Calling all chemists

Jason Danger Keyes

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Mar 4, 2009
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the equilibrium constant for the reaction: MgCl2(s) + 1/2O2(g ) MgO(s) + Cl2(g )
is 3.85x10^-3 at a certain temperature. What is the equilibrium constant for the reaction below at the same temperature?
Cl2(g ) + MgO(s) MgCl2(s) + 1/2O2(g )


does this mean anything to anyone? :s
 

Lord Beautiful

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Aug 13, 2008
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Sorry, it's been a while since I had chemistry. Still, I feel like I should know how to solve that.
 

Xpwn3ntial

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Dec 22, 2008
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If you posted this two years ago, I could have told you. Sorry.

Wait, wouldn't it be the same?
 

spartan231490

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Jan 14, 2010
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don't feel like doing the math, but wouldn't it be like 2.7-9ish x10^3 or something like that. been a long time sinse i did chem, neat question though.
It's the multiplicative inverse right?
 

Jason Danger Keyes

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Mar 4, 2009
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Also, this:

a 0.010 M solution of a weak monoprotic acid is 3% dissociated. what is the equilibrium constant, Ka, for this acid?


My friend is losing her mind trying to fight through Uni chem, and I just want to help her out however i can. Also, if anyone is or knows a good chem tutor we're open for negotiation
 

wasalp

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Dec 22, 2008
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well I dont think you have enough information to find that figure. Unless you didnt post it all.

edit(3): nvm here is a link its in french but just look at part b) on page 14. You have to do table to find x.forgot the link sorry: http://theory.chem.uottawa.ca/chm1711/course/equilibrium.pdf

edit(2): cant help you with the acid one havent donne dissociation yet.
 

Jason Danger Keyes

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Mar 4, 2009
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a weak monoprotic acid is 2.0% dissociated in a 0.20 M solution. what is the acid-ionization constant, Ka, for this acid?
 

wasalp

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also try this website, its saved my ass for another one of my classes.

http://www.khanacademy.org/#Chemistry

they have a bunch of tutorials on many different subjects.

edit: the guy made this website to create a free education movement, its awesome.
 

Heart of Darkness

The final days of His Trolliness
Jul 1, 2009
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For the acid-ionization constant, there's a formula for that:

K[sub]a[/sub] = ([A[sup]-[/sup]][H[sup]+[/sup]]) / [HA]

where [A[sup]-[/sup]] is the concentration of the anion, [H[sup]+[/sup]] is the concentration of the proton, and [HA] is the concentration of the acid (all at equilibrium). Figuring out how much of the acid has dissociated should be easy to figure out:

3% of 0.010 is 0.00030, so the acid ionization constant equation for the first problem should be

K[sub]a[/sub] = [0.00030 M][sup]2[/sup]/(0.0097 M) = 9.3 x 10[sup]-6[/sup] M.[footnote]Wikipedia, Acid Dissociation Constant [http://en.wikipedia.org/wiki/Acid_dissociation_constant][/footnote]

[hr]

For the chemical equilibrium, there's also an equation for that (again, thanks, Wikipedia!):

For an chemical reaction aA + bB + ... --> ... yY + zZ, where the lower case letters are coefficients and the upper case letters are the reactants and products, the equilibrium constant K[sub]c[/sub] can be expressed as

K[sub]c[/sub] = (...[Y][sup]y[/sup][Z][sup]z[/sup]) / ([A][sup]a[/sup][sup]b[/sup]...)

Beyond that, though, no idea how to help on that problem. Sorry. It's been two years since I did chemistry in any way, shape, or form. Hope it helps, though.[footnote]Wikipedia, Equlibrium Constant [http://en.wikipedia.org/wiki/Equilibrium_constant][/footnote]

EDIT: Although, I'm thinking it will be the inverse. If the equilibrium constant of the first expression is K[sub]1[/sub], then the equilibrium constant of the second, K[sub]2[/sub], should be

K[sub]2[/sub] = (K[sub]1[/sub])[sup]-1[/sup]

by virtue of the products and reactants having switched places in the expression.

EDIT2: Added my sources.
 

Jason Danger Keyes

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Mar 4, 2009
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wasalp said:
also try this website, its saved my ass for another one of my classes.

http://www.khanacademy.org/#Chemistry

they have a bunch of tutorials on many different subjects.

edit: the guy made this website to create a free education movement, its awesome.
Heart of Darkness said:
You, sirs, are gentlemen and scholars
 

Jason Danger Keyes

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Mar 4, 2009
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One more dissociation question, we really do appreciate this so much, thank you.

Al of the following reactions are affected by an increase in pressure except:
NH4HS(s) NH3(g ) + H2S(g )
C(s) + H2O(g ) CO( g) + H2(g )
3Fe(s) + 4H2O(g ) Fe3O4(s) + 4H2(g )
NH3(g ) + HCl(g ) NH4Cl(s)
H2(g )+ I2 2HI (g )
 

Anarchemitis

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Dec 23, 2007
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ShredHexus said:
the equilibrium constant for the reaction: MgCl2(s) + 1/2O2(g ) MgO(s) + Cl2(g )
is 3.85x10^-3 at a certain temperature. What is the equilibrium constant for the reaction below at the same temperature?
Cl2(g ) + MgO(s) MgCl2(s) + 1/2O2(g )


does this mean anything to anyone? :s
Means stuff to me, but it's been over a year since I did that stuff. Sorry mate.