liquids in reaction rate equation?

[osprey099]

If I have the equation: X(aq) + H2O (l) <-> Y(aq) + Z(aq), is the rate equation Rate = k[X] or is it Rate = k[X][H2O]? I think it's Rate = k[X] but in TBR Kinetics Passage 7, Questions 46 and 47, they put [H2O] into the equation..

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[circulus vitios]

Is that the real reaction, or just your own genericized version? Water does appear in the equation if it's a reactant. It does not appear if it's a solvent.

 

[Sandstorm]

Is that the real reaction, or just your own genericized version? Water does appear in the equation if it's a reactant. It does not appear if it's a solvent.

Incorrect. Pure solids and liquids do not appear.

 

[Sandstorm]

If you have pure water, the concentration will be 1M no matter if you have a microliter or a kiloliter.

 

[slz1900]

Incorrect. Pure solids and liquids do not appear.

Not true. You ignore liquids IF their concentration is not changing. We don't know whether or not that is the case here. It would depend on whether or not there was a lot of water on the reactant side starting out. And even if you do leave it out, the reaction would still be a second order, pseudo first order reaction.

 

[circulus vitios]

Incorrect. Pure solids and liquids do not appear.

Uh I did a few questions yesterday from the TPR-H SW that had water in the rate equation.

 

[Mehd School]

Concentrations of liquids and solids do not change in these instances, and therefore should not be included in the reaction rate.