## Zero order

$\frac{d[R]}{dt}=-k; [R]=-kt + [R]_{0}; t_{\frac{1}{2}}=\frac{[R]_{0}}{2k}$

Marsenne Cabral 1A
Posts: 59
Joined: Fri Sep 28, 2018 12:19 am

### Zero order

What would an example of a chemical reaction equation of a zero order reaction?

Karina Jiayu Xu 4E
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Joined: Fri Sep 28, 2018 12:29 am

### Re: Zero order

i am also confused about this... what do the different orders actually mean?

ryanhon2H
Posts: 60
Joined: Fri Sep 28, 2018 12:28 am

### Re: Zero order

A zero order reaction is one where the rate is independent of the concentration. An example could be the decomposition of nitrous oxide on a hot platinum wire. The rate of that reaction doesn't depend on the concentration of nitrous oxide, it depends on whether surface area runs out on the wire for decomposition to occur.

chloewinnett1L
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Joined: Fri Sep 28, 2018 12:20 am

### Re: Zero order

Another example could be the evaporation of water. The rate at which liquid water becomes water vapor does not depend on a "concentration," but rather on a multitude of other things (amount of water/temperature/pressure/etc)

Carlos De La Torre 2L
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Joined: Tue Oct 09, 2018 12:16 am

### Re: Zero order

A zero-order reaction is one in which the rate is independent of the concentration, we use artificial zero-order reactions to determine the order of reactants in a reaction. By supplying an excess amount of all reactants except one and then varying the concentration of the non-excess reactant to find its order.

Nina Do 4L
Posts: 61
Joined: Fri Sep 28, 2018 12:27 am

### Re: Zero order

A zero order reaction does not change if the concentration of the reactants change. It is only based on the k. Therefore, the equation would be rate=k.

However, first order reactions do depend on the concentration of reactants and it's equation will be rate =k[A]. When the concentration of reactant A changes, the rate changes as well.

Third order reactions are dependent on the reactants squared. So it's reaction equation would be rate=k[A]^2 and when [A] changes, squared, rate will change and be squared too.

Ethan Breaux 2F
Posts: 63
Joined: Sat Sep 29, 2018 12:16 am

### Re: Zero order

so if I'm understanding this correctly... zero orders are just equal to the constant (k). how would we write them in the k[A][B]^2 thing or would be leave them out?

Mukil_Pari_2I
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Joined: Fri Sep 28, 2018 12:29 am

### Re: Zero order

Ethan Breaux 2F wrote:so if I'm understanding this correctly... zero orders are just equal to the constant (k). how would we write them in the k[A][B]^2 thing or would be leave them out?

Well, for a zero order reaction, since the rate law is fully independent of the concentration of the reactant, the rate law equation would just be the rate constant (k). There would be no concentration of the reactant in the equation.

Lynsea_Southwick_2K
Posts: 55
Joined: Fri Sep 28, 2018 12:25 am

### Re: Zero order

Zero-order: a rxn for which the rate is independent of concentration of the reactant (Rate= k x (concentration)0 = k)

BenJohnson1H
Posts: 68
Joined: Fri Sep 28, 2018 12:17 am

### Re: Zero order

Correct, for a 0 order reaction, the reactant's concentration that is zero order would be left out

Irene Zhou 1E
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Joined: Fri Sep 28, 2018 12:18 am

### Re: Zero order

The order of the reaction just shows if the rate of the reaction is dependent on the concentrations. Thus, if one reactant is zero order, that means the concentration of that reactant does not affect the rate of reaction.