Anyone know how to do this chemistry stuff?

madog

madog

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My teacher went to fast and I didnt get all the note stuff. It's Stoichiometry. Anyway heres the problem:

2 Na + 2 H2O --> 2 NaOH + H2
Calculate the number of excess reagent units remaining when 1.78x10^23 H2O molecules and 1.57x10^23 Na atoms react?

Molar Masses (g)
Na- 23.000
H2O-18.015
NaOH- 40.007
H2- 2.016

And if you can tell me, I also need to know how to do % yield. I don't no where the hell you get the actual value from and all that stuff.

I hope to God there is some Chemists out there because Halflife2.net is my only hope!
 
AH nvm this was an easy one i got it. But can you still tell me how to do % yield someone.
 
Ah come on dude! I'm so frustrated with this! If just one person could tell me I'd be their slave for a day.
 
Percent yield = amount of stuff you got / amount of stuff you supposed to get * 100
 
This is what sophomre chemistry was like for me:

Came in, put on headphones.
"Martin!"
"what Mr. Boyington?"
"turn down the volume"
"Okay"
(doesn't do shit)
(Takes tests)
(receives a million As while the rest of the class gets Cs)
(wins)
 
joule said:
www.homeworkhelp.com
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I dont have time to sign up for that shit! I've got 4 hours before this is due! Easily can be done in that time but not if you don't know how to do it.
And I already know how to calculate % yield. Getting the values that set you up for it is whats giving me trouble.
 
Just wait untill you do university level chemistry. Make sure you learn this stuff well if you plan on taking senior level highschool chemistry.
 
Stoichiometry is fun, AND it's a cool word.

Anyways...
For percent yield I'm guessing they give you the mass (or moles) of the product that was actually produced. Then you use stoichiometry (using the values for the limiting reagent if the problem involves limiting reagents..) to find how much mass of that product you would theoretically produce. Then... divide like Nat Turner said.
 
The DemonWithin said:
Just wait untill you do university level chemistry. Make sure you learn this stuff well if you plan on taking senior level highschool chemistry.
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Ya I know this easy Im just not exactly thinking straight at the moment. Screw college chemistry that is like my worst nightmare, I'm not taking it again after this. But anyway I just learned the due date on my assignment was changed so scratch this thread!:laugh:
 
Problem is my professor spends so much time making jokes he doesnt teach the chemistry very well. He gives some weird explanation like explaining this chapter like baking cookies. I just want to know how to do the damn stuff, but o well.
 
madog said:
Problem is my professor spends so much time making jokes he doesnt teach the chemistry very well. He gives some weird explanation like explaining this chapter like baking cookies. I just want to know how to do the damn stuff, but o well.
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Stop whining and just read the damn textbook. Nothing is that challenging.
 
Nat Turner said:
Stop whining and just read the damn textbook. Nothing is that challenging.
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wtf I wasn't whining I was just commenting on my proffesor's teaching. Also, if you read my previous post you would know that I said I don't need help anymore so calm the hell down.
 
madog said:
Ya I know this easy Im just not exactly thinking straight at the moment. Screw college chemistry that is like my worst nightmare, I'm not taking it again after this. But anyway I just learned the due date on my assignment was changed so scratch this thread!:laugh:
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Ah, I didnt say it was easy, just easier heheh. I thought it was hard when I was doing it.
 
madog said:
wtf I wasn't whining I was just commenting on my proffesor's teaching. Also, if you read my previous post you would know that I said I don't need help anymore so calm the hell down.
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madog said:
I just want to know how to do the damn stuff, but o well.
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Sounds like whining to me. So I suggested reading the textbook.
 
Nat Turner said:
Sounds like whining to me. So I suggested reading the textbook.
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stop babysitting this thread countering his every point and trying to criticize him, there are better ways to find thrills trust me :p
 
babyheadcrab said:
stop babysitting this thread countering his every point and trying to criticize him, there are better ways to find thrills trust me :p
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OMG don't diss my styles and thrill-seeking attitude. I'd like to trust you, but first I would like to see your qualifications. Post them in a neat bulleted form please, ok? kkthx
 
I only just saw this thread or i'd have helped you with this, i love chemistry and biology more-so. But i hope you sorted it all out. atomic mass divided by weight of the compound you have usually solves most questions :) Alkaline metals aren't too hard.
 
madog said:
My teacher went to fast and I didnt get all the note stuff. It's Stoichiometry. Anyway heres the problem:

2 Na + 2 H2O --> 2 NaOH + H2
Calculate the number of excess reagent units remaining when 1.78x10^23 H2O molecules and 1.57x10^23 Na atoms react?
Click to expand...

Whats that? Moles or mol dm-3?
 
Well said, I had Chemistry 10th grade, I hated it, I always had a B no matter what, despite A's on tests and quizzes. She was nice too, the teacher I mean. It's funny, AP Calculus this year is easier than Honors Chemistry will ever be, ok maybe it isn't that funny.
 
find the limiting reagent
convert to moles and subtract the relative number of moles from the limiting reagent with the other reagent's relative number of moles.
What you have left is the left over reagent
 
I got a good nights sleep and the next day I totally owned this assignment, I guess my head was just more in the forum than in my homework, but thanks for your help guys.
So there is no more need to bitch at me Nat. Although you will probably find something else to yell about.
 
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