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Chemistry help

Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
Right, I'm trying to teach myself Higher Chemistry in 2 weeks, cause I have done very little work up til now and my exam is 2 weeks today.

Anyway, a question about equilibrium.

At the point of equilibrium, the rates of the forward and the reverse reactions are the same. Say in water, the H2O molecules are becoming H+ and OH- ions at the same rate as the OH- and H+ ions are becoming H2O, so the concentrations of H2O and OH-/H+ ions are always proportionally the same.

Since equilibrium reactions are reversible, the activation energy of the forward and the reverse reaction will be equally affected with the addition of a catalyst, so both will increase rate by the same amount. Remember however that adding a catalyst does not alter the position of the equilibrium.

The next bit I don't understand. When you increase the concentration of the reactant(s), the equilibrium moves to the right. The word rate confuses me. Surely when you increase the concentration of the reactants, the rate of the forward reaction would increase. Wouldn't the rate of the reverse reaction then have to increase proportionally for the rates to stay the same, and so the reaction to obtain equilibrium? I don't understand how the position of equilibrium can move, and yet the rates of the reactions still stay the same.

Or have I got things completely wrong, and it's not the rates that are the same, instead they are just proportionally equal?

If any of you read to the end of this, well done!

Comments

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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    ...if you want maths help, come to me.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Originally posted by Sanj33v
    ...if you want maths help, come to me.

    I can do maths :p Maths is my best subject at the moment.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Ooo, Ooo, got it sorted! It's all in the concentrations!!
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Good for you! :D

    If you need help with law, economics, business... fire away.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    good luck and if you need help, im useless, so dont come to me!:D
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    If you need any more help with chem contact Stinger (b/f) he's into that kinda of thing, studying a Bio medical Science degree!!

    kitty xx
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    I wouldn't be any help with chemistry I'm afraid. I can't even get the equilibrium of molecules right, or whatever, when making a cup of tea. :(

    Mr_Wobble ;)
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    After reading that I'm so glad I'm not taking higher Chemistry next year.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Originally posted by Liquid:MM
    After reading that I'm so glad I'm not taking higher Chemistry next year.

    I'm feeling bloody stupid for taking it. I mean I struggled a little with standard grade, dunno wtf possessed me to take Higher.
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Glad your sorted! Got A level chemistry on the 24th June. :nervous: :nervous:
    Last exam though, so means i can really enjoy myself at the thought that its over!!
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    Former MemberFormer Member Posts: 1,876,323 The Mix Honorary Guru
    Argh!! i have my As level chem practical on wednesday!!! :nervous: :nervous: im sposed to be doing the planning exercise now....but im kinda distracted + i dunno what to write...
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