CHEMISTRY COMMUNITY

Josh_Zhong_1F

Q: Why does hamburger yield lower energy than steak?
A: Because it's in the ground state.

Josh_Zhong_1F

Q: What do you do with a dead chemist?
A: Barium

Josh_Zhong_1F

OHHHH..I think I understand what you mean Professor. Please correct me if I am wrong, O3 reacts with BrO3-; therefore, O3 is an oxidizing agent because O3 oxidation number is 0 while Br oxidation number is +5 Br- reacts with O2; therefore, Br- is a reducing agent because Br- oxidation number is -1 w...

Josh_Zhong_1F

Hi,
But for this problem, the solution says that O3 is the oxidizing agent and Br- is the reducing agent.
I thought both O3 and Br- are oxidizing agent..

When both O3 and O2 have oxidation number "0", how do we determine whether it is oxidizing or reducing?

Thanks,

Josh_Zhong_1F

GOT MOLE PROBLEMS?
CALL AVOGADRO AT 602-1023

LOLOLOLOLLLLLLLLLL,

Josh_Zhong_1F

GOT IT....

THANKS!!

Josh_Zhong_1F

AH..
Got it..

Thanks!!

Josh_Zhong_1F

Hello,
I am wondering why the book use standard enthalpy of vaporization of 43.5kJ per mol instead of 40.7kJ per mol or 44.0 kJ per mol in homework problem 9.15(b)

Josh_Zhong_1F

You need to download something called "silver light" , and sometimes is difficult to play.
Internet browser is better or apple's safari browser is fine too.

Josh_Zhong_1F

How about the chemical workers — are they unionized?

Josh_Zhong_1F

Hi,
The book example on 9.6, I do not quite understand the cooling of acetone vapor from boiling to desired temperature, why does the equation use heat capacity Cp,m=4R ?

Thanks!

Josh_Zhong_1F

Hi,

Thank you Professor.
I have contacted the technician, and bruincast is working great now!

Thanks,

Josh_Zhong_1F

Hi,
On page 293, Example problem 8.9, step 2 states that there is 4H2O2 in the reaction.
I cannot seem to figure out where is the 4H2O2 come from.
Would it be an error?

Thanks,

Josh_Zhong_1F

Yea, it happens in all three different lectures for every recorded sessions.

Josh_Zhong_1F

Hi Professor,
The Bruincast video and audio seem to have lacking of output. Many of the full sentences that were spoked were not recorded.
Just want to bring to your attention.

Thanks,

Josh_Zhong_1F

What Is The Chemical Formula For Coffee?

A. CoFe2

LOLOLOLLLL..

Josh_Zhong_1F

I understand the fact that spending $100 is no different for a billionaire. But how does the 5% rule work in the context of solving x? How do we determine when to use the 5% rule? When do we use it????

Thanks,

Josh_Zhong_1F

Hi,
What is the difference between Amphoteric and Amphiprotic?
Also, what is the relationship between Amphiprotic and Autoprotolysis?

Thanks,
Josh

Josh_Zhong_1F

A proton, a neutron, and helium walk into a bar and order three beers. The bartender appears with 3 beers and asks the proton, “Are you sure you’re over 21?” The proton replies, “I’m positive.” So the bartender gives him the first beer. He gives the second beer to the neutron and says, “For you, no ...

Josh_Zhong_1F

First of all why do Chemistry graduates typically work in the Pharmaceutical industry, while Pharmacy graduates typically work in a Chemist shop? Anyway, the missus and I are both science graduates, Chemistry for her, and Physics and Computer Science for me. So typical conversations might be… I told...

Josh_Zhong_1F

Hi,

How do you know the compound has a negative has a charge of -3?

Josh_Zhong_1F

Hi,

K3[CoF6], on the course reader, it is named: potassium-hexa-fluoro-cobaltate(III)

Why is it not: potassium-hexa-fluoro-cobalt(III)?
It does not have a negative charge in the complex...Don't we only add ate to complexes that have negative charge?

Thanks,

Josh_Zhong_1F

Hi Emerald, I think the solution is written in a way just to show us the complete molecular orbitals when drawing the diagram for Li. I think it would be better to know the complete molecular orbital diagram and draw it out every time. Because you draw the diagram differently for Z<8 and Z>or = 8

Josh_Zhong_1F

Hi, I have noticed that from the book(page 7 in chapter 1), atomic spectra calculation done by Rydberg could be written using the formula: v(frequency)=R[1/n1^2-1/n2^2]. However, in the course reader, we have done the example on page 48 using a different formula: Change of E=E(final)-E(initial) E(n)...

Josh_Zhong_1F

YOU ARE AMAZING!

Josh_Zhong_1F

Thanks a lot!!

Josh_Zhong_1F

6.40 g of a compound was burned in air and produced 8.80 g of CO2 and 7.20 g of H20. Find the empirical formula of the compound.

I do not know how to approach this kind of problems.
Thanks!

Josh_Zhong_1F

Aluminum and hydrogen chloride, HCI, react to form aluminum chloride in solution, AlCl3, and hydrogen gas. Balanced equation: 2Al + 6HCl -------> 2AlCl3 + 3H2 Question: If you had 5.43 g of aluminum and 7.80 g of hydrogen chloride, how many grams of AlCl3 would you get? I could not figure out where ...

Josh_Zhong_1F

Hi,

Where does the number -2.178x10^-18J come from??

Josh_Zhong_1F

Hi Michelle,
How do you know that nitrogen and oxygen are N2 and O2, which is in gas state?

Josh_Zhong_1F

THANK YOU!

Josh_Zhong_1F

Hard Water is water that has high mineral content, mainly calcium ions(Ca2+) and magnesium ions(Mg2+). A concentration above 5.30x10^-3 is considered to be very hard water. Assuming that there are no magnesium ions present, is a 0.400 L solution of 0.120 g CaCO3 and 0.155 g CaSO4 very hard water? To...

Josh_Zhong_1F

The work function for lithium is 4.6x10^-19 J 1) Calculate the lowest frequency of light that will cause photoelectric emission. 2) What is the maximum energy of the electrons emitted when light of 7.3x10^14 Hz is used? 1) When it asks for lowest frequency, I look at it as it means longest wavelengt...

Josh_Zhong_1F

Question:
When nitrogen and oxygen react in the cylinder of an automobile engine, nitric oxide, NO, is formed. Write a balanced equation for this reaction.

Comment:
I do not know how to write this formula out and then balance it. Nitrogen and oxygen both have negative charge. Please advise..

CHEMISTRY COMMUNITY

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Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: 14.5 Half Reactions

Re: 14.5 Half Reactions

Re: Post All Chemistry Jokes Here

Re: Homework Problem 9.15(b)

Re: Book example problem 9.6

Homework Problem 9.15(b)

Re: Bruincast Audio Problem

Re: Post All Chemistry Jokes Here

Book example problem 9.6

Re: Bruincast Audio Problem

Error in the text book?

Re: Bruincast Audio Problem

Bruincast Audio Problem

Re: Post All Chemistry Jokes Here

Re: 5 Percent Rule

Difference between Amphoteric and Amphiprotic

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: Negative charge. Add Ate to the end

Naming Ligands

Re: Chapter 4 Problem 51

Clarification on ENERGY LEVEL concept

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Quiz 1 Fall 2015 #5 [ENDORSED]

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Re: Naming Chemical Formula and Balancing Chemical Equations [ENDORSED]

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Naming Chemical Formula and Balancing Chemical Equations [ENDORSED]