Chemistry Help Anyone? - TennisForum.com
Old Dec 15th, 2006, 04:01 AM Thread Starter
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Chemistry Help Anyone?

I know this is so basic, but I forget:

Which contains the same number of ions as the value of Avogadro's constant?
A) 0.5 mol NaCl
B) 0.5 mol MgCl2
C) 1.0 mol Na2O
D) 1.0 mol MgO

Apparently the answer is A, but I dunno why!
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Old Dec 15th, 2006, 04:13 AM Thread Starter
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Re: Chemistry Help Anyone?

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Old Dec 15th, 2006, 04:16 AM
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Re: Chemistry Help Anyone?

1 mol NaCl ---> `1 mol Na+ ions and 1 mol Cl- ions = 2 mol of ions = 2* Avogadro # of ions

0.5 mol NaCl = total of 1 mol of ions = Avogadro # of ions

0.5 mol of MgCl2 --> 1.5 *Avogadro # of ions
1 mol Na2O --> 3*Avogadro # of ions
1 mol MgO --> 2*Avogadro # of ions
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Old Dec 15th, 2006, 04:20 AM Thread Starter
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by Just_Me View Post
1 mol NaCl ---> `1 mol Na+ ions and 1 mol Cl- ions = 2 mol of ions = 2* Avogadro # of ions

0.5 mol NaCl = total of 1 mol of ions = Avogadro # of ions
So, you take the 2 x Avogradro's #
and then multiply by 0.5?

Also another question:

CO2 +3H2 --> CH3OH + H2O

What is the maximum amount of methanol that can be formed from 2 mol of carbon dioxide and 3 mol of hydrogen?

A) 1 mol
B) 2 mol
C) 3 mol
D) 5 mol
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Old Dec 15th, 2006, 04:23 AM
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Re: Chemistry Help Anyone?

1 mol of CH3OH
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Old Dec 15th, 2006, 04:24 AM Thread Starter
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by Just_Me View Post
1 mol of CH3OH

And how'd you get that?
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Old Dec 15th, 2006, 04:26 AM
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by nbaker53 View Post
And how'd you get that?
from the eqn

1 mol of carbon dioxide with 3 mol of hydrogen gives 1 mol of methanol

2 mol of co2 would require 6 mol of h2 to give 2 mol of methanol

2 mol of co2 with 3 mol of h2 would give 1 mol of methanol and the extra mol of co2 will remain unreacted
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Old Dec 15th, 2006, 04:28 AM Thread Starter
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by Just_Me View Post
from the eqn

1 mol of carbon dioxide with 3 mol of hydrogen gives 1 mol of methanol

2 mol of co2 would require 6 mol of h2 to give 2 mol of methanol

2 mol of co2 with 3 mol of h2 would give 1 mol of methanol and the extra mol of co2 will remain unreacted
I don't understand how you got those values
What ratio are you using?
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Old Dec 15th, 2006, 04:31 AM
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by nbaker53 View Post
I don't understand how you got those values
What ratio are you using?
from the chemical eqn i got the values

multiply by 2 throughout to get the second set of numbers
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Old Dec 15th, 2006, 04:33 AM Thread Starter
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by Just_Me View Post
from the chemical eqn i got the values

multiply by 2 throughout to get the second set of numbers

I still don't understand?
Is there anyway you could make things more simpler?
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Old Dec 15th, 2006, 04:37 AM
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Re: Chemistry Help Anyone?

CO2 +3H2 --> CH3OH + H2O

1 mol CO2 + 3 mol H2 ---> 1 mol CH3OH + 1 mol H2O

2 mol CO2 + 6 mol H2 ---> 2 mol CH3OH + 2 mol H2O
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Old Dec 15th, 2006, 04:38 AM
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Re: Chemistry Help Anyone?

CO2 +3H2 --> CH3OH + H2O

you got that... you see that you need 1 mol CO2 and 3 mol H2 to get one mol Ch3OH, right? so if you you have 2 mol CO2 it would look like this :

2CO2 + 6H2 --> 2CH3OH + 2H2O

but you do not have 6 mol H2, you only have three which means it doesnt matter if you have 1 mol or two 2 CO2; as long as you only have 3 mol H2 you can only get 1 mol CH3OH out of it

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Old Dec 15th, 2006, 04:40 AM Thread Starter
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Re: Chemistry Help Anyone?

Quote:
Originally Posted by rrfnpump View Post
CO2 +3H2 --> CH3OH + H2O

you got that... you see that you need 1 mol CO2 and 3 mol H2 to get one mol Ch3OH, right? so if you you have 2 mol CO2 it would look like this :

2CO2 + 6H2 --> 2CH3OH + 2H2O

but you do not have 6 mol H2, you only have three which means it doesnt matter if you have 1 mol or two 2 CO2; as long as you only have 3 mol H2 you can only get 1 mol CH3OH out of it
Okay, I think I sort of get it! Thanks
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Old Dec 15th, 2006, 04:40 AM
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Re: Chemistry Help Anyone?

i thought this thread was about how to find a chemtry between a guy and girl - Just make eye contact with other!

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Old Dec 15th, 2006, 04:46 AM Thread Starter
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Re: Chemistry Help Anyone?

Okay, another question. Not related to moles and stuff like that:

What statement is a correct description of electron loss in this reaction?

2Al + 3S --> Al2S3

A) Each aluminium atom loses two electrons
B) Each aluminium atom loses three electrons
C) Each sulfure atom loses two electrons.
D) Each sulfure atom loses three electrons.

I know this is so basic, I just can't remember any of this!
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