 2L
Tue Jan 24, 2017 5:03 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Number 57 in Chapter 8 Homework
Replies: 2
Views: 287

Re: Number 57 in Chapter 8 Homework

You can opt to use the equation: E bonds broken - E bonds formed to solve this problem. The enthalpy of formation of C2H2 is -1300 kJ/mol, and H2= 286 kJ/mol, and C2H6 = -1560 kJ/mol. Using this equation, you end up with: Enthalpy of Formation of C2H6= (-1300 + 2(-286))- (-1560)= -312 kJ/mol I find ...
by Yuchien Ma 2L
Tue Jan 24, 2017 4:55 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Homework Problem 8.51
Replies: 2
Views: 308

Re: Homework Problem 8.51

I have the same problem. Since density is g*cm^-3, I end up with an extra "g" unit that I cannot cancel out.
I don't really understand the solutions manual's way of explaining it.
by Yuchien Ma 2L
Sun Jan 15, 2017 1:34 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Ch 8 #31 (8.31)
Replies: 3
Views: 570

Ch 8 #31 (8.31)

Calculate the heat released by 5.025 g of K (g) at 0.400 atm as it cools from 97.6o C to 25.0o at (a) a constant pressure and (b) constant volume. Assume that krypton behaves as an ideal gas.

Can anyone explain how to solve this?
Thanks.
by Yuchien Ma 2L
Sun Jan 15, 2017 12:47 pm
Forum: Calculating Work of Expansion
Topic: Comparing the amount of work done
Replies: 1
Views: 241

Comparing the amount of work done

How do we compare the amount of work done? Do we just disregard the negative signs when comparing the amount of work done, or do we have to take in account the direction in which the work is done?
For instance, is -343 J of work considered more work than +120 J of work?
by Yuchien Ma 2L
Sat Jan 14, 2017 1:36 pm
Forum: Phase Changes & Related Calculations
Topic: Most Helpful Resource
Replies: 14
Views: 1314

Re: Most Helpful Resource

I personally found the chemistry community to be the most helpful out of all the resources available, because it is available 24/7 and you can post whenever and wherever. Whenever you have a question, you can always post it online, and then multiple people will answer your question through different...
by Yuchien Ma 2L
Thu Dec 01, 2016 11:08 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids
Replies: 1
Views: 307

Strength of Acids

Why is HClO 2 more acidic than HBrO 2 ? Isn't the H-Cl shorter and isn't Cl more electronegative than Br, so wouldn't HBrO 2 lose the H + proton more easily? The solutions manual says something about electronegativity making the H-O bond stronger, but is anyone able to explain that more clearly? Tha...
by Yuchien Ma 2L
Thu Nov 24, 2016 3:06 pm
Forum: Student Social/Study Group
Topic: Help with Coordination Compounds?
Replies: 6
Views: 910

Re: Help with Coordination Compounds?

How do you exactly find out if the complex has an overall negative or positive charge? You can usually tell by the name. A negative coordination compound will have the suffix "-ate" in the name; positive ones will not. You can also add up all the charges of the central transition metal an...
by Yuchien Ma 2L
Thu Nov 24, 2016 3:02 pm
Forum: Student Social/Study Group
Topic: Final Study Group
Replies: 12
Views: 1385

Re: Final Study Group

I'm interested as well!
by Yuchien Ma 2L
Fri Nov 11, 2016 11:04 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: H2O Ligand
Replies: 1
Views: 376

H2O Ligand

I have a question about H2O.
It has two valence electron lone pairs (4 valence electrons total), so why can't it make two polar coordinate bonds and be a bidentate ligand?
Why is it always a monodentate ligand?
by Yuchien Ma 2L
Fri Nov 11, 2016 10:48 am
Forum: Naming
Topic: 17.31 [ENDORSED]
Replies: 1
Views: 235

17.31 [ENDORSED]

For 17.31, part d, why is the aqua is written with the O backwards, like OH2, instead of H2O?
Also, how do we determine the order in which we put the ions when given the name of the coordinate compound?
by Yuchien Ma 2L
Mon Nov 07, 2016 10:31 pm
Forum: Naming
Topic: So lost on the naming
Replies: 4
Views: 484

So lost on the naming

I am completely confused about naming the coordinate compounds.
Do we need to know the latin names for all of the transition metals?
What is the order in which we put the different ligands before the ion?

