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define equilibrium constant and rate constant

I know how to work them out but I can't talk about them fluently:
my explanation of rate constant: a value that increases with rate:frown:...a book I have describes it as something like- the link between the rate of reaction and the concentration of the reactants to the power of their orders...:s-smilie:
Original post by Yasinhooo
I know how to work them out but I can't talk about them fluently:
my explanation of rate constant: a value that increases with rate:frown:...a book I have describes it as something like- the link between the rate of reaction and the concentration of the reactants to the power of their orders...:s-smilie:


http://lmgtfy.com/?q=rate+constant

The rate constant tells you how the rate depends on concentrations of reagents. You know that rate is usually dependent on concentration, right? Well the rate constant is just the constant of proportionality.

Let's take a simple first order reaction:

ABA \rightarrow B

The rate is proportional to the conc of A

rate[A]\mathrm{rate}\propto [A]

or

rate=k[A]\mathrm{rate}=k[A]

The equilibrium constant is the constant that tells you how the concentrations of the products and reactants depend on each other in an equilibrium situation. e.g.

A+BC+DA + B \leftrightharpoons C + D

the equilibrium constant, Kc is

Kc=[C][D][A][b]K_c=\dfrac{[C][D]}{[A][b]}
(edited 12 years ago)
Reply 2
Original post by Plato's Trousers
http://lmgtfy.com/?q=rate+constant

The rate constant tells you how the rate depends on concentrations of reagents. You know that rate is usually dependent on concentration, right? Well the rate constant is just the constant of proportionality.

Let's take a simple first order reaction:

ABA \rightarrow B

The rate is proportional to the conc of A

rate[A]\mathrm{rate}\propto [A]

or

rate=k[A]\mathrm{rate}=k[A]



The equilibrium constant is the constant that tells you how the concentrations of the products and reactants depend on each other in an equilibrium situation. e.g.

A+BC+DA + B \leftrightharpoons C + D

the equilibrium constant, Kc is

Kc=[C][D][A][b]K_c=\dfrac{[C][D]}{[A][b]}

just wanted a definition from a former or current A2 student...seeing the single book I looked in explained it in 4 diff ways.

The ones I'll remember:
Rate constant is an indicator of the rate of the reaction- the larger it's value- the faster the rate of reaction.

equilibrium constant- a numerical value that indicates where the equilibrium lies within the equation. Where the reactions in favour of the reactants or products.

Are these fine?
Original post by Yasinhooo
just wanted a definition from a former or current A2 student...seeing the single book I looked in explained it in 4 diff ways.

The ones I'll remember:
Rate constant is an indicator of the rate of the reaction- the larger it's value- the faster the rate of reaction.

equilibrium constant- a numerical value that indicates where the equilibrium lies within the equation. Where the reactions in favour of the reactants or products.

Are these fine?


yes. Those are ok for basic working definitions.
Reply 4
Original post by Plato's Trousers
yes. Those are ok for basic working definitions.


will they ever ask us to define them? If so how manymarks would these get?
Reply 5
This is how I would define them.

The rate constant is the constant of proportionality between the rate of a reaction and the product of the concentrations of the rate-determining reactants. The higher the rate constant, the faster the reaction occurs.

The equilibrium constant is a measure of the extent to which a reaction will proceed towards completion at a certain temperature. Increasing the temperature will change the equilibrium constant depending on the dH for the reaction. An equilibrium constant >1 means the reaction will head towards completion. An equilibrium constant <1 means the reaction will tend towards not occuring. It is calculated by...

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