January 15, 2025, 11:21:16 AM
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Topic: double check please? Rearranging equilibrium equation into quadratic form  (Read 4364 times)

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Offline rcole23

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Answer is not the same as the book, but sometimes this book is wrong... Anyway here is my best shot

25.0 = 2x2 / [2.00 - x] [3.00 - x]

2x2 = 25.0 * [2.00 - x] [3.00 - x]

FOIL

2x2 = 25.0 (6.00 - 2.00x - 3.00x + x2)

2x2 = 150 - 50x - 75x + 25x2

0 = 150 - 50x - 75x + 25x2 - 2x2

0 = 150 - 125x + 23x2

I don't know how far off I am, if someone can give me a hand...  I think I am way off in left field.

Offline Stephen

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Answer is not the same as the book, but sometimes this book is wrong... Anyway here is my best shot

25.0 = 2x2 / [2.00 - x] [3.00 - x]

2x2 = 25.0 * [2.00 - x] [3.00 - x]

FOIL

2x2 = 25.0 (6.00 - 2.00x - 3.00x + x2)

2x2 = 150 - 50x - 75x + 25x2

0 = 150 - 50x - 75x + 25x2 - 2x2

0 = 150 - 125x + 23x2

I don't know how far off I am, if someone can give me a hand...  I think I am way off in left field.


this is simple maths
solve it using formula:

if ax2+bx+c=0 is given then:
x1,2=(-a+-sqrt(b2-4ac))/2

Offline rcole23

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Answer is not the same as the book, but sometimes this book is wrong... Anyway here is my best shot

25.0 = 2x2 / [2.00 - x] [3.00 - x]

2x2 = 25.0 * [2.00 - x] [3.00 - x]

FOIL

2x2 = 25.0 (6.00 - 2.00x - 3.00x + x2)

2x2 = 150 - 50x - 75x + 25x2

0 = 150 - 50x - 75x + 25x2 - 2x2

0 = 150 - 125x + 23x2

I don't know how far off I am, if someone can give me a hand...  I think I am way off in left field.


this is simple maths
solve it using formula:

if ax2+bx+c=0 is given then:
x1,2=(-a+-sqrt(b2-4ac))/2

I am a self taught correspondence student asking for help, telling me it is simple does not get me anywhere, and the book I am studying from is sometiems wrong.

Did I do the rearranging correctly into the ax2+bx+c=0 format or not?  and that formula that u gave me is yes the next step but only if I have the correct numbers in my formula..

Really now a bit more help than that poor reply please.  I am trying to learn here.

What I am doing is rearranging an equilibrium equation into the quadratic formula and then continuing on with the quadratic equation to solve the problem giving amount of moles of substance at equilibrium.  This is just one step in the process.

Offline Borek

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0 = 150 - 125x + 23x2

Looks OK to me.
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