Thanks in advance for your help.
by Yuchien Ma 2L
Sat Nov 05, 2016 6:03 pm
Forum: Trends in The Periodic Table
Topic: Px py and pz
Replies: 4
Views: 908

Re: Px py and pz

We generally only use this when determining hybridizations.
by Yuchien Ma 2L
Sat Nov 05, 2016 6:02 pm
Forum: DeBroglie Equation
Topic: Neutrons
Replies: 4
Views: 610

Re: Neutrons

Neutrons do have wave-like properties.
by Yuchien Ma 2L
Sun Oct 30, 2016 12:49 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent and Ionic Character
Replies: 3
Views: 538

Re: Covalent and Ionic Character

The higher the difference in electronegativity, the more ionic character a molecule has. That's because the higher the difference in electronegativity, the more unevenly the electrons would be shared between them.
Hope this helps!
by Yuchien Ma 2L
Wed Oct 26, 2016 10:24 pm
Forum: Electronegativity
Topic: Trends in periodic table
Replies: 6
Views: 682

Re: Trends in periodic table

Yes, the trends do not apply to the noble gases, and sometimes they go against the trends. For instance, the electron affinity of noble gases would be negative since they don't need that extra e-.
Hope this helps!
by Yuchien Ma 2L
Wed Oct 19, 2016 8:19 pm
Forum: Hybridization
Topic: Building Up Principle [ENDORSED]
Replies: 1
Views: 330

Re: Building Up Principle [ENDORSED]

Electrons naturally repel each other, so they will fill up the empty orbitals before they fill up the already filled ones. Think of it like pairs of bus seats...you will sit in an empty pair of seats if you can. You will only sit with a stranger if there are no empty pairs of seats left, and you abs...
by Yuchien Ma 2L
Sat Oct 15, 2016 3:57 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.29
Replies: 1
Views: 212

2.29

How many electrons can have the following quantum number:
a) n=2, l=1
b) n=4, l=2, ml=-1
c) n=2, l=1, ml= 0
d) n=7

I don't really even know how to start...please help!
by Yuchien Ma 2L
Sat Oct 15, 2016 3:09 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.21
Replies: 5
Views: 390

Re: 2.21

Thank you so much for your help!
I have a much better understanding of the quantum numbers now.
by Yuchien Ma 2L
Sat Oct 15, 2016 3:00 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.21
Replies: 5
Views: 390

Re: 2.21

Thanks, that really helped.
But what if n=6, and l is equal to 0,...n-1? What would l = 5 mean?
by Yuchien Ma 2L
Sat Oct 15, 2016 2:44 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 2.21
Replies: 5
Views: 390

2.21

#2.21: What are the principal and orbital angular momentum quantum numbers for each of the following orbitals: a) 6p b) 3d c) 2p d) 5f i understand how to get the n (principal quantum number), it's the same as the energy level in front of the orbital. But I'm very confused about how to get the orbit...
by Yuchien Ma 2L
Fri Oct 14, 2016 10:16 pm
Forum: Electronegativity
Topic: Periodic Trends
Replies: 3
Views: 469

Re: Periodic Trends

Most periodic trends such as electronegativity and ionization energies goes up and right, only atomic radius is the exact opposite; it goes left and down. That's how I remember it.
Hope this helps!
by Yuchien Ma 2L
Fri Oct 14, 2016 10:11 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Vs Covalent bonds
Replies: 4
Views: 576

Re: Ionic Vs Covalent bonds

Ionic bonds are much stronger than covalent bonds just because of the fact that the high difference between their electronegativity. An ionic compound is formed between nonmetals and metals, and a covalent compound is formed between two or more nonmetals. An easy way to remember is that you know met...
by Yuchien Ma 2L
Fri Oct 14, 2016 10:05 pm
Forum: Lewis Structures
Topic: Lewis Structure Octet Rule [ENDORSED]
Replies: 3
Views: 558

Re: Lewis Structure Octet Rule [ENDORSED]

Electrons will always fill empty shells first (Hund's rule) so make sure that you draw out the electrons on all four sides before you start pairing them. For instance, carbon will have four valence electrons, one on each side, never two together on one side because electrons naturally repel each oth...
by Yuchien Ma 2L
Tue Oct 04, 2016 9:21 pm
Forum: Properties of Light
Topic: HW Question Ch #27 [ENDORSED]
Replies: 5
Views: 917

Re: HW Question Ch #27 [ENDORSED]

Thanks for the explanation!
It's so much clearer than the one in the solutions manual :D
by Yuchien Ma 2L
Mon Oct 03, 2016 10:56 pm
Forum: Properties of Light
Topic: HW Question Ch #27 [ENDORSED]
Replies: 5
Views: 917

HW Question Ch #27 [ENDORSED]

A lamp rated at 32 W (1 W = 1 J * s^-1) emits violet light of wavelength 420 nm. How many photons of violet light can the lamp generate in 2.0s? How many moles of photons are emitted in that time interval? I got the first part, 32 J * s^-1 * 2.0 s = 64 J But I'm confused about the second part. I am...
by Yuchien Ma 2L
Mon Oct 03, 2016 10:48 pm
Forum: Properties of Light
Topic: Question about n1 and n2
Replies: 4
Views: 1272

Re: Question about n1 and n2

Thanks a lot for the clarification!!
The second link really helped.
by Yuchien Ma 2L
Sun Oct 02, 2016 5:44 pm
Forum: Properties of Light
Topic: Question about n1 and n2
Replies: 4
Views: 1272

Question about n1 and n2

What is n1 and n2 in the Rydberg Equation?
Is n1 the initial energy level and n2 the final energy level?
If I do that then sometimes I'd end up with a negative frequency.

Thanks in advance
by Yuchien Ma 2L
Sun Oct 02, 2016 4:15 pm
Forum: Significant Figures
Topic: Rounding sig figs [ENDORSED]
Replies: 1
Views: 345

Rounding sig figs [ENDORSED]

If my answer is 1.987*10^-3, and I need 2 sig figs, should I write my answer as 2*10^-3 or 2.0*10^-3?
by Yuchien Ma 2L
Tue Sep 27, 2016 8:56 pm
Forum: Molarity, Solutions, Dilutions
Topic: G #17 b
Replies: 4
Views: 961

G #17 b

Determine the mass of CuSO 4 • 5H 2 O that must be used to prepare 250 mL of 0.20 M CuSO 4 (aq). The solutions manual says 12 g which is what I got if I set up the equation as followed and solve for x: x grams * 1 mol/249.611 * 1 L/0.2 mol = 0.250 L But isn't CuSO 4 • 5H 2 O a hydrate? Therefore the...
by Yuchien Ma 2L
Tue Sep 27, 2016 4:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G5
Replies: 6
Views: 1069

Re: Fundamentals G5

I finally got it!
Thanks for your help
by Yuchien Ma 2L
Mon Sep 26, 2016 11:01 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals G5
Replies: 6
Views: 1069

Re: Fundamentals G5

Using the formula M1V1=M2V2 I set up the following:

(0.159338 mols Na+/L) (V1) = (2.15*10^-3 mols Na+/L) (0.250 L)

and solving for V1 I got:
V1= 3.373 * 10^-3 liters, 3.373 mL, which is different from the solutions manual (which is 13.5 mL).

Please help!

